(Self-Assessment) Examination Flashcards
1
Q
- In absorption spectrophotometry:
A. Absorbance is directly proportional to
transmittance
B. Percent transmittance is directly
proportional to concentration
C. Percent transmittance is directly
proportional to the light path length
D. Absorbance is directly proportional to concentration
A
D. Absorbance is directly proportional to concentration
2
Q
- Which type of filter is best for measuring
stray light?
A. Wratten
B. Didymium
C. Sharp cutoff
D. Neutral density
A
C. Sharp cutoff
3
Q
- A plasma sample is hemolyzed and turbid.
What is required to perform a sample blank
in order to correct the measurement for the
intrinsic absorbance of the sample when
performing a spectrophotometric assay?
A. Substitute deionized water for the sample
B. Dilute the sample 1:2 with a standard of
known concentration
C. Substitute saline for the reagent
D. Use a larger volume of the sample
A
C. Substitute saline for the reagent
4
Q
- The response of a sodium electrode to a
10-fold increase in sodium concentration
should be:
A. A 10-fold drop in potential
B. An increase in potential of approximately
60 mV
C. An increase in potential of approximately
10 mV
D. A decrease in potential of approximately
10 mV
A
B. An increase in potential of approximately
60 mV
5
Q
- In gas chromatography, the elution order of
volatiles is usually based upon the:
A. Boiling point
B. Molecular size
C. Carbon content
D. Polarity
A
A. Boiling point
6
Q
- A patient’s blood gas results are as
follows:
pH = 7.26
dCO2 = 2.0 mmol/L
HCO3– = 29 mmol/L
These results would be classified as:
A. Metabolic acidosis
B. Metabolic alkalosis
C. Respiratory acidosis
D. Respiratory alkalosis
A
C. Respiratory acidosis
7
Q
- Which condition results in metabolic
acidosis with severe hypokalemia and
chronic alkaline urine?
A. Diabetic ketoacidosis
B. Phenformin-induced acidosis
C. Renal tubular acidosis
D. Acidosis caused by starvation
A
C. Renal tubular acidosis
8
Q
- Which of the following conditions will cause
an increased anion gap?
A. Diarrhea
B. Hypoaldosteronism
C. Hyperkalemia
D. Renal failure
A
D. Renal failure
9
Q
- Which of the following tests is consistently
abnormal in osteoporosis?
A. High urinary calcium
B. High serum Pi
C. Low serum calcium
D. High urine or serum N-telopeptide of
type I collagen
A
D. High urine or serum N-telopeptide of
type I collagen
10
Q
- SITUATION: An EDTA sample for TnI
assay gives a result of 0.04 ng/mL (reference
range 0–0.03 ng/mL). The test is repeated
3 hours later on a new specimen and the
result is 0.06 ng/mL. A third sample collected
6 hours later gives a result of 0.07 ng/mL.
The EKG showed no evidence of ST segment
elevation (STEMI). What is the most likely
explanation?
A. A false-positive result occurred due to
matrix interference
B. Heparin should have been used
instead of EDTA, which causes false
positives
C. The patient has suffered cardiac injury
D. The patient has had an ischemic episode
without cardiac injury
A
C. The patient has suffered cardiac injury
11
Q
- Which electrolyte level best correlates with
plasma osmolality?
A. Sodium
B. Chloride
C. Bicarbonate
D. Calcium
A
A. Sodium
12
Q
- According to American Diabetes Association
criteria, which result is consistent with a
diagnosis of impaired fasting glucose?
A. 99 mg/dL
B. 117 mg/dL
C. 126 mg/dL
D. 135 mg/dL
A
B. 117 mg/dL
13
Q
- Which enzyme is responsible for the
conjugation of bilirubin?
A. β-Glucuronidase
B. UDP-glucuronyl transferase
C. Bilirubin oxidase
D. Biliverdin reductase
A
B. UDP-glucuronyl transferase
14
Q
- Which of the following conditions is cause
for rejecting an analytical run?
A. Two consecutive controls greater than
2 s above or below the mean
B. Three consecutive controls greater than
1 s above the mean
C. Four controls steadily increasing in value
but less than ±1 s from the mean
D. One control above +1 s and the other
below -1 s from the mean
A
A. Two consecutive controls greater than 2 s above or below the mean
15
Q
- In the ultraviolet enzymatic method for
BUN, the urease reaction is coupled to a
second enzymatic reaction using:
A. Aspartate aminotransferase (AST)
B. Glutamate dehydrogenase
C. Glutamine synthetase
D. Alanine aminotransferase (ALT)
A
B. Glutamate dehydrogenase
16
Q
- In the Oliver–Rosalki method, the reverse
reaction is used to measure creatine kinase
activity. The enzyme(s) used in the coupling
reactions are:
A. Hexokinase and glucose-6-phosphate
dehydrogenase
B. Pyruvate kinase and lactate dehydrogenase
C. Luciferase
D. Adenylate kinase
A
A. Hexokinase and glucose-6-phosphate
dehydrogenase
17
Q
- In familial β dyslipoproteinemia (formerly
Type III hyperlipoproteinemia), which
lipoprotein accumulates?
A. Chylomicrons
B. VLDL
C. IDL
D. VLDL
A
C. IDL
18
Q
- A manual white blood cell (WBC) count was
performed. A total of 36 cells were counted
in all 9-mm2 squares of a Neubauer-ruled
hemacytometer. A 1:10 dilution was used.
What is the WBC count?
A. 0.4 × 109/L
B. 2.5 × 109/L
C. 4.0 × 109/L
D. 8.0 × 109/L
A
A. 0.4 × 109/L
19
Q
- Which ratio of anticoagulant to blood is
correct for coagulation procedures?
A. 1:4
B. 1:5
C. 1:9
D. 1:10
A
C. 1:9
20
Q
- Given the following values, which set of red
blood cell indices suggests spherocytosis?
A. MCV MCH MCHC
76 μm3 19.9 pg 28.5%
B. MCV MCH MCHC
90 μm3 30.5 pg 32.5%
C. MCV MCH MCHC
80 μm3 36.5 pg 39.0%
D. MCV MCH MCHC
81 μm3 29.0 pg 34.8%
A
C. MCV MCH MCHC
80 μm3 36.5 pg 39.0%
21
Q
- Congenital dyserythropoietic anemias
(CDAs) are characterized by:
A. Bizarre multinucleated erythroblasts
B. Cytogenetic disorders
C. Megaloblastic erythropoiesis
D. An elevated M:E ratio
A
A. Bizarre multinucleated erythroblasts
22
Q
- Which anemia has red cell morphology
similar to that seen in iron deficiency anemia?
A. Sickle cell anemia
B. Thalassemia syndrome
C. Pernicious anemia
D. Hereditary spherocytosis
A
B. Thalassemia syndrome
23
Q
- A 50-year-old patient is suffering from pernicious anemia. Which of the following laboratory data are most likely for this patient?
A
D.
24
Q
- Neutrophil phagocytosis and particle
ingestion are associated with an increase in
oxygen utilization referred to as respiratory
burst. What are the two most important
products of this biochemical reaction?
A. Hydrogen peroxide and superoxide
anion
B. Lactoferrin and NADPH oxidase
C. Cytochrome b and collagenase
D. Alkaline phosphatase and ascorbic acid
A
A. Hydrogen peroxide and superoxide
anion
25
Q
- Disseminated intravascular coagulation
(DIC) is most often associated with which
of the following types of acute leukemia?
A. Acute myeloid leukemia without
maturation
B. Acute promyelocytic leukemia
C. Acute myelomonocytic leukemia
D. Acute monocytic leukemia
A
B. Acute promyelocytic leukemia
26
Q
- What would be the most likely designation
by the WHO for the FAB AML M2 by the
French–American–British classification?
A. AML with t(15;17)
B. AML with mixed lineage
C. AML with t(8;21)
D. AML with inv(16)
A
C. AML with t(8;21)
27
Q
- A patient’s peripheral blood smear and bone
marrow both show 70% blasts. These cells
are negative for Sudan Black B stain. Given
these data, which of the following is the most
likely diagnosis?
