MLT ASCP Practice Test Questions with Answers and
Detailed Rationales | Complete Board Exam Study Guide for
Medical Laboratory Technologists
Q1. Glucose Dilution Calculation
Question: After experiencing extreme fatigue and polyuria, a patient's basic
metabolic panel is analyzