CSMLS mock exam questions/past questions Flashcards
Which of the following actions should be taken when the hematoxylin and eosin stain lack 3 distinct shades of pink?
Check the pH of eosin
A dark brown pigment is noted on formalin-fixed, hematoxylin, and eosin-stained sections. What action can prevent this from occurring?
Maintain formalin at a neutral pH
Which of the following situations will cause mast cells to turn blue during metachromatic staining?
Decreased pH of toluidine blue
Which of the following staining problems results from the omission of 1% periodic acid solution in the Jones Methenamine silver technique?
Failure to stain the basement membrane
Which of the following specimen orders prioritizes the processing of microbiology specimens correctly?
CSF, blood culture, urine, swab in a transport medium
Which of the following actions should be taken when tissue sections stained with hematoxylin and eosin show pale cytoplasmic staining?
Check the pH of eosin and adjust with acetic acid if necessary
Explanation: Eosin is an acidic dye, and its pH affects the staining quality. If tissue sections show pale cytoplasmic staining, it indicates potential issues with eosin staining. Checking the pH of eosin and adjusting it with acetic acid if necessary can help restore optimal staining conditions, leading to improved cytoplasmic staining in histological specimens.
Which of the following reagents is used as the mordant and oxidant in the Weigert’s hematoxylin?
Ferric chloride
Explanation: In the Weigert’s hematoxylin staining method, ferric chloride serves as the mordant and oxidant. It helps intensify the staining of nuclei with hematoxylin and promotes the formation of a complex that binds to cellular structures.
Which of the following factors is a possible cause for cocci in chains to appear pink on a gram stain?
The patient is on antibiotics
Explanation: Antibiotic use can affect the cell wall of bacteria, leading to altered staining characteristics. In the case of cocci in chains appearing pink on a Gram stain, it suggests that the bacteria may have lost their ability to retain the crystal violet dye due to antibiotic-induced changes in cell wall structure.
Which naturally occurring antibody(ies) is(are) found in the serum of a group A Rh negative patient
a. Anti-B
b. Anti-D
c. Anti-A,B
d. Anti-D and Anti-B
A
Holes are noted in a cryostat section of muscle. Which of the following is the most likely cause?
a. Too small clearance angle
b. Improper adjustment of the antiroll plate
c. Freezing the section in frozen isopentane in liquid nitrogen
d. Snap freezing the muscle in liquid nitrogen
D
Explanation: Snap-freezing is a process where a tissue is brought down to a temperature below -70C using liquid nitrogen to preserve the tissue morphology and to prevent formation of ice crystals. However, liquid nitrogen will bubble violently when in direct contact with the tissue. Hence, tissue is first submerged into a container isopentane, which then the entire container is lowered into liquid nitrogen. Since isopentane will not form bubbles like liquid nitrogen, this prevents the tissue from getting holes.
Which of the following is true regarding H&E staining using an automated stainer?
a. the staining should be microscopically checked daily using known control tissues
b. the staining should be checked daily only if you are preparing your own staining reagents
c. the staining should always be checked microscopically slide-by-slide
d. microscopic stain checks are not if you are purchasing your reagents
C
Explanation: (A) and (D) are invalid since staining should be checked whether commercial or in-house reagents are used. (B) is too time consuming and impractical. (C) is the proper way to check the quality of the staining. Control tissues will show whether the expected staining features have been stained properly (colour, intensity, and specificity).
Which of the following is true of quality control materials for internal QC?
a. they should be run daily for a week to collect values required to create Levey-Jennings plots
b. they must always have a known value directly traceable to a reference method
c. they should approximate the chemical and physical properties of the sample being tested
d. they should sit on the bench and continue to be used until the bottle is empty or values are > +2SD
C
Explanation: QC materials simulate the composition of patient samples in order to minimize the matrix effect and to correctly reflect the expected performance with patient samples. Matrix effect is the effect on an analytical method caused by all other components of the sample except the except the compound of interest. As opposed to standard reagents, QC reagents do not need a known value, as long as their measured values fall within the acceptable range on the levy-jennings graph. Most QC materials degrade quickly at room temperature; hence they are stored in refrigerators with a few exceptions. The mean and standard deviations of Levy Jennings plots are calculated from QC values collected over a MONTH not a week.
During a routine quality control check, a Kirby-Bauer disc susceptibility test is performed and the resulting zones of inhibition are too large. Which of the following is a possible cause of this result?
a. antibiotics stored at higher temperature than recommended
b. antibiotic discs applied immediately after inoculation of plate
c. inoculum too dense
d.agar depth too thick
B
Explanation: What effect does each answer have on the zone size? An overly dense inoculum means more bugs are added to the plate, which will overcome the effect of the drug causing a falsely small zone size. High temperature can destroy the integrity of the antibiotics making it less effective, hence, a falsely small zone size. Thick agar will prevent the antibiotics from diffusing to bugs that are farther from the disc, causing a falsely small zone size. If the disc is applied too soon before the bugs are settled in the agar, the disc can destroy the bugs immediately, causing a falsely large zone size.
Which antibody could be produced by an R1r individual transfused with R2R2 blood?
a. Anti-C
b. Anti-E
c. Anti-c
d. Anti-e
B
Explanation: Patient is CDe/cde (E-antigen negative RBC). Donor is cDE/cDE (E-antigen positive RBC). Hence the donor red cells can induce the patient to form anti-E.
A good screening test for alcohol ingestion employs comparing the calculated osmolality with what other measurement?
a. freezing point depression osmometer measurement
b. boiling point elevation osmometer measurement
c. vapor-pressure osmometer measurement
d. the osmolar gap
A
Explanation:Freezing point depression = Measured osmolality – Calculated osmolality = osmolar gap (i.e. measured osmo vs. calculated osmo). The more solutes in blood, the lower the freezing point (i.e. freezing point depresses) just like the effect of salt on ice. The solutes in our body are mainly sodium, urea, and glucose (2*Na + urea + gluc) which give us our calculated osmolality. However, our measured osmolality will include the above as well as exogenous substance such as methanol, ethylene glycol, acetone, and isopropyl alcohol. A high osmolar gap (measured – calculated) indicates that these exogenous substances may be present in our body.
When performing a D typing on a patient, a technologist observes that the Rh control is positive. As a result, which of the following would he perform next?
a. Full Rh phenotype
b. Repeat D testing with high protein antiserum
c. Weak D test
d. Direct Antiglobulin Test
D
Explanation: Rh control only consists of a high protein reagent with no anti-D. A positive Rh control indicates that the red cells may already be attached by antibodies in vivo, because the protein in the Rh control may have brought the pre-sensitized red cells together to form an agglutinin. Hence, a DAT is done to prove whether the red cells are pre-sensitized or not.
When entering blood gas results manually into the LIS what should be done if a critical value warning appears when a pH value of 7.14 is entered?
a. immediately consult with the supervisor
b. Check for decimal placement
c. Follow the critical value protocol
d. look at previous results
C
Explanation: Any question that has an answer which tells you to follow the protocol/SOP, it’s the always the safest answer and most likely the right one. Delta check is not a useful tool on pH values, since they can fluctuate immensely depending on the patient’s condition.
Gram positive cocci in chains which grow as small translucent colonies surrounded by a clear zone of hemolysis were isolated from a throat swab. These colonies were found to be catalase negative and resistant to a 0.04 unit bacitracin disc. Which of the following tests would be most useful in identifying this organism?
a. antibody latex agglutination
b. Taxo A disk
c. tube coagulase test
d. susceptibility to optochin
A
Explanation: Catalase neg indicates that this bug is a Strep not Staph. Clear zone indicates that it is a Beta-hem Strep rather than an Alpha-hem Strep (i.e. not S. pneumo and viridans). Amongst the beta-hem strep, Group A Strep is susceptible to bacitracin (Taxo A); hence, this can be either Group C or G. In order to differentiate the two, latex agglutination is the best choice.
What should be done with patient results that are outside reference intervals but are within the percent differences programmed into the delta check?
a. repeat the assay
b. Release the results immediately after review
c. phone the results to the doctor
d. have the specimen recollected
B
Explanation: If the result did not violate delta check, there is no need to question whether any error (technical error, ID error…etc.) is involved. It is unnecessary to phone the doctor since the question didn’t state that the result is critical.
What statement about the dry reagent strip blood test is true?
a. a non-hemolyzed trace is present when there are 1-2 RBC/high power field
b. test for blood is positive for hemoglobin and myoglobin
c. test for blood is based on its reaction with oxidase
d. salicylates cause a false positive reaction
B
Explanation: Both hemoglobin and myoglobin will react with the H2O2 on the pad, which gives a positive result. The colour of the urine (brown vs red) and microscopic examination (red cells) can be used to differentiate haemoglobin from myoglobin. Oxidizing reagents such as bleach can also cause a false positive reaction for blood test, however, salicylate is reducing reagent. Oxidase is used to test for urine glucose.
Which of the following antibodies would not show any reactivity when tested against a panel of reagent red blood cells which had been treated with ficin?
a. Anti-Fya
b. Anti-K
c. Anti-E
d. Anti-Jkb
A
Explanation: Enzymes (e.g. ficin and papain) destroy anti-M, N, S, and Duffy (Fya and Fyb).
What does staining leukemic cells for myeloperoxidase help to distinguish?
a. CML from CLL
b. CLL from ALL
c. AML from ALL
d. AML from CML
C
Explanation: MPO (myeloperoxidase) is an enzyme found in neutrophil primary granules and monocyte lysosomes that catalyze H2O2. Both cells are found in AML, hence very reactive with H2O2 in the stain. ALL is mainly lymphocytes, which has no MPO.
A suspect Enterobacteriaceae isoalte was inoculated to a TSI and decarboxylase test. The TSI showed K/A with gas. The decarboxylase showed:
base: purple, turbid
lysine: purple, turbid
ornithine: purple, turbid
a. the organism is a non-fermentative bacillus
b. the organism is viable but does not decarboxylate the amino acid
c. the test is invalid and must be repeated
d. the organism is negative for lysine and ornithine
C
Explanation:
TSI: 0.1% gluc, 1.0% lactose and sucrose, rest is peptone (protein)
Glucose will first be used up (entire tube turns yellow). If the bug is a lactose fermenter, lactose and sucrose will be utilized next and the peptone will remain untouched (entire tube remains yellow = A/A). However, if the bug does not ferment lactose, it will directly move from glucose to protein. Since deamination of protein occurs aerobically (i.e. the top), only the top will change from yellow to red (top is red, bottom stays yellow due to glucose metabolism = K/A). If the bug is a non-fermenter, it can still metabolize (not ferment) glucose, but only weak acids are produce. Hence, the tube will not turn yellow and will remain a peachy red colour. The protein is then metabolized, turning the top red (top is red, bottom retains original peachy red colour = K/NC).
Summary:
K/A = ferments glucose and utilizes the protein (NLF)
A/A = ferments glucose, lactose, and sucrose (LF)
K/NC = utilizes protein (NFB)
Decarboxylase Test: small amt of glucose and lots of protein (lysine/ornithine); base tube contains glucose only
NLF and LF will first ferment the glucose, producing strong acids that turn the entire tube yellow. If the bugs don’t use ornithine or lysine, the tube will remain yellow. If the bugs metabolize lysine or ornithine or both, they will move on to the protein once glucose is depleted, giving the tube a purple colour. Since the base only contains glucose, NLF and LF will make the base turn yellow. However, since non-fermenters do not ferment glucose, but still utilizes glucose through other pathways, only weak acids are formed. The weak acids cannot turn the tube yellow; hence, the base tube will have a turbid purple colour.
Summary:
NLF and LF ferment the glucose in the base and produce strong acid yellow
NFB utilizes glucose in base, but produces weak acid turbid/purple
Since the TSI result (K/A) tells us that the bug is an NLF, but the decarboxylase test indicates that the bug is an NFB. The conflicting results are deemed invalid.
Given the following patient test results, what is the creatinine clearance?
serum creatinine 100 μmol/L
urine creatinine 8.64 mmol/L
24 hour urine volume 2000 mL
BSA 1.73m^2
a. 120 mm/min
b. 16 mm/min
c. 16 ml/min/1.73m^2
d.120 ml/min/1.73m^2
A
Explanation: **Be careful with the units:
i) Convert umol to mol for serum creatinine
ii) Convert 24 hours to 1440 min (because answer is in minutes)
Ucr (mg/dL) Vur (mL/24hrs) over Pcr (mg/dL) 1440 minutes/24hrs times 1.73 over A
- Cr = creatinine clearance
- Ucr = urine creatinine clearance
- Vur = urine volume excreted in 24 hours
- Pcr = serum creatinine concentration
- 1.73/A= normalization factor for body surface area
What happens to hemoglobin’s affinity for oxygen when hemoglobin binds 2,3-DPG?
a. It decreases
b. It increases
c. It remains constant
d. It becomes saturated
A
Explanation: According to the oxygen-hemoglobin dissociation curve, as 2,3-DPG increases, the curve shifts to the right indicating that more oxygen is required to bind and saturate the hemoglobins. This is because 2,3-DPG binds to deoxygenated hemoglobin, making it harder for oxygen to bind (i.e. decreased affinity).
Similarly, increased temperature and pH will also decrease hemoglobin’s affinity for oxygen due to the disruption of bonds.
The Philadelphia chromosome is predominately associated with which leukemia?
a. acute lymphoblastic leukaemia
b. acute myeloblastic leukaemia
c. chronic lymphocytic leukaemia
d. chronic myelogenous leukaemia
D
Explanation: Philadelphia chromosome is commonly associated with CML. It is caused by the translocation of chromosomes 9 and 22, forming a fusion gene, bcr-abl.
A technologist is performing a nitrate reduction test. When dimethyl-α-naphthylamine and sulfanilic acid were added, the medium did not change colour. What should the technologist do?
a. record the test result as positive
b. reincubate the tube overnight
c. Add zinc to the tube
d. record the test result as negative
C
Explanation: One feature of Enterobacteriaceae is its ability to reduce nitrate.
Nitrate –> Nitrite –> Nitrogen
The nitrate reduction test tests for the presence of nitrite (reduced form of nitrate). If nitrite is present, the medium will turn pink. However, some bugs reduce nitrate beyond nitrite to form nitrogen. Since nitrogen is present instead of nitrite, the medium will not change colour. Hence, no change in colour can be caused by either no reduction or reduction beyond nitrite. In this case, zinc is added to the medium. If there is no reduction, zinc will react with the nitrate to form a pink product. However, if there is reduction beyond nitrite (i.e. no nitrate present), zinc will not react and the medium remains unchanged.
i) Nitrate reduced to nitrite: pink after addition of dimethyl-α-naphthylamine and sulfanilic acid
ii) Nitrate reduced to nitrogen: no colour change after addition of dimethyl-α-naphthylamine and sulfanilic acid, and no colour change after addition of zinc
iii) No nitrate reduction: no colour change after addition of dimethyl-α-naphthylamine and sulfanilic acid, and pink after addition of zinc
ii) Nitrate reduced to nitrogen (beyond nitrite)
The alcian blue staining reactions of colonic epithelial goblet cells on serial sections from the same tissue block show the following staining results:
Alcian Blue @ pH 1.0 1+ (stain intensity)
Alcian Blue @ pH 2.5 3+
Alcian Blue @ pH 4.5 3+
a. The colonic epithelial goblet cells contain only carboxylated glycoproteins.
b. The colonic epithelial goblet cells contain neutral glycoproteins.
c. The colonic epithelial goblet cells contain only sulphated glycoproteins.
d. The colonic epithelial goblet cells contain both sulphated and carboxylated glycoproteins.
D
Explanation: Alcian Blue is a cationic dye that binds to the negative charges on glycoproteins. Sulphated glycoprotein (-SO3H) has an isoelectric point (pI) of 0.5, which means only at pH above 0.5 will SO3H become deprotonated, giving it a negative charge (SO3-). On the other hand, the pI for carboxylated glycoprotein (-COOH) is 2.4. Hence, COOH will deprotonate at pH above 2.4. Alcian Blue can only bind to the two glycoproteins at pH’s ABOVE their respective pI.
At pH 1.0, Alcian Blue can only stain sulphated glycoprotein, but not carboxylated glycoprotein.
At pH 2.5 and 4.5, Alcian Blue can bind to sulphated AND carboxylated glycoproteins. Since the intensities increased starting from pH 2.5, the stain must be binding to carboxylated glycoproteins in addition to sulphated glycoproteins. If the intensities remain the same, it’s likely that only sulphated glycoprotein is present.
If QC was performed on a batch of Hugh-Leifson O-F (oxidative-fermentative) media, which of the following results would correspond with acceptable QC?
a. (open) (closed)
Escherichia coli yellow yellow
Pseudomonas aeruginosa yellow blue-green
Acinetobacter lwoffi blue-green blue-green
b. (open) (closed)
Escherichia coli yellow yellow
Pseudomonas aeruginosa yellow yellow
Acinetobacter lwoffi yellow blue-green
c. (open) (closed)
Escherichia coli yellow yellow
Pseudomonas aeruginosa blue-green yellow
Acinetobacter lwoffi blue-green blue-green
d. (open) (closed)
Escherichia coli blue-green blue-green
Pseudomonas aeruginosa yellow blue-green
Acinetobacter lwoffi yellow yellow
A
Explanation: O-F tests for the bacteria’s utilization of glucose in the presence and absence of oxygen. E. coli is a fermenter that can ferment glucose under O2 and ANO2 (both tubes yellow). P. aeruginosa is an oxidizer that can only oxidize glucose under O2 (only open tube is yellow). Acinetobacter lwoffi is an asaccharolytic bug, meaning it doesn’t use glucose at all (neither tubes are yellow).
A 26 year old female out-patient presents to her physician with symptoms of uncomplicated cystitis. A culture of her urine grows gram positive cocci. What organism would these cocci likely represent?
a. Staphylococcus epidermidis
b. Staphylococcus saprophyticus
c. Streptococcus agalactiae
d. Staphylococcus aureus
B
Explanation: Staphylococcus saprophticus is found predominantly in sexually active young outpatient females. Other bugs commonly found in outpatients include E. coli, Proteus mirabilis, Klebsiella, Enterococcus, and Group B Strep.
What should a technologist do if she obtains low results for all analytes in a specimen?
a. look for sampling error such as a clot in the probe or specimen
b. Change the wash reagent for the probe
c. check the patient’s diagnosis for over-hydration
d. check and see if the reagents have expired
A
Explanation: Under these situations, the first approach is to consider possible analytical/technical errors rather than patient’s physiological condition. If the reagents have expired, all patient samples will be affected rather than just one specimen. Also, do not attempt to take any corrective action before determining the cause of the problem. Clots in the probe can decrease the amount of sample being aspirated, thus cause the concentration of all analytes to be low.
What may cause wrinkles in sections during flotation?
a. having the water bath too hot
b. floating the ribbon for too short of time
c. floating the ribbon too slowly
B
Explanation: (A) and (C) will cause the ribbon to disintegrate due to the heat. (B) will not affect the ribbon. When ribbon is wrinkly, leaving it in the waterbath for some time will make the wrinkles disappear.
How many units of packed red cells would be required to raise the hemoglobin of an average sized patient from 80 g/L to 110 g/L?
a. 5
b. 1
c. 7
d. 3
D
Explanation: Every unit of red cells can raise the hemoglobin by 10 g/L.
(110-80)/10 = 3
What does the D-dimer lab test detect?
a. fibrinogen monomer
b. fibrinogen
c. degradation products of both fibrinogen and fibrin
d. fibrin degradation products
D
Explanation: Fibrinogen converts to fibrin. Fibrin will eventually degrade to fibrin degradation products, which includes D-dimer, with the help of the fibrinolytic system.
A control slide is stained with H&E using an automated tissue stainer. Upon microscopic assessment following staining in Harris hematoxylin, the nuclei appear blue-purple with an obvious chromatin pattern. What would be the appropriate action at this stage?
a. prepare a new hematoxylin solution
b. accept the results and continue with the procedure for the rest of the slides
c. decrease the pH of the hematoxylin staining solution
d.increase the pH of the hematoxylin staining solution
B
Explanation: Don’t be tricked! This is how nuclei should appear under H&E stains.
A midstream urine is received in the laboratory from a recently discharged inpatient. The requisition indicates the date of collection as yesterday making the specimen 24.5 hours old but the specimen feels warm to the touch. What should the technologist do?
a. process the specimen following the usual protocol
b. discard the specimen, send out a rejected specimen report
c. call the floor to double-check the collection date
d. process the specimen with a warning about the delay in transportation
C
Explanation: If the urine is still warm, it may still be fresh and that the date/time was mislabelled. Do not process or discard the sample without any confirmation.
What would processing tissues through alcohol stations that are contaminated with water initially result in?
a. incomplete infiltration of the tissue with paraffin
b. incomplete clearing of the tissue
c. excessive hardening of the tissue
d. incomplete fixation of the tissue
B
Explanation: Tissue processing: Dehydration (alcohol) –> Clearing (Xylene) –> Impregnation (paraffin wax)
If alcohol is contaminated, all the proceeding steps will be affected (clearing and impregnation), because xylene and wax are not miscible with water. Both (A) and (C) are correct. However, the question asks what the contamination will “initially” result in, which is the clearing stage.
Every piece of equipment in the laboratory has a log which is used to document QC values during start-up. How can this log be used?
a. to assist in trouble-shooting for random and systemic error
b. to ensure that start-up procedures are performed properly
c. to force every technologist to perform tasks in a uniform manner
d. to prevent errors in the start-up procedure
A
Explanation: The Levey-Jennings chart will show whether a shift or trend is present in the control values, which respectively indicate a possible random or systemic error.
Which of the following is recommended for the detection of penicillin resistance in Streptococcus pneumoniae?
a. beta-lactamase testing
b. nafcillin 10 ug
c. penicillin 10 units
d. Oxacillin 1 ug
D
Explanation: Oxacillin is a quick and inexpensive screen that tests for penicillin resistance. If the bug is resistant to oxacillin, it will be resistant to penicillin. If it is susceptible to oxacillin, we can proceed to test for pen resistance with the penicillin E-test strip (much pricier).