A. Acute myeloid leukemia
B. Chronic lymphocytic leukemia
C. Acute promyelocytic leukemia
D. Acute lymphocytic leukemia
A
D. Acute lymphocytic leukemia
28
Q
- Which of the following is (are) commonly
found in CML?
A. Many teardrop-shaped cells
B. Intense LAP staining
C. A decrease in granulocytes
D. An increase in basophils
A
D. An increase in basophils
29
Q
- SITUATION: A peripheral smear shows
75% blasts. These stain positive for both
Sudan Black B (SBB) and peroxidase. Given
these values, which of the following disorders
is most likely?
A. Acute myelocytic leukemia (AML)
B. Chronic myelogenous leukemia (CML)
C. Acute undifferentiated leukemia (AUL)
D. Acute lymphocytic leukemia (ALL)
A
A. Acute myelocytic leukemia (AML)
30
Q
- Which of the following is often associated
with CML but not with AML?
A. Infections
B. WBCs greater than 20.0 × 109/L
C. Hemorrhage
D. Splenomegaly
A
D. Splenomegaly
31
Q
- Review the following CBC results:
Which of the following additional laboratory
tests would yield informative diagnostic
information for this patient?
A. Osmotic fragility
B. Hgb electrophoresis
C. Sugar water test
D. Bone marrow examination
A
B. Hgb electrophoresis
32
Q
- Which of the following platelet aggregating
agents demonstrates a monophasic
aggregation curve when used in optimal
concentration?
A. Thrombin
B. Collagen
C. Adenosine diphosphate (ADP)
D. Epinephrine
A
B. Collagen
33
Q
- Which factor deficiency is associated with a
prolonged PT and APTT?
A. X
B. VIII
C. IX
D. XI
A
A. X
34
Q
- Which of the following is an appropriate
screening test for the diagnosis of lupus
anticoagulant?
A. Thrombin time test
B. Diluted Russell’s viper venom test
(DRVVT)
C. D-dimer test
D. FDP test
A
B. Diluted Russell’s viper venom test
(DRVVT)
35
Q
- Factor V Leiden promotes thrombosis by
preventing:
A. Deactivation of factor Va
B. Activation of factor V
C. Activation of protein C
D. Activation of protein S
A
A. Deactivation of factor Va
36
Q
- Which cluster of differentiation (CD) marker
appears during the first stage of T-cell
development and remains present as an
identifying marker for T cells?
A. CD1
B. CD2
C. CD3
D. CD4 or CD8
A
B. CD2
37
Q
- Which MHC class of molecule is necessary
for antigen recognition by CD4-positive
T cells?
A. Class I
B. Class II
C. Class III
D. No MHC molecule is necessary for antigen
recognition
A
B. Class II
38
Q
- What has happened in a titer, if tube
Nos. 5–7 show a stronger reaction than tube
Nos.1–4?
A. Prozone reaction
B. Postzone reaction
C. Equivalence reaction
D. Poor technique
A
A. Prozone reaction
39
Q
- What is the titer in tube No. 8 if tube No. 1
is undiluted and dilutions are doubled?
A. 64
B. 128
C. 256
D. 512
A
B. 128
40
Q
- Which is most likely a positive Western blot
result for infection with HIV?
A. Band at p24
B. Band at gp60
C. Bands at p24 and p31
D. Bands at p24 and gp120
A
D. Bands at p24 and gp120
41
Q
- Serological tests for which disease may give a
false-positive result if the patient has Lyme
disease?
A. AIDS
B. Syphilis
C. Cold agglutinins
D. Hepatitis C
A
B. Syphilis
42
Q
- Which of the following methods used for
HIV identification is considered a signal
amplification technique?
A. Branched-chain DNA analysis
B. DNA PCR
C. Reverse transcriptase PCR
D. Nucleic acid sequence–based assay
(NASBA)
A
A. Branched-chain DNA analysis
43
Q
- What antibodies are represented by the
nucleolar pattern in the immunofluorescence
test for antinuclear antibodies?
