ASCP Questions Review

Question 1

How does oral contraceptive change iron stores levels?

Answer 1

Iron stores are higher

Ferritin is higher in oral contraceptive users

Question 2

PT, APTT and TT are all abnormal, what is most likely the cause?

Answer 2

Afibrinogenemia

Afibrinogenemia, Dysfibfogenemia, DIC, Heparin contamination and Thrombin inhibitors can cause these results

Question 3

A patient’s plasma was screened for alloantibodies and was positive for anti K (big K). What percentage of ABO compatible blood units would be K antigen negative and can be chosen for transfusion?

Answer 3

91
(Big K is a low frequency antigen. k (small k) however is 99.9% positive)
X = number of donors required
frequency of donors negative for the antigen
(expressed as a decimal)
where X = minimum number of donors that must be antigen typed

Question 4

What are pappenheimer bodies?

Answer 4

Iron Particles 
(pappenheimer bodies are iron particles seen in groups and varying size. May be seen in Sideroblastic anemias, hemoglobinopathies)

Question 5

How do you differentiate between Yersinia Pestis and Y. Enterocolitica ?

Answer 5

Motility

Y.Pestis is non motile and Urease negative while E.Enterocolitica is positive for both

Question 6

D-Dimer test is normal, but FDP (fibrin degradation products) is abnormal. What does this mean?

Answer 6

Primary Fibrinogenolysis
(D-dimer is positive when actual clot has formed and then broken. Fibrinogen degradation products can present when there is no clot but a primary fibrinogenolysis is going on)

Question 7

What factor mediates formation of Prothrombin to Thrombin?

Answer 7

Xa

Activated factor X acts on Prothrombin ( Factor II) to form Thrombin

Question 8

What test is done when exposure to pesticides is suspected?

Answer 8

Cholinesterase

Cholinesterase is used to detect and diagnose pesticide exposure and or poisoning

Question 9

If hgb= 12 g/dl and Hct = 36% calculate MCHC

Answer 9

33
MCHC (g/dL) = (Hgb ÷ PCV) x 100
or
MCHC (g/dL) = (Hgb ÷ HCT) x 100

Question 10

Which of the following bacteria is H2S negative?

• Citrobacter spp
• Salmonella typhi
• Proteus spp.
• Salmonella paratyphi A

Answer 10

Salmonella Paratyphi A

Paratyphi A isolates on TSI/KIA are usually K/AG and do not produce H2S

Question 11

If an individual is a nonsecretor (se se) with Lewis phenotype Le(a+b-) what antigen will be detected in his or her fluids?

Answer 11

Le a

Le a is the only antigen that can be secreted in nonsecretor

Question 12

A bacteria that is A/A on TSI agar is grown on HK (Hekteon) agar. What color do you expect the agar turn to?

Answer 12

Yellow- Orange
(Hekteon agar is primarily used to isolate and differentiate Salmonella and Shigella spp. The HK plates contain sugars such as lactose and sucrose, none of which can be used by either Shigella or Salmonella, but the medium also includes peptone which can be used as a carbon source. Since most bacteria can use the sugars in reference to peptone, these bacteria acidify the medium and turn the pH indicator yellow or red. Peptone metabolism by Shigella and Salmonella alkalises the medium, turning the pH indicator to blue)

Question 13

What does caffeine benzoate do in Jendrassik- Grof method of measuring bilirubin?

Answer 13

Acts as an accelerator
(In Jendrassik-Grof method : 1. (for conjugated bilirubin) a fasting sample of serum or plasma is collected and acidified by the addition of hydrochloric acid. Ehrlich’s diazo reagent is added so that the conjugated bilirubin begins forming blue azobilirubin. After 10 minutes the reaction is stopped and the amount of azobilirubin in the sample is measured. 2. (for total bilirubin) to an acidified fasting sample as in the previous method, caffeine benzoate is added as an accelerator for the unconjugated bilirubin to form azobilirubin. When the reaction is stopped, the azobilirubin in the sample thus represents the total of both conjugated and unconjugated bilirubin)

Question 14

Which solution is used for measurement of HDL?

Answer 14

Heparin Manganese

Heparing manganese is a precipitation factor used in measurement of HDL

Question 15

What test is used to identify Hairy Cell leukemia?

Answer 15

TRAP
(Tartrate-resistant acid phosphatase (TRAP) activity is present in the leukemic cells of most patients with hairy cell leukemia)

Question 16

5HIAA test is used for what disease?

Answer 16

Carcinoid tumors 
(5HIAA is a test usually done on 24 hour urine specimen for carcinoid tumors)

Question 17

What factor is deficient in Hemophilia B?

Answer 17

IX

Factor IX causes Hemophilia B, also known as Christmas disease

Question 18

What is the specimen of choice for Rotavirus?

Answer 18

Stool

Rotavirus A and C can be detected in stool specimen. Real time PCR is used

Question 19

Which statement is NOT true regarding von Willebrand factor?

• Is deficient in Hemophilia A
• vW:RCo is deficient in von Willebrand disease
• It is required for platelet adhesion to collagen
• It consist of fractions vWF: RCo and vWF:Ag

Answer 19

Is deficient in Hemophilia A

Hemophilia A is factor VIII deficiency. Both factor vW:RCo and vW;Ag are deficient in von Willebrand Disease.

Question 20

A 4 year old peripheral blood shows cells with increased N/C ratio and cells with 2 nucleoli.The nuclei of cells are indented and irregular. What is the most likely diagnosis?

Answer 20

ALL

Acute Lymphoblastic Leukemia is the most common type of leukemia in children. The age in the test is a hint

Question 21

The bacteria pictured was isolated from a clinical specimen and cultured in absence of oxygen. The gram stain from Chocolate agar shows long rods with tapered ends. Choose the most likely candidate.

Answer 21

Fusobacterium
(Tapered ends is characteristic of Fusobacterium. It is frequently found in dental plaque of humans and is spindle shaped)

Question 22

What blood group reagent deteriorate faster while in use?

Answer 22

MNS

MNS reagent will deteriorate faster than the other blood types

Question 23

A gram stain from abdominal abscess shows gram negative rods. It grows anaerobically in presece of Bile Esculin. Which choice is the most likely Identification?

Answer 23

Bacteroides Fragilis
( Actinomyces is gram positive. Among Bacteroides, Fusobacterium, Porphyromonas and Prevotella, only Bacteroides can grow on Bile Esculin agar)

Question 24

What can cause false positive for urobilinogen on urine strips?

Answer 24

Prophobilinogen
(Any chemical that can react with Ehrlich’s reagent can cause a false positive reaction, such as porphobilinogen and sulfonamides. Exposure to light for a long period and formalin may cause false negative results)

Question 25

If the life span of red blood cells are shortened, how does the urine bilirubin levels change?

Answer 25

Urine bilirubin is negative, urine urobilinogen is increased
(When life span of red blood cells is shortened, production of total bilirubin will increase. The increase is mostly due to unconjugated bilirubin which will not appear in urine. Urine urobilinogen, however, will increase)

Question 26

Large, circular, gray and smoth colonies are observed on a blood agar plate with swarming motility. What test to do next?

Answer 26

Indole
(Swarming colonies is charactersitic of Proteus. To differentiate between Proteus Vulgaris and Proteus Mirabilis indole test is performed. P.Vulgaris is indole positive)

Question 27

Which mycobacterium is found in tap water?

Answer 27

M. gordonae

M.gordonae is ubiquitous and it is most commonly isolated from soil and water

Question 28

What is the specimen of choise for FK506 (Tacrolimus, Cyclosporin and Sirolimus)?

Answer 28

Lavender Top
(Tacrolimus, Cyclosporine and Sirolimus are immuno-suppressant drugs and are tested using whole blood collected in EDTA tubes)

Question 29

In what blood group type expression of antigens is weakened or in some cases negative during pregnancy?

Answer 29

Lewis

Pregnant women transiently exhibit Le(a-b-) phenotype and Lewis antibodies are sometimes formed during pregnancy

Question 30

Which is true regarding weak D phenotype?

Answer 30

All the epitopes are present but under expressed
(Weak D red cells have the D antigen, but have fewer D antigens per cell than normal Rh positive cells. Weak D phenotype blood is negative in immediate spin phase. A change in expression of D antigen is called Partial D and is result of a mutation in RHD gene.)

Question 31

If volume of fetal bleed is 62mL, how many vials of RhIg should be given to the mother?

Answer 31

3
(One 300 ml vial of RhIG will protect against 30 ml of D-positive fetal blood.When the number to the right of the decimal point is less than 5, round down and add one dose. When the number to the right of the decimal point is greater than 5, round up and add one dose. 62/30ml =2.06 => 2+1=3)

Question 32

What is Fletcher’s media used for?

Answer 32

Leptospira spp.

Fletecher’s media is a semi solid medium recommended for cultivation of Leptospira spp

Question 33

What are Heinz Bodies made of?

Answer 33

Denatured Hemoglobin
 (Heinz Bodies are denatured hemoglobin. They are visible with Supravital stains. Heins Bodies are seen in G6PD deficiency, Beta-talassemia and Hgb H disease)

Question 34

On a automated coagulation analyzer, PT controls are in range but PTT controls are out of range. New controls produce same results, What do you do?

Answer 34

CaCl2 might have been added to APTT reagent accidentally, change reagents and repeat
(Recombiplastin and readiluent are components of the kit for automated PT test, not APTT. It is a CLIA violation to keep repeating test till it comes in range. CaCl2 an Phospholipid are two vials in automated APTT kits and come ready to use)

Question 35

What type of red cells is shown and in what condition do you see them?

Answer 35

Stomatocytes in liver disease

Stomatocytes are seen in alcoholic liver disease

Question 36

In Biliary obstruction, how does the urine bilirubin and urobilinogen change ?

Answer 36

Urine bilirubin is positive, urobilinogen is decreased or negative
(In biliary obstruction, bilirubin does not reach duodenum where it would be reduced to urobilinogen and then recirculate into the blood, therefore urobilinogen in the urine will be negative or decreased. When bile duct is obstructed, conjugated bilirubin will increase in blood and appear in urine)

Question 37

In hemolytic anemia, how does bilirubin levels change?

Answer 37

Unconjugated bilirubin increase, urine urobilinogen increase
(In conditions such as hemolytic disease of the newborn, hemolytic anemias, and congestive heart failure the prehepatic increase in uncojugated bilirubin causes increase in both uncojugated bilirubin and urine urobilinogen)

Question 38

How do you calculate coefficient of variation?

Answer 38

SD / Mean X 100

Question 39

What is the reagent used in sickle cell solubility test?

Answer 39

Sodium Dithionite 
(The solubility test is the most common screening test for sickle cell or presence of HbS. It is based on the relative insolubility of HbS when combined with a reducing agent such as sodium dithionite. When anticoagulated blood is mixed the reducing agent, the red cells will lyse due to the presence of saponin and the hemoglobin in the red cells will be released. If HbS is present, it will form liquid crystals and give a cloudy or turbid appearance to the solution. If HbS is not present, the solution will appear transparent, with rare exceptions)

Question 40

In Hashimoto’s thyroiditis, how do the levels of T4 and TSH change?

Answer 40

TSH is high and T4 is low
(Hashimoto’s thyroiditis is an autoimmune condition in which the body attacks and destroys its own thyroid gland. T4 levels fall while TSH increases trying to elevate T4 levels)

Question 41

If RPR test is positive and ABS-FTA test is negative, what is the interpretation of the results?

Answer 41

False positive RPR, repeat in 2 weeks

The most likely explanation is a false positive for RPR

Question 42

What can make CSF appear cloudy?

Answer 42

Crystals
(Presence of crystals in CSF can give it a cloudy appearance. WBC up to 5 per mm3 and Proteins up to 45 mg/dl are normal)

Question 43

Target cells in peripheral blood can cause which of the following choices when automated methods are used?

Answer 43

High WBC count
(Target cells are seen in liver disease, thalassemia, Hgb C disease and splenectomy among other conditions. Target cells are more resistant to lysis because of increased surface:volume ratio and because of that can increase the number of lymphocytes and total WBC count)

Question 44

Calculate the anion gap if Na= 138 mEq/L Cl-= 102 mEq/L HCO3-= 27 mEq/L

Answer 44

9

Anion gap = [Na] - ([Cl-] + [HCO3-]) You need to be able to calculate anion gap, memorize this formula

Question 45

What are Howell-Jolly bodies?

Answer 45

DNA fragments
(HJ bodies are DNA fragments. They are usually pitted by splenic cells. HJ bodies may be seen in alcoholism, post splenectomy, Beta-talassemia major, sever hemoytic anemias and megaloblastic anemia)

Question 46

What is another name for Cooley’s anemia?

Answer 46

Thalassemia major

Thalassemia Major or Cooley’s anemia. This is the most severe form of beta thalassemia

Question 47

Beta- hCG is a marker for what disease?

Answer 47

Testicular cancer

Beta-hCG helps to diagnose Testicular (germ cell) tumors

Question 48

If total cholesterol is 220mg/dl, HDL is 45 mg/dl and triglycerides is 250 mg/dl, what is the concentration of LDL?

Answer 48

125

Friedewald (1972) Formula: LDL =TC - HDL - TG/5.0 (mg/dL)

Question 49

Enzymes enhance which blood group systems?