Beta-lactamase test is not a good indicator of penicillin resistance for Strep pneumo, because it is resistant to penicillin through the alteration of its penicillin-binding proteins (PBP’s) rather than using beta-lactamase. Beta-lactamase testing is normally used on Haemophilus influenzae for BLNAR (beta-lactamase negative ampicillin resistant)
A cloudy cerebrospinal fluid has an increased leukocyte count and a decreased glucose concentration. What is the most probable type of meningitis in a patient with these CSF results?
a. bacterial
b. viral
c. fungal
d. tubercular
A
Explanation: Bacterial infection will have increased leukocyte (particularly neutrophils) and decreased CSF glucose level. Viral infection will have increased lymphocytes and normal CSF glucose level.
Which of the following contains only ferric iron?
a. sulfhemoglobin
b. myoglobin
c. methemoglobin
d. oxyhemoglobin
C
Explanation: Methemoglobin carries ferric iron (Fe3+) which is the oxidized form of ferrous iron, and thus has a decreased ability to bind to oxygen.
An immunocompromised 58-year-old female chemotherapy patient received two units of packed RBC. The patient died 3 days later, and the report from the autopsy revealed that her death was due to septic shock. The blood bags were cultured and the following results were noted. Growth of gram-negative rods on both the BAP and MAC
Lactose neg
Sucrose pos
Citrate neg
Indole neg
VP neg
H2S neg
Urea pos
motility @ 22°C pos
motility @ 37°C neg
a. Enterobacter clocae
b. E. coli
c. Yersinia enterocolitica
d. Citrobacter freundii
C
Explanation: Biggest hint is the motility test. A distinctive feature of Yersinia enterocolitica is that it is motile at 22C to 30C, but completely loses motility at 37C. Another hint is that the patient has had a blood transfusion. One way to isolate Yersinia enterocolitica is by the cold enrichment method, where the bugs are incubated at either 37C or 4C. The former shows slowed growth, while the latter exhibits enhanced recovery. Hence, Yersinia enterocolitica is fond of the cold temperature and will survive and multiply in packed red cells.
A grossly lipemic specimen needs to be tested for potassium using a direct ISE method. How should the technologist proceed?
a. perform the testing as usual as lipemia will not affect the results
b. do the tests but note on the report that the lipemia will falsely decrease the results
c. airfuge the specimen before analysis
d. insist that the specimen be re-drawn after the patient has fasted
A
Explanation: There are two ISE methods, direct and indirect. Direct ISE measures on a non-diluted plasma sample while indirect ISE measures on a plasma sample that has been diluted with a large amount of diluent. Direct ISE is not affected by lipemia, whereas indirect ISE is due to the dilution, hence the latter will require the specimen to be airfuged before analysis.
How should a potassium value of 15 mmol/L be interpreted?
a. it is probably due to hemolysis
b. it is probably due to lipemia
c. it is physiologically possible but should be phoned after repeating
d. it is implausible and requires investigation
D
Explanation: The reference range for potassium is 3.5 – 5.0 mmol/L. 15 mmol/L is 5 times higher, which is beyond critical. This is physiological implausible if patient is still alive. One possible cause is that patient sample may have been contaminated by IV fluids containing potassium.
What is an appropriate disposal method for ammoniacal silver solutions?
a. boil off the liquid, then dispose the solute into chemical waste
b. allow the solution to dry, then scrape into chemical waste
c. pour the solution into saturated aqueous sodium chloride and then dispose according to regulations
d. reduce all the silver salts with formaldehyde and then dry the solute before discarding in general waste and pouring the liquid down the drain
C
Explanation: Ammoniacal silver can form extremely explosive silver nitride. Hence, it must be neutralized with saturated aqueous sodium chloride before disposal.
What should be done when a laboratory reporting error is corrected?
a. the correct result should be called and identified as a corrected report followed by documentation of the call
b. all records of the original report should be discarded
c. the person who made the error and their reason for committing it should be found out before the result is corrected
d. the new result should be called and the nurse asked to discard all records of the original report
A
Explanation: All documents should be retained for communication and investigation purpose. It’s more critical that the ward is notified of the correct result before any investigation is made.
Which of the following mothers is a candidate for Rh immune globulin?
a. A neg mother with positive antibody screen (anti-S); A pos newborn
b. O pos mother with negative antibody screen; A pos newborn
c. O neg mother with negative antibody screen; A neg newborn
d. O neg mother with positive antibody screen (anti-D); A pos newborn
A
Explanation: Rh immune globulin is a passive D antibody that removes any Rh pos fetal red cells in mom’s blood stream before they stimulate the mother to form anti-D. In order to be eligible for RhIG, mother must be Rh negative (Rh pos moms won’t form anti-D), baby must be Rh pos (Rh neg baby will not stimulate mom to form anti-D), and that mom has not yet formed an anti-D (thus (D) is not eligible)
A standard with a transmission value of 50% and a concentration of 100 g/L is used to estimate an unknown specimen with a transmission value of 75%. What is the concentration of the unknown specimen in g/L?
a. 150
b. 55
c. 42
d. 67
C
Explanation: Transmission must be converted to absorbance first before calculating for the concentration.
A = 2 – logT%
A1 = 2 – log 50
A2 = 2 – log 75
Since absorbance is directly proportional to concentration (Beer’s law: A = E * b * c)
A1/C1 = A2/C2
Which of the following methods is the safest and most appropriate for disinfecting a cryostat where adequate ventilation is not available?
a. glutaraldehyde solution
b. phenolic compound followed by absolute ethanol
c. formaldehyde vapour
d. hypochlorite solution followed by water
B
Explanation: Never clean a cryostat with water, as it will form ice in the instrument. Hence, the cryostat is regularly maintained by turning it off to allow ice to melt and wiping it down with alcohol. Formaldehyde and gluteraldehyde are fixatives rather than cleaning reagents.
A single tube of cerebrospinal fluid is received in the laboratory and the following tests are requested: total protein, albumin, IgG quantitation, microbial culture, Gram stain, leukocyte count and differential cell count. Where should the sample tube be sent first?
a. chemistry for protein analysis and fractionation
b. hematology for leukocyte count and differential cell count
c. microbiology for microbial culture and Gram stain
d. aliquot small sample and send a portion to each department
C
Explanation: Since Micb requires a sterile, uncontaminated specimen, this department should get the specimen first. Furthermore, only a couple drops of CSF is needed for enrichment broth and staining. Cytospin and inoculation is not mandatory if sample is limited.
Hematology gets the specimen next, because an unspun specimen is needed for cytospin in order to obtain a correct cell count.
Chemistry spins the sample and only takes the supernatant. Hence, Chemistry should be the last department to receive the specimen unless requested otherwise by the physician.
A patient is positive for anti-Fya, anti-Jkb and anti-K. How many units of blood will have to be screened to find two compatible units, given the following antigen frequencies?