A. Antihistone antibodies
B. Anti-dsDNA antibodies
C. Anti-ENA (anti-Sm and anti-RNP)
antibodies
D. Anti-RNA antibodies
A
D. Anti-RNA antibodies
44
Q
- Which of the following is used in rapid slide
tests for detection of rheumatoid factors?
A. Whole IgM molecules
B. Fc portion of the IgG molecule
C. Fab portion of the IgG molecule
D. Fc portion of the IgM molecule
A
B. Fc portion of the IgG molecule
45
Q
- A patient deficient in the C3 complement
component would be expected to mount a
normal:
A. Type I and IV hypersensitivity response
B. Type II and IV hypersensitivity response
C. Type I and III hypersensitivity response
D. Type II and III hypersensitivity response
A
A. Type I and IV hypersensitivity response
46
Q
- Which disease may be expected to show an
IgM spike on an electrophoretic pattern?
A. Hypogammaglobulinemia
B. Multicystic kidney disease
C. Waldenström’s macroglobulinemia
D. Wiskott–Aldrich syndrome
A
C. Waldenström’s macroglobulinemia
47
Q
- Interpret the following description of an
immunofixation electrophoresis assay of
urine. Dense wide bands in both the κ
and λ lanes. No bands present in the heavy
chain lanes.
A. Normal
B. Light chain disease
C. Increased polyclonal Fab fragments
D. Multiple myeloma
A
C. Increased polyclonal Fab fragments
48
Q
- Which of the following serial dilutions
contains an incorrect factor?
A. 1:4, 1:8, 1:16
B. 1:1, 1:2, 1:4
C. 1:5, 1:15, 1:45
D. 1:2, 1:6, 1:12
A
D. 1:2, 1:6, 1:12
49
Q
- A patient with joint swelling and pain
tested negative for serum RF by both latex
agglutination and ELISA methods. What
other test would help establish a diagnosis
of RA in this patient?
A. Anti CCP antibody
B. ANA testing
C. Flow cytometry
D. Complement levels
A
A. Anti CCP antibody
50
Q
- Which hepatitis B marker is the best
indicator of early acute infection?
A. HBsAg
B. HBeAg
C. Anti-HBc
D. Anti-HBs
A
A. HBsAg
51
Q
- Which genotype(s) will give rise to the
Bombay phenotype?
A. HH only
B. HH and Hh
C. Hh and hh
D. hh only
A
D. hh only
52
Q
- A patient’s red cells forward as group O,
serum agglutinates B cells (4+) only. Your
next step would be:
A. Extend reverse typing for 15 minutes
B. Perform an antibody screen including a
room temperature incubation
C. Incubate washed red cells with anti-A1 and
Anti-A,B for 30 minutes at room temperature
D. Test patient’s red cells with Dolichos biflorus
A
C. Incubate washed red cells with anti-A1 and Anti-A,B for 30 minutes at room temperature
53
Q
- A physician orders 2 units of leukocyte
reduced red blood cells. The patient is a
55-year-old male with anemia. He types as
an AB negative, and his antibody screen is
negative. There is only 1 unit of AB negative
in inventory. What is the next blood type
that should be given?
A. AB positive (patient is male)
B. A negative
C. B negative
D. O negative
A
B. A negative
54
Q
- What type of blood should be given an
individual who has an anti-Leb that reacts
1+ at the IAT phase?
A. Blood that is negative for the Leb antigen
B. Blood that is negative for both the Lea and
Leb antigens
C. Blood that is positive for the Leb antigen
D. Lewis antibodies are not clinically significant,
so any type of blood may be given
A
A. Blood that is negative for the Leb antigen
55
Q
- Which antibody is frequently seen in patients
with warm autoimmune hemolytic anemia?
A. Anti-Jka
B. Anti-e
C. Anti-K
D. Anti-Fyb
A
B. Anti-e
56
Q
- Which procedure would help to distinguish
between an anti-e and anti-Fya in an
antibody mixture?
A. Lower pH of test serum
B. Run an enzyme panel
C. Use a thiol reagent
D. Run a LISS panel
A
B. Run an enzyme panel
57
Q
- A donor was found to contain anti-K using
pilot tubes from the collection procedure.
How would this affect the compatibility test?
A. The AHG major crossmatch would be
positive
B. The IS (immediate spin) major crossmatch
would be positive
C. The recipient’s antibody screen would be
positive for anti-K
D. Compatibility testing would not be affected
A
D. Compatibility testing would not be affected
58
Q
- Six units are crossmatched. Five units are
compatible, one unit is incompatible, and the
recipient’s antibody screen is negative.
Identify the problem:
A. Patient may have an alloantibody to a
high-frequency antigen
B. Patient may have an abnormal protein
C. Donor unit may have a positive DAT
D. Donor may have a high-frequency antigen
A
C. Donor unit may have a positive DAT
59
Q
- How long must a recipient sample be kept in
the blood bank following compatibility
testing?
A. 3 days
B. 5 days
C. 7 days
D. 10 days
A
C. 7 days
60
Q
- A patient had a transfusion reaction to
packed red blood cells. The medical
laboratory scientist began the laboratory
investigation of the transfusion reaction by
assembling pre- and post-transfusion
specimens and all paperwork and computer
printouts. What should he do next?
A. Perform a DAT on the post-transfusion
sample
B. Check for a clerical error(s)
C. Repeat ABO and Rh typing of patient and
donor unit
D. Perform an antibody screen on the
post-transfusion sample
A
B. Check for a clerical error(s)
61
Q
- What may be found in the serum of a
person who is exhibiting signs of TRALI
(transfusion-related acute lung injury)?
A. Red blood cell alloantibody
B. IgA antibody
C. Antileukocyte antibody
D. Allergen
A
C. Antileukocyte antibody
62
Q
- Which of the following is acceptable
according to AABB standards?
A. Rejuvenated RBCs may be made within
3 days of outdate and transfused or frozen
within 24 hours of rejuvenation
B. Frozen RBCs must be prepared within
30 minutes of collection and may be used
within 10 years
C. Irradiated RBCs must be treated within
8 hours of collection and transfused within
6 hours
D. Leukocyte-reduced RBCs must be prepared
within 6 hours of collection and transfused
within 6 hours of preparation
A
A. Rejuvenated RBCs may be made within
3 days of outdate and transfused or frozen
within 24 hours of rejuvenation
63
Q
- A unit of packed RBCs is split using the
open system. One of the half units is
used. What may be done with the second
half unit?
A. Must be issued within 24 hours
B. Must be issued within 48 hours
C. Must be irradiated
D. Retains the original expiration date
A
A. Must be issued within 24 hours
64
Q
- What percentage of red cells must be
retained in leukocyte-reduced red cells?
A. 75%
B. 80%
C. 85%
D. 100%
A
C. 85%
65
Q
- Which of the following individuals is
acceptable as a blood donor?
A. A 29-year-old man who received the
hepatitis B vaccine last week
B. A 21-year-old woman who has had her
nose pierced last week
C. A 30-year-old man who lived in Zambia
for 3 years and returned last month
D. A 54-year-old man who tested positive for
hepatitis C last year, but has no active
symptoms of disease
A
A. A 29-year-old man who received the
hepatitis B vaccine last week
66
Q
- Which of the following vaccinations carries
no deferral period?
A. Rubella
B. Varicella zoster
C. Recombinant HPV
D. Smallpox
A
C. Recombinant HPV
67
Q
- Can an autologous donor donate blood on
Monday, if he is having surgery on Friday?
A. Yes, he or she can donate up to 72 hours
before surgery
B. No, he or she cannot donate with 7 days of
surgery
C. Yes, he or she can donate, but only a half
a unit
D. No, he or she cannot donate within 5 days
of surgery
A
A. Yes, he or she can donate up to 72 hours
before surgery
68
Q
- A fetal screen yielded negative results on a
mother who is O negative and infant who is
O positive. What course of action should be
taken?