Answer 49

ABO, Rh, Kidd, Lewis
(ABO, Rh, Kidd, Lewis, I/i and P antigen expression enhance after treating cells with enzymes. Enzymes have no effect on Kell antigens and decreases expression of MNS and destroys Duffy antigens)

Question 50

What is Azetomia?

Answer 50

Increased BUN 
((azot, "nitrogen" + -emia, "blood condition") is a medical condition characterized by abnormally high levels of nitrogen-containing compounds (such as urea, creatinine, various body waste compounds, and other nitrogen-rich compounds) in the blood)

Question 51

Which of the following is characterized by hypotension due to systemic infection that does not respond to fluid resuscitation (an attempt to replenish body fluid)?

• Systemic Inflammatory response syndrome
• Sepsis
• Septic Shock
• Bacteremia

Answer 51

Septic Shock 
(Septic shock is the correct answer. Severe sepsis progresses to septic shock if the hypotension caused by systemic infection does not respond to fluid resuscitation. Septic shock results from the by-products of growing organisms acting on the host body and the host body reacting to the by-products. Gram negative rods cause the most serious conditions of septic shock. Disseminated intravascular coagulation (DIC) is a complication of septic shock.)

Question 52

Which gram positive bacilli will show a positive result for urease?

• lactobacillus spp
• actinomyces naeslundii
• erysipelothrix spp
• Cutibacterium acnes

Answer 52

Erysipelothrix
(Actinomyces naeslundii will give a positive result for urease.
The other Gram positive rods that are listed; Lactobacillus species, Erysipelothrix species, and Cutibacterium (Propionibacterium) acnes will all have an negative urease test)

Question 53

Sulfosalicylic acid (SSA) can be used to confirm the result of which test in a urine chemical reagent strip?

Answer 53

Protein
(The SSA reaction is used to detect protein in the urine. Unlike the protein test on the urine chemical reagent strip, the SSA reaction will detect albumin and globulins, and Bence-Jones proteins. This principle is based on the acidification of proteins which causes turbidity and can be measured based on protein concentration present)

Question 54

Can you use an alcohol wipe to cleanse the venipuncture site prior to obtaining a sample for ethanol?

Answer 54

No, alcohol wipes must be avoided when testing for ethanol levels
(The correct answer is no, alcohol wipes must be avoided. This is because the alcohol can interfere with the levels of ethanol and cause falsely-elevated levels.
Letting the site dry does not prevent interference and alcohol wipes must not be used, even if they contain other alcohols since the breakdown products are similar; other cleansers can be used to sanitize the site when looking for alcohol/ethanol determinations)

Question 55

What is the glomerular filtration rate for a patient with a serum creatinine of 2 mg/dL, if the urine creatinine was 124 mg/dL and the urine volume was 2.2 L/24 hrs?

Answer 55

95 mL/min
(Creatinine Clearance = (urine creatinine X urine flow rate) / plasma creatinine; where urine flow rate = volume in mL /24 hours x h/60 min))
In this case = creatinine clearance = 124 X (2200/24 x hour/60) / 2 = 94.7 or 95 mL/min

Question 56

Adult cestodes utilize which body part to attach to the human intestine?

Answer 56

Suckers
(The suckers serve as the mechanism by which adult cestodes obtain nourishment. Attachment to the human intestine allows feeding to occur)

Question 57

On occasion in cases of heavy infection, rhabditiform nematode larvae, measuring up to 1.5 cm long, may be observed in mounts prepared from stool specimens. A presumptive species identification can be made by microscopically observing the buccal cavity as illustrated in the photograph. What is the most likely species of this nematode?

Answer 57

Necator Americanus 
(Necator americanus is one of the hookworms. This species can be identified by observing the rhabditiform larvae that characteristically have a long buccal cavity as illustrated in the photograph.
Strongyloides stercoralis rhabditiform larvae have a short buccal cavity. On further examination, a prominent genital primordium may also be observed about one-third the distance from the tail)

Question 58

Antibodies within which of the following blood group systems are known to result in severe hemolytic transfusion reactions, but are not always detected during pre-transfusion testing in the blood bank?

Answer 58

Kidd
(Kidd is the most common cause of delayed transfusion reactions. The antibody titer for Kidd can drop to undetectable levels several months after primary exposure to the antigen. Upon subsequent exposure to the antigen, a robust antibody response and hemolysis of the offending donor red cells occurs. This is also referred to as an anamnestic response)

Question 59

What is the minimum acceptable hematocrit level for a male that wants to donate double RBC units through RBC apheresis?