Fya positive = 60%
Jkb positive = 70%
K positive = 10%
a. 8
b. 18
c. 24
d. 48
B
100 - positive frequency
FyA: 100-60 = 40
Jkb: 100-70 = 30
K: 100-10 = 90
0.40 x 0.30 x 0.90 x 100 = 10.8 %
11/100 = 2/X = 200/11 = 18
Two levels of QC material and the Westgard 1 2S rule as a warning rule to check the other quality control rules are being used by a technologist. On the same run, one of your QC values is +2.1SD while the other QC value is -2.2SD. What action should be taken on the basis of these QC results?
a. these QC values should be regarded as warnings and the analysis continued
b. both QC values should be repeated and the rules reassessed
c. troubleshoot for systemic error
d. troubleshoot for random error
D
Explanation: Whether it’s inter-run or intra-run, this is a R4S, which indicates a random error.
Which of the following would lead to an inpatient total serum calcium result of less than 1 mmol/L?
a. the specimen may be contaminated with EDTA anticoagulant
b. the specimen may be contaminated with heparin anticoagulant
c. the patient pumped their fist while the tourniquet was on
d. the tourniquet was likely left on for too long
A
Explanation: EDTA is a chelating agent that binds to calcium, causing the serum calcium to be falsely decreased.
What is the calculated serum osmolality in mOsm/kg given the following serum results?
Sodium 145 mmol/L
Potassium 4.2 mmol/L
Chloride 104 mmol/L
Bicarbonate 26 mmol/L
Urea 5 mmol/L
Glucose 10.3 mmol/L
a. 294
b. 305
c. 160
d. 15
B
Explanation: 2Na + Urea + Gluc = 2(145) + 5 +10.3 = 305
Which of the following assays has the poorest precision?
Analyte Mean (mmol/L) Standard Deviation
Calcium 2.5 0.3
Potassium 4.0 0.4
Sodium 140 4.0
Chloride 100 2.5
a. potassium
b. sodium
c. chloride
d. calcium
D
Explanation: Coefficient of variation is a better indicator of precision than standard deviation itself. CV takes into account of the standard deviation with respect to the mean, hence, it’s also known as the relative standard deviation. The smaller the CV is, the higher the precision.
CV = SD / mean
Chloride = 2.5%
sodium = 2.9%
potassium = 10%
calcium = 12%
100 values on a healthy population have Gaussian distribution and give the following values: mean 50 IU/L and SD 5 IU/L. Which of the following statement is true about this population?
a. 95% had values between 45 and 55 IU/L
b. 2.5% had values <40 IU/L
c. 97.5% had values > 60 IU/L
d. 5% were not healthy
B
Explanation: Try plugging in the mean and SD values into this distribution curve.
Since it’s the area between -3SD (35) to -2SD (40) is 2.5%, the answer is (D)
*it’s easier to memorize ~100% instead of 99.7%
Blood from a newborn has low thyroxine (T4) and elevated TSH compared to reference ranges for that age. These results are most consistent with
a. a normal response to pregnancy induced changes in maternal thyroid function
b. congential secondary hypothyroidism
c. congenital hypopituitarism
d. congential primary hypothyroidism
D
Explanation: Hypothyroidism means a low free T3 and free T4. Hypopituitarism is low TSH (hence answer is not (a))
Primary hypothyroidism is commonly caused by dysfunctional thyroid or low iodine diet, resulting in decreased production of T4. Since T4 suppresses the production of TSH (neg feedback), a decreased T4 will lead to an increased TSH.
Secondary hypothyroidism is commonly caused by a dysfunctional pituitary gland, which results in decreased production of TSH. Since TSH stimulates the production of T4, decreased TSH will reduce the production of T4.
Pregnancy is normally associated with hyperthyroidism, which can lead to Grave’s disease.
A pediatric renal transplant patient had a suprapubic urine collection performed. In the lab, a technologist plated the specimen following protocol with a 0.1 mL calibrated loop. At 18 hours there are 8 colonies of a coliform growing on the plate. What colony count would be reported?
a. 8 X 10^6 CFU/L
b. 80,000 CFU/L
c. <10 X 10^4 CFU/L
d. 800,000 CFU/L
B
Explanation:
(# of colonies)/(loop size in mL) * (1000 mL/ 1 L) * (dilution factor if applicable) = CFU/L
(8 CFU / 0.1 mL) * (1000 mL / 1 L) = 80,000 CFU/L
Which of the following is/are true about a cryostat:
a. is a potential infection hazard
b. all of the above
c. is usually maintained at -35C
d. The cryostat is a microtome in a refrigerated cabinet used to cut fixed tissue.
A
Explanation: Cryostat is used to cut UNfixed tissues. Frozen sectioning is used for rapid microscopic analysis of STAT specimen, hence there is no time for fixation. Tissue is frozen with isopentane and liquid nitrogen and cut by cryostat, which is maintained at approximately -20C. Since tissue is not fixed, it is a potential infection hazard. Hence, only (c) is correct.
A technologist did the following to a frozen section of liver. the section was taken through to 70% alcohol, treated with saturated Oil red O in 70% alcohol, rinsed with 70% alcohol, then the nuclei were stained with Harris hematoxylin. The technologist then dehydrated, cleared and mounted the sections in Permount. What results should she see under microscopic observation if unsaturated fats were present in the frozen section.
a. red lipids, blue-purple nuclei
b. red lipids and cytoplasm, blue-purple nuclei
c. the mounted sections would be unstained
d. blue-purple nuclei
D
Explanation: Lipid will dissolve in alcohol. Thus, there will be no staining for lipids. However, the nuclei will remain stained.
You have been asked to freeze a muscle for Muscle Histochemistry. You place isopentane into liquid nitrogen until it has begun to freeze you then place the muscle into the isopentane. The result of your actions are which of the following?
a. the tissue is ruined
b. large ice crystal artifacts
c. properly frozen tissue
d. over frozen tissue
C
Explanation: Snap-freezing is a process where a tissue is brought down to a temperature below -70C using liquid nitrogen to preserve the tissue morphology and to prevent formation of ice crystals. However, liquid nitrogen will bubble violently when in direct contact with the tissue. Hence, tissue is first submerged into a container isopentane, which then the entire container is lowered into liquid nitrogen. Since isopentane will not form bubbles like liquid nitrogen, this prevents the tissue from getting damaged. This is the proper way of freezing a tissue.
When testing your patient sample, you find all 3 screen cells positive at IAT phase. When an antibody panel is done, all cells except one are positive. The patient auto control is negative. Which of the following is the most likely explanation for this reaction pattern?
a. antibody to a high frequency antigen
b. antibody to a low frequency antigen
c. cold reacting autoantibody
d. warm reacting autoantibody
A
Explanation: Since DAT is negative, it is not an autoantibody. All three screen cells and most of the panel cells are positive, which implies that this patient has an antibody against an antigen that occurs on almost all the red cells, in other words, a high-frequency antigen.
- which of the following statements about reticulocytes is false?
a. staining can occur for more than 5min
b. a supervital stained is used
c. RBC inclusions can result in falsely elevated counts
d. polychrome methylene blue stain is used
D
Explanation: either brilliant cresyl blue or new methylene blue is used as the stain. Only inclusions can be viewed with a supervital stain.
- when are automated cell counters required to have calibration check performed?
a. at least every 3 months
b. after replacement of any major part
c. after performing monthly maintenance
d. when the control values are >2 SD from the mean
B
- which of the following procedures could be performed on a hemolysed blood sample?
a. hemoglobin
b. hemoglobin and plts
c. RBC count and hematocrit
d. no results are reportable
A
- For which of the following procedures would heparin be a recommended anticoagulant?
a. platelet count
b. coagulation tests
c. smear based red cell morphology
d. osmotic fragility
D
OF: test to determine if red cells break easily due to increased osmotic stress. Usually caused by thalassemia or hereditary spherocytosis (decreased surface area).