A. Perform a Kleihauer–Betke test
B. Issue one full dose of RhIg
C. Perform a DAT on the infant
D. Perform an antibody screen on the mother
A
B. Issue one full dose of RhIg
69
Q
- Should an A-negative woman who has just
had a miscarriage receive RhIg?
A. Yes, but only if she does not have evidence
of active Anti-D
B. No, the type of the baby is unknown
C. Yes, but only a minidose regardless of
trimester
D. No, RhIg is given for term pregnancies only
A
A. Yes, but only if she does not have evidence
of active Anti-D
70
Q
- John comes in to donate a unit of whole
blood at the collection center of the
community blood supplier. The EIA screen is
reactive for anti-HIV-1/2. The test is
repeated in duplicate and is nonreactive.
John is:
A. Cleared for donation
B. Deferred for six months
C. Status is dependent on confirmatory test
D. Deferred for 12 months
A
A. Cleared for donation
71
Q
- Urine with an SG consistently between 1.002 and 1.003 indicates:
A. Acute glomerulonephritis
B. Renal tubular failure
C. Diabetes insipidus
D. Addison’s disease
A
C. Diabetes insipidus
72
Q
- What is the principle of the colorimetric
reagent strip determination of SG in urine?
A. Ionic strength alters the pKa of a
polyelectrolyte
B. Sodium and other cations are chelated by a
ligand that changes color
C. Anions displace a pH indicator from a
mordant, making it water soluble
D. Ionized solutes catalyze oxidation of an azo dye
A
A. Ionic strength alters the pKa of a
polyelectrolyte
73
Q
- Which of the following is most likely to cause a false-positive dry reagent strip test for protein?
A. Urine of high SG
B. Highly buffered alkaline urine
C. Bence–Jones proteinuria
D. Salicylates
A
B. Highly buffered alkaline urine
74
Q
- A discrepancy between the urine SG
determined by measuring refractive index
and urine osmolality would be most likely to
occur:
A. After catheterization of the urinary tract
B. In diabetes mellitus
C. After an intravenous pyelogram (IVP)
D. In uremia
A
C. After an intravenous pyelogram (IVP)
75
Q
- In what condition may urinary ketone tests
underestimate ketosis?
A. Acidosis
B. Hemolytic anemia
C. Renal failure
D. Excessive use of vitamin C
A
A. Acidosis
76
Q
- Which of the following results are
discrepant?
A. Small blood but negative protein
B. Moderate blood but no RBCs in
microscopic exam
C. Negative blood but 6–10 RBCs/HPF
D. Negative blood, positive protein
A
C. Negative blood but 6–10 RBCs/HPF
77
Q
- Renal tubular epithelial cells are shed into
the urine in largest numbers in which
condition?
A. Malignant renal disease
B. Acute glomerulonephritis
C. Nephrotic syndrome
D. Cytomegalovirus (CMV) infection of the kidney
A
D. Cytomegalovirus (CMV) infection of the kidney
78
Q
- The diagnosis of multiple sclerosis is often
based upon which finding?
A. The presence of elevated protein and low
glucose
B. A decreased IgG index
C. The presence of oligoclonal bands by
electrophoresis
D. An increased level of CSF β microglobulin
A
C. The presence of oligoclonal bands by
electrophoresis
79
Q
- Which of the following laboratory results is
characteristic of a transudative fluid?
A. SG = 1.018
B. Total protein = 3.2 g/dL
C. LD fluid/serum ratio = 0.25
D. Total protein fluid/serum ratio = 0.65
A
C. LD fluid/serum ratio = 0.25
80
Q
- Which of the following conditions is
commonly associated with an exudative
effusion?
A. Congestive heart failure
B. Malignancy
C. Nephrotic syndrome
D. Cirrhosis
A
B. Malignancy
81
Q
- Which of the following sample collection and
processing conditions will lead to inaccurate
seminal fluid analysis results?