Answer 59

33%
(The minimum acceptable hematocrit level for a male or female to participate in a double RBC apheresis program is 40%. The hematocrit level can’t be determined using a copper sulfate method, and MUST be a quantitative method.

For a male donor wanting to donate a single unit of whole blood, the minimum acceptable hematocrit level is 39% or the hemoglobin equivalent of 13 g/dL.

For a female donor wanting to donate a single unit of whole blood, the minimum acceptable hematocrit level is 38% or a hemoglobin of 12.5 g/dL.

Persons wanting to make an autologous donation must have a hematocrit of 33% or greater, or a hemoglobin of 11 g/dL or greater)

Question 60

Bacterial contamination is MOST likely in which of the following blood products?

• packed red blood cells
• frozen red blood cells
• platelets
• fresh frozen plasma

Answer 60

• platelets
  (Bacterial contamination of platelets is most likely because they are stored at room temperature. The estimated rate of bacterial contamination in platelets is around 10%.
  Bacterial contamination is possible in packed red blood cells stored in the refrigerator, but the estimated rate of bacterial contamination is only around 0.2%
  Frozen red blood cells are not likely to have bacterial contamination.
  Fresh frozen plasma is not likely to have bacterial contamination)

Question 61

Polymerase chain reaction (PCR) copies DNA through repeated cycles of three basic steps. What is the correct order of these steps?

Answer 61

Denaturation, annealing, extension
(Extraction of the DNA from the clinical sample occurs before the initiation of PCR. Once extracted, the sample is heated to a temperature at which the strands of DNA separate (denaturation). Next, the temperature is lowered and the primers attach (anneal) to their complementary targets. Lastly, the temperature is raised and new strands of DNA are synthesized (extension), utilizing free nucleotides in the reaction mixture)

Question 62

All of the following observations are consistent with the laboratory identification of Cryptococcus neoformans, EXCEPT:

• Colonies that appear mucoid on primary isolation culture medium.
• Negative urease test.
• Cornmeal agar morphology displaying spherical, irregular cells with no pseudohyphae.
• Presence of capsular material.

Answer 62

-Negative Urease Test
(Cryptococcus neoformans would produce a rapidly positive urease test. All the remaining observations are consistent with the laboratory identification of C. neoformans.
Upon observing mucoid appearing colonies on a primary isolation culture medium, perform a rapid urease test and set up a cornmeal agar preparation.
If the urease test is rapidly positive, observe the cornmeal agar morphology. If pseudohyphae are absent, and particularly if the yeast cells are spherical, irregular in size and widely separated (presence of capsular material), inoculate the surface of a bird seed agar plate with a small portion of the unknown colony.
If a brown pigment is produced within 48-72 hours, a definitive identification of Cryptococcus neoformans can be made)

Question 63

The test used for the identification of specific capsular serotypes of Streptococcus pneumoniae is

Answer 63

Quellung
(The Quellung test is performed by mixing a light suspension of the suspected organism with a small amount of type specific antiserum on a glass slide and observing for the “swollen” appearance of the capsule to detect serogroup matches of S. pneumoniae. This process both identifies and serotypes the isolate)

Question 64

Infections with this organism typically either present as primary septicemia or wound infections. Septicemia likely occurs after the organism is ingested while consuming shellfish. Wound infections are associated with some type of aquatic exposure. What organism does this describe?

Answer 64

Vibrio Vulnificus
(Vibrio vulnificus is a halophilic vibrio that causes wound infections in persons having contact with contaminated water, and has a distinct propensity to invade the blood stream and cause septicemia, often with a fatal outcome. It is thought that V. vulnificus invades the blood stream following consumption of contaminated shellfish, especially raw oysters)

Question 65

Platelets should be stored at what temperature?

Answer 65

20-24 degrees celsius
Platelets should be stored at 20-24 degrees Celsius with continuous gentle agitation. They should be infused within 4 hours after the seal on a platelet unit is broken.
Red cells are stored at 1-6 degrees Celsius.
Frozen plasma and cryoprecipitated AHF are stored at

Question 66

White blood cell casts are MOST likely to indicate disease of the:

Answer 66

Kidney
(White blood cell casts are found most often in pyelonephritis cases involving the kidney. However, they may also be present in glomerulonephritis, interstitial nephritis, and lupus nephritis)

Question 67

The A1 subgroup represents approximately what percentage of group A individuals?

Answer 67

75-80%
(The A1 phenotype exists in about 80% of all group A individuals. The A2 phenotype constitutes about 20% of group A individuals. All the other subgroups consist of less than 1% of all group A individuals)