- what is the QC term used to describe the reproductibility of a test?
a. accuracy
b. precision
c. SD
d. specificity
B
- which therapeutic agent affects platelet function?
a. aspirin
b. Coumadin
c. heparin
d. streptokinase
A
Prevents platelets from sticking together.
- for the performance of manual platelet counts, what is the recommended type of microscopy?
a. electron
b. dark-field
c. light
d. phase
D
- the ratio of anticoagulant to blood for coagulation procedures should be 1 to
a. 4.5
b. 7.0
c. 9.0
d. 10.0
C
- what is the coagulation factor that has a sex linked recessive inheritance pattern?
a. factor V
b. factor IX
c. factor X
d. von Willebrand’s factor
B
- the thrombin time will be prolonged in the presence of all the following except:
a. elevated fibrinogen degradation products
b. heparin
c. factor I deficiency
d. factor II deficiency
D
Factor 2 is the prothrombin factor.
- what would be the expected screening test results for a patient with a fibrin stabilizing factor deficiency?
a. prothrombin time prolonged
b. activated partial thromboplastin time prolonged
c. prothrombin time and activated partial thromboplastin time prolonged
d. prothrombin time activated, partial thromboplastin time normal
D
Factor XIII deficiency
- all the following are true of the INR except:
a. INR is dependent on reagents and instrument used
b. INR is calculated using the PT ratio taken to the power of the ISI value
c. the WHO recommends reporting the INR on patients on long-term oral anticoagulant therapy
d. the desired INR on a patient on Coumadin is between 2.0 and 2.5, but may be higher depending on the cause of the patient’s hyper coagulable state
A
- a prolonged APTT result is obtained on a patient diagnosed as having acute DIC. The patient has not yet been treated for this syndrome. How can the prolonged APTT be explained?
a. In addition to DIC, the pt is deficient in a factor required for the intrinsic pathway
b. DIC is characterized by synthesis of less stable coagulation factors, which deteriorate rapidly in the circulation
c. continuous activation of the coagulation system uses some factors more rapidly than the liver can synthesize them
d. the patient has been misdiagnosed, since a prolonged APTT indicates the problem is deficient, not excessive, coagulation
C
- all of the following test results are characteristic of DIC except:
a. decreased fibrinogen concentration
b. negative test for degradation products
c. decreased platelet count
d. prolonged prothrombin time test
B
- a 4 year old child is seen in the ER room with petechiae and a plt count of 15 x 10 ^9/L. She has no previous history of bleeding problems. 3 weeks earlier she had chicken pox. The physician advises the parents to keep the child off the playground to avoid injury, and the child will recover within several weeks to a month with no further treatment. What condition does this child most likely have?
a. essential thrombocythemia
b. idiopathic thrombocytopenic purpura
c. thrombotic thrombocytopenic purpura
d. Wiskott-Aldrich syndrome
B
ITP, also called idiopathic thrombocytopenic purpura, is an autoimmune disorder that may only require monitoring. In contrast, TTP is related to an enzyme that controls how blood clots and leads to life-threatening complications if not treated right away
- An APTT and PT are requested on a patient scheduled for emergency surgery. On an optical density clot detection system, normal and abnormal controls for both tests are within range, but the patients results are extremely prolonged. The patient’s results have been performed in duplicate, but there is sufficient plasma, which is dark amber, to repeat the tests. What is the best course of action to follow?
a. report results immediately by phone, emphasizing that the tests were run in duplicate, and the controls are within range
b. request a new specimen and repeat the procedures using freshly diluted controls
c. repeat the procedures on an instrument that detects clot formation electromechanically
d. inform the physician that accurate results are impossible
C
- which coagulation factors are referred to as “vitamin K dependent”?
a. I,V,VIII,XIII
b. II,V,IX,XII
c. II,VII,IX,X
d. xixii,fletcher, Fitzgerald
C
- a severe vitamin K deficiency will affect all of the following except:
a. fibrinogen
b. stable factor
c. Christmas factor
d. protein C
A
Stable factor: VII
- a patient with coronary artery disease is admitted to the hospital with venous thrombosis. What medication can be administered that will lyse the clot?
a. aspirin
b. Coumadin
c. heparin
d. tissue plasminogen activator
D
- reversal of a heparin overdose can be achieved by:
a. vitamin K
b. protamine sulphate
c. antithrombin III
d. Warfarin
B
Reversal of Coumadin would require Vitamin K. Monitor heparin with PTT (intrinsic) and Coumadin with PT (extrinsic)
- D-dimers are degradation products of:
a. non cross-linked fibrin
b. cross-linked fibrin
c. fibrinogen
d. plasmin
B
- a donor indicates he has taken 2 aspirin tablets per day for the last 36 hours. The unit of blood:
a. may not be used for pooled plt concentration preparation
b. should not be drawn until 36 hours after cessation of aspirin ingestion
c. may be used for pooled plt concentration preparation
d. may be used for red cells, and fresh frozen plasma production, but the plts should be discarded
C: pooled platelets is okay but not for aphaeresis I’m assuming?
Cannot take platelets if donor has taken aspirin in the last 48hours. Inhibits platelet aggregation.
- which of the following is least likely to transmit hepatitis?
a. cryoprecipitate
b. RBC
c. plasma protein fraction
d. plts
C
- FFP, when properly collected and stored, provides all the following except:
a. factor V
b. factor VIII
c. factor IX
d. plts
D
- all of the following components must be routinely irradiated except:
a. RBC for intrauterine transfusion
b. RBC for exchange transfusion
c. plts for an immunosuppressed patient
d. plts from an HLA compatible donor
B
Intrauterine: RBC from donor injected into fetus
Exchange transfusion ex: hemolytic disease of the newborn, sickle cell anemia
- the addition of adenine in an anticoagulant-preservative formulation aids in:
a. maintaining ATP levels for red cell viability
b. maintaining plt function in stored blood
c. reducing the plasma K+ levels during storage
d. maintaining 2,3DPG levels for oxygen release to the tissues
A
- the pilot tubes for donor unit# 3276 break in the centrifuge. You should:
a. label the blood using the donor’s previous records
b. discard the unit because processing procedures cannot be performed
c. discard the red cells and salvage the plasma for fractionation
d. remove sufficient segments to complete donor processing procedures
D
- the temperature range for maintaining red blood cells and whole blood during shipping is:
a. 0-4C
b. 1-6C
c. 1-10C
d. 5-15C
C
- during the preparation of plt concentrate the hermetic seal of the primary bag is broken. The red blood cells:
a. must be discarded
b. must be labelled with a 21-day expiration if collected in CPD
c. must be labelled with a 24-hour expiration date
d. may be glycerolized within 6 days and stored frozen
C
- the blood bank procedures manual must be:
a. revised annually
b. revised after publication of each new edition of AABB standards
c. reviewed prior to a scheduled inspection
d. reviewed annually by an authorized individual
D
- which of the following weak D donor units should be labelled RH-positive?
a. weak D due to transmissible genes
b. weak D as position effect
c. weak partial D
d. all of the above
D
- which of the following tests on donor red blood cells must be repeated by the transfusing facility when the blood was collected and processed by a different facility?
a. confirmation of ABO group and Rh type of blood labelled D-negative
b. confirmation of ABO group and Rh type
c. weak D on D-negative
d. antibody screening
A
- which of the following blood groups reacts with least strongly with an anti-H produced in an A,B individual?