A. Sample stored at room temperature for
1 hour before testing
B. Sample collected following coitus
C. Sample collected without an anticoagulant
D. Sample collected without use of a condom
A
B. Sample collected following coitus
82
Q
- A blood-tainted pleural fluid is submitted for
culture. Which test result would be most
conclusive in classifying the fluid as an
exudate?
A. LD fluid/serum = 0.65
B. Total protein = 3.2 g/dL
C. RBC count = 10,000/μL
D. WBC count = 1,500/uL
A
A. LD fluid/serum = 0.65
83
Q
- What is the purpose of adding
0.025%–0.050% sodium polyanethol
sulfonate (SPS) to nutrient broth media
for the collection of blood cultures?
A. It inhibits phagocytosis and complement
B. It promotes formation of a blood clot
C. It enhances growth of anaerobes
D. It functions as a preservative
A
A. It inhibits phagocytosis and complement
84
Q
- Xylose lysine deoxycholate (XLD) agar is a
highly selective medium used for the recovery
of which bacteria?
A. Staphylococcus spp. from normal flora
B. Yersinia spp. that do not grow on
Hektoen agar
C. Enterobacteriaceae from gastrointestinal
specimens
D. Streptococcus spp. from stool cultures
A
C. Enterobacteriaceae from gastrointestinal
specimens
85
Q
- Which genera are positive for phenylalanine
deaminase?
A. Enterobacter, Escherichia, and Salmonella
B. Morganella, Providencia, and Proteus
C. Klebsiella and Enterobacter
D. Proteus, Escherichia, and Shigella
A
B. Morganella, Providencia, and Proteus
86
Q
- Four blood cultures were taken over
a 24-hour period from a 20-year-old
woman with severe diarrhea. The
cultures grew motile (room temperature),
gram-negative rods. A urine specimen
obtained by catheterization also showed
gram-negative rods, 100,000 col/mL. Given the following results, which is the most likely organism?
TSI = A/A gas
Indole = +
VP = Neg
MR = +
H2S = Neg
Citrate = Neg
Urease = Neg
Lysine decarboxylase = +
Phenylalanine deaminase = Neg
A. Proteus vulgaris
B. Salmonella typhi
C. Yersinia enterocolitica
D. E. coli
A
D. E. coli
87
Q
- A bloody stool from a 26-year-old woman
with 3 days of severe diarrhea showed the
following results at 48 hours after being
plated on the following media:
MacConkey agar: little normal flora with
many nonlactose-fermenting colonies
Hektoen enteric agar: many blue-green
colonies
Campylobacter blood agar and C. difficile agar:
no growth
Clear colonies (from MacConkey agar) tested
negative for oxidase, indole, urease, motility,
and H2S
The most likely identification is:
A. Shigella spp.
B. Salmonella spp.
C. Proteus spp.
D. E. coli
A
A. Shigella spp.
88
Q
- The following results were obtained from a pure culture of gram-negative rods recovered from the pulmonary secretions of a 10-year-old cystic fibrosis patient with pneumonia:
Oxidase = +
Motility = +
Glucose OF (open) = +
Gelatin hydrolysis = +
Pigment = Red (nonfluorescent)
Growth at 42°C = +
Flagella = + (polar monotrichous)
Arginine dihydrolase = +
Which is the most likely organism?
A. Burkholderia pseudomallei
B. Pseudomonas stutzeri
C. Burkholderia cepacia
D. Pseudomonas aeruginosa
A
D. Pseudomonas aeruginosa
89
Q
- A yellow pigment–producing organism that
is oxidase positive, nonmotile, and does not
grow on MacConkey agar is:
A. Acinetobacter baumannii
B. Acinetobacter lwoffii
C. Burkholderia cepacia
D. Chryseobacterium meningosepticum
A
D. Chryseobacterium meningosepticum
90
Q
- Which of the following tests should be done
first in order to differentiate Aeromonas spp.
from the Enterobacteriaceae?