a. group O
b. group A2B
c. group A2
d. group A1
D
Group O and A2 not only have the most H antigen of all the groups, but also have a molecular structure that leaves divide very accessible to anti-H
Look into this? Answer should be B
- a Bombay (Oh) individual’s blood specimen can be differentiated from blood specimens of normal group O persons by the:
a. cells giving a negative reaction with anti-A,B
b. serum containing anti-H
c. cells giving a positive reaction with Ulex europaeus
d. cells giving negative reaction with Dolichos biflorus
B
Ulex europaeus: demonstrates the presence and strength of expression of the H antigen
Dolichos biflorus: differentiate between A1 and A2 RBC’s
- the secretor locus is linked to which blood group locus?
a. Duffy
b. Kell
c. Lewis
d. Lutheran
D
Secretor: secretes blood type antigen into body fluids like the saliva, and mucus
- if a person has the genetic makeup Hh, AO, LeLe, see, what substance will be found in the secretion?
a. A substance
b. H substance
c. Lea
d. Leb
C
- a serum containing anti-k is not frequently encountered. This is because:
a. people who lack the k antigen are rare
b. people who possess the k antigen are rare
c. the k antigen is not a good immunogen
d. Kell null people are rare
A
218.
- which of the following is a characteristic of Kidd antibodies?
a. usually IgM antibodies
b. corresponding antigens are destroyed by enzymes
c. usually strong and stable during storage
d. often associated in delayed transfusion reactions
D
- all of the following statements are true of anti-Fya and anti-Fyb except:
a. are clinically significant
b. react well with enzyme treated panel cells
c. cause hemolytic transfusion reactions
d. cause a generally mild hemolytic disease of the newborn
B
Duffy and MNSs are broken down by enzyme treatment and enhance Rh, Kidd, Lewis, and ABO blood groups.
- a patient had an anti-E identified in his serum 5 years ago. His antibody screening test is now negative. To obtain suitable blood for transfusion, the best procedure is to:
a. type the patient for the E antigens as an added part to the crossmatch the E-negative procedures
b. type the donor units for the E antigens and crossmatch the E negative procedure
c. crossmatch donors with the patient’s serum and release the compatible units for transfusion
d. perform the crossmatch with enzyme treated donor cells, since enzyme treated red cells react better with Rh antibodies
B
- a patient’s red blood cells are being typed for Fya antigen. Which of the following is the proper cell type of choice for a positive control of the anti-Fya reagent?
a. Fy(a+b-)
b. Fy(a+b+)
c. Fy(a-b+)
d. Fy(a-b-)
B
- which of the following antibodies has been clearly implicated in transfusion reactions and hemolytic disease if the newborn
a. anti-I
b. anti-K
c. anti-Lea
d. anti-N
B
- enzymes are often used to aid in the identification of antibodies. Which of the following antibodies is primarily IgG, is best detected at the AHG phase, can cause hemolytic transfusion reactions and hemolytic disease of the newborn, and the corresponding antigen is destroyed by proteolytic enzymes:
a. anti-D
b. anti-S
c. anti-K
d. anti-Jka
B
- often when trying to identify a mixture of antibodies it is useful to neutralize one of the known antibodies. Which one of the following antibodies is neutralizable?
a. anti-D
b. anti-Jka
c. anti-Lea
d. anti-M
C
- which of the following antibodies does not match the other’s in term of optimal reactive temperature?
a. anti-Fya
b. anti-Jkb
c. anti-N
d. anti-U
C
- which of the following antigens is destroyed by proteolytic enzymes?
a. E
b. Lea
c. K
d. M
D
- which set of antibodies could you possibly find in a patient with no history of pregancy or transfusion?
a. anti-I, anti-s, anti-P1
b. anti-Leb, anti-A1, anti-D
c. anti-M, anti-c, anti-B
d. anti-P1, anti-Lea, anti-I
D
- In which of the following instances may mixed-field agglutination be observed?
a. direct antiglobulin test (DAT) result of patient undergoing delayed hemolytic transfusion reaction
b. IAT result of patient who has anti-Lea
c. DAT result of patient on high doses of a-methyldopa
d. typing result with anti-A of patient who is A2 subgroup
A
- the ABO serum grouping may not be valid when:
a. the patient has hypogammaglobulinemia
b. IgM alloantibodies are present
c. cold autoantibodies are present
d. all of the above
D
- which of the following is generally detected at the indirect anti globulin phase of testing?
a. anti-Jka
b. anti-M
c. anti-P1
d. anti-I
A
- A group A, D negative obstetric patient with anti-D (titre 256) is carrying fetus who needs an intrauterine transfusion. which of the following units should be chosen?
a. group A, D-negative RBC
b. group A, D-negative whole blood
c. group O, D-negative RBC
d. group O, D negative whole blood
C
- which of the blood groups systems is associated with antibodies that are generally IgM?
a. Rh
b. Duffy
c. Kell
d. Lewis
D
- false negative results at the IAT phase of antibody screening test are most likely due to:
a. excessive washing of the red cells
b. inadequate washing of the red cells
c. warm autoantibody present in the patient’s serum
d. failure to allow the blood to clot properly
B
- at the end of an anti globulin test, IgG coated control cells are added to the negative tests and centrifuged. If agglutination occurs, this means the:
a. test is valid
b. antiglobulin reagent was neutralized
c. cells were not washed thoroughly
d. control cells are contaminated
A
- a resident physician hand-delivers a blood sample, drawn by the attending physician, for pre-transfusion testing from a patient who is difficult to draw. The sample is unlabelled. One should:
a. discard the sample and request that the resident obtain a new sample, adhering to proper guidelines for labelling
b. label the specimen with the information the resident provides
c. label the specimen with information from the accompanying transfusion request form
d. request the sample be returned to the nursing station to be labelled
A
- a specimen of blood is received in the blood bank with request slips for transfusion. The tube has the patient’s first and last name and medical records identification number on the label. what else must be on the tube label?
a. patient’s room #
b. date of phlebotomy
c. initials of phlebotomist
d. attending physician’s name
B
- a patient with an anti-K and an anti-Jka in her plasma needs 2 units of RBC for surgery. How many group-specific units would need to be screened to find 2 units of RBC?
a. 6
b. 10
c. 20
d. 36
B
- enterotoxin produced by staphylococcus aureus is responsible for causing:
a. carbuncles
b. enterocolitis
c. scalded skin syndrome
d. toxic shock syndrome
B
- a fermentative gram negative bacillus that is oxidase +, motile, grows well on MAC is:
a. aeromonas hydrophily
b. pseudomonas aeruginosa
c. xanthomonas maltophilia
d. yersinia enterocolitica
A
Yersinia is oxidase negative and is only motile at 22C but grows on MAC as a NLF or LLF.
- the etiologic agent of primary atypical pneumonia is:
a. chlamydia psittaci
b. streptococcus pneumonia
c. corynebacterium diphtheriae
d. mycoplasma pneumonia
D
- streptococcus progenies organisms are best presumptively identified using:
a. bacitracin disk
b. ONPG disk
c. PYR disk
d. optochin disk
C
- an example of an oxidase-positive, glucose non fermenting organism is:
a. Enterobacter species
b. E. coli
c. Klebsiella species
d. Pseudomonas aeruginosa
D
- Nocardia asteroides infections in humans characteristically produce:
a. draining cutaneous sinuses
b. carbuncles
c. septic shock
d. serous effusions
A
- the etiologic agent commonly associated with septicaemia and meningitis of newborns is:
a. streptococcus progenies
b. streptococcus pneumonia
c. streptococcus agalactiae
d. streptococcus bovis
C
- which of the following is the most commonly isolated species of Bacillus in opportunistic infections such as bacteria, post-traumatic infections of the eye, and endocarditis?
a. B. subtilis
b. B licheniformis
c. B. cereus
d. B. circulans
C
- the etiologic agent of whooping cough is:
a. Brucella suis
b H. ducreyi
c. Francisella tularenis
d. Bordetella pertussis
D
- an important characteristic of N. gonorrhoeae or the infection it produces is:
a. gram stain of the organism shows gram-positive diplococci
b. a symptomatic infections are common in males
c. gonorrhoea is a disease of humans and domestic animals
d. nonpiliated strains are avirulent
D
- a causative agent of the form of conjunctivitis known as pink eye is:
a. H. influenzae biotype III
b. Moraxella lacunata
c. chlamydia trachomatis
d. Listeria monocytogenes
A
- Acinetobacter species are similar to Neisseriaceae with the notable exception that they are:
a. gram negative coccoid organisms
b. growth on blood and chocolate agar
c. oxidase negative
d. glucose positive
C
- hemolytic uremic syndrome is a complication after infection with:
a. E. coli O157:H7
b. Shigella sonnei
c. Vibrio cholera O1
d. salmonella typhi
A
- identify the fermentative agent that may infect reptiles or fish as well as humans when they are exposed to contaminated soil or water:
a. Edwardsiella
b. Aeromonas
c. Chromobacterium
d. Cryseobacterium
B
- which of the following has a negative oxidase test:
a. aeromonas
b. hafnia
c. vibrio
d. pseudomonas
B
- the symptom of diffuse, water diarrhea that produces relatively clear stool containing mucus flecks (rice water stool) is most closely associated with an infection caused by:
a. E. coli
b. shigella dysenteriae
c. vibrio cholerae
d. yersinia enterocolitica
C
- all of the following describe Actinetobacter species except:
a. commonly susceptible to most antimicrobials
b. generally coccobacillary in morphology
c. oxidase negative
d. infections associated with use of medical devices
A
- explosive watery diarrhea with severe abdominal pain, after eating raw shellfish is most characteristic of:
a. H. pylori
b. vibrio parahemolyticus
c. shigella dysenteri
d. campylobacter jejuni
B
- a clinical problem has emerged concerning infections after prosthetic heart valve insertion or other cardiac procedures with MRSA strains of:
a. S. epidermidis
b. serratia marscescens
c. streptococcus salivarius
d. enterococcus faecalis
A
- Shigella sonnei is differentiated from the other species by:
a. its ability to ferment lactose
b. its positive phenylalanine reaction
c. its negative oxidase reaction
d. its ability to demonstrate motility at 42C
A
- Which one of the following is not appropriate when describing S. pneumoniae?
a. lancet-shaped, gram-positive diplococcus
b. bile-resistant
c. alpha hemolytic
d. encapsulated, with an antiphagocytic polysaccharide capsule
B
Lysed by bile
- which of the following would be appropriate when discussing H. influenzae?
a. the etiologic agent of influenza
b. most infections caused by capsular serotype b
c. always sensitive to ampicillin
d. common cause of bacterial pneumonia
B
- Enterococcus faecium is characteristically:
a. inhibited by the presence of bile in the culture media
b. able to grow in the presence of high concentration of salt
c. PYR negative
d. sensitive to penicillin
B
- a sputum specimen from a suspected case of lobar pneumonia patient shows on gram stain the presence of many WBCs and many gram-positive cocci, which are primarily in diplococci. Which of the following statements would be appropriate, given these findings on a smear?
a. a PYR test should be performed on the culture isolate
b. an ELEK test should be performed on the culture isolate
c. a CAMP test should be performed on the culture isolate
d. an optochin test should be performed on the culture isolate
D
- an identifying characteristic of S. aureus is:
a. DNase negative
b. negative mannitol fermentation reaction
c. growth inhibition in presence of increased salt
d. positive coagulase test
D
- which of the following is a correct statement concerning Campylobacter jejuni?
a. isolated best at 24C
b. a leading cause of bacterial diarrhea worldwide
c. hydrogen sulphide positive
d. catalase negative
B
Isolated best at 37-42C
- all the following statements about haemophilus sp. are true except:
a. the preferred culture medium is SBA
b. small, pleomorphic, gram-negative coccobacilli
c. obligate parasites
d. many are found as normal flora in the human respiratory tract
A
- which of the following is not a selective media for primary isolation of Bordetella pertusis?
a. modified Skirrow’s medium
b. Regan-Lowe
c. Bordet-Gengou
d. Modified Jones-Kendrick charcoal
A
- a gram-negative bacillus was recovered from the urine of a child with a history of recurrent UTI’s. The organism was oxidase negative, lactose negative, urease positive, and motile. The most likely identification of this agent would be:
a. proteus mirabilis
b. E. coli
c. P. aeruginosa
d. K. pneumoniae
A
- which of the species of pasteurella is associated with human infections?
a. aerogenes
b. haemolytica
c. pneumotropica
d. multocida
D
- which of the following genera is the most commonly associated with bacterial vaginosis?
a. Gardnerella
b. Listeria
c. Eikenella
d. Capnocytophaga
A
- Swimmer’s ear, a form of external otitis media, is commonly caused by:
a. Mycobacterium marinum
b. Pseudomonas aeruginosa
c. Streptococcus pneumoniae
d. Haemophilus influenzae
B
- which of the following is not a correct statement regarding blood culture?
a. collection of 10-20ml per culture for adults is recommended
b. two or three blood cultures recommended as optimum
c. volume of blood cultured more critical than timing of culture
d. blood drawn for culture may be allowed to clot
D
- colonies of Listeria monocytogenes on SBA most closely resemble colonies of:
a. S. agalactiae
b. Corynebacterium diphtheria
c. Rhodococcus equi
d. Haemophilus influenzae
A
- the most common etiologic agent of infections associated with the surgical insertion of prosthetic devices such as artificial heart valves and CSF shunts is:
Staphylococcus epidermidis
- one of the most common etiologic agents of uncomplicated cases of cystitis is:
E. coli
- the characteristic growth pattern known as satelliting Is associated with:
Haemophilus influenzae
- solubility in the presence of sodium deoxycholate is characteristic of:
Streptococcus pneumoniae
- an anaerobically incubated blood agar plate shows colonies surrounded by an inner zone of complete red cell lysis and an outer zone of incomplete cell lysis that gives a discoloured appearance. The most likely rapid presumptive identification of this isolate would be:
Clostridium perfringens
- a cervical mucosal abscess specimen was sent to the laboratory for bacteriology examination. The culture of this sample grew an anaerobic gram-negative bacillus that was inhibited by bile, pigmented brown, and was negative for indole production, positive for glucose, sucrose and lactose fermentation. This isolate would most likely be:
Prevotella melaninogenicus
- obligately anaerobic, gram-negative bacilli, recovered from the abdominal wound, were found to be resistant to penicillin. Growth of this organism was not inhibited in the presence of bile. What is the most likely identification of this isolate:
Bacteroides fragilis group
- a filamentous gram-positive rod recovered from an aspirate of a closed chest abscess. It grew only under anaerobic conditions and was not acid-fast. What is the most likely presumptive identification of the isolate seen?
Actinomyces Israelii