A. Urease
B. OF glucose
C. Oxidase
D. Catalase
A
C. Oxidase
91
Q
- The following results were observed by using a tube coagulase test:
Coagulase at 4 hours = +
Coagulase at 18 hours = Neg
Novobiocin = Sensitive
Hemolysis on blood agar = β (16-mm zone)
Mannitol salt plate = +
DNase = + (acid production)
What is the most probable identification?
A. Staphylococcus saprophyticus
B. Staphylococcus epidermidis
C. Staphylococcus aureus
D. Staphylococcus hominis
A
C. Staphylococcus aureus
92
Q
- Two blood cultures on a newborn grew β-hemolytic streptococci with the following reactions:
CAMP test = +
Hippurate hydrolysis = +
Bile solubility = Neg
6.5% salt = +
Bacitracin = Resistant
Bile esculin = Neg
PYR = Neg
Trimethoprim–
sulfamethoxazole =
Resistant
Which is the most likely identification?
A. Group A streptococci
B. Group B streptococci
C. Group D streptococci
D. Nongroup A, nongroup B, nongroup
D streptococci
A
B. Group B streptococci
93
Q
- A gram-positive spore-forming bacillus
growing on sheep-blood agar anaerobically
produces a double zone of β-hemolysis and
is positive for lecithinase. What is the
presumptive identification?
A. Bacteroides ureolyticus
B. Bacteroides fragilis
C. Clostridium perfringens
D. Clostridium difficile
A
C. Clostridium perfringens
94
Q
- A small, gram-negative coccobacillus
recovered from the CSF of a 2-year-old
child gave the following results:
Indole = +
Glucose = + (acid)
X requirement = +
V requirement = +
Urease = +
Lactose = Neg
Sucrose = Neg
Hemolysis = Neg
Which is the most likely identification?
A. Haemophilus parainfluenzae
B. Haemophilus influenzae
C. Haemophilus ducreyi
D. Haemophilus aphrophilus
A
B. Haemophilus influenzae
95
Q
- Growth inhibition by thiophene-2-carboxylic hydrazide (T2H) is used to differentiate M. tuberculosis from which other Mycobacterium specie?
A. M. bovis
B. M. avium–intracellulare complex
C. M. kansasii
D. M. marinum
A
A. M. bovis
96
Q
- Arthrospore (arthroconidia) production
is used to differentiate which two yeast
isolates?
A. Candida albicans and Candida
stellatoidea
B. Trichosporon spp. and Cryptococcus spp.
C. Candida albicans and Candida
tropicalis
D. Saccharomyces cerevisiae and Candida
(Torulopsis) glabrata
A
B. Trichosporon spp. and Cryptococcus spp.
97
Q
- A thermally dimorphic fungus shows a filamentous mold form with tuberculate macroconidia at room temperature, and a
yeast form above 35°C.
Which organism
best fits this description?
A. Histoplasma capsulatum
B. Paracoccidioides brasiliensis
C. Candida albicans
D. Coccidioides immitis
A
A. Histoplasma capsulatum
98
Q
- An Entamoeba histolytica trophozoite has the following characteristics:
A. Central karyosome in the nucleus, ingested
RBCs, and clear pseudopodia
B. Ingested RBCs, clear pseudopodia, and uneven chromatin on the nuclear membrane
C. Ingested RBCs, clear pseudopodia, and
large glycogen vacuoles in cytoplasm
D. Large, blotlike karyosome, ingested white blood cells (WBCs), and granular
pseudopods
A
A. Central karyosome in the nucleus, ingested RBCs, and clear pseudopodia
99
Q
- Cysts of Iodamoeba bütschlii typically have:
A. Chromatoidal bars with rounded ends
B. A heavily vacuolated cytoplasm
C. A large glycogen vacuole
D. Many ingested bacteria and yeast cells
A
C. A large glycogen vacuole
100
Q
- What gene must be amplified in PCR to differentiate methicillin-resistant
Staphylococcus aureus from methicillin resistant coagulase-negative
Staphylococcus?
A. orfX
B. mecA
C. VanA
D. iles-2
A
A. orfX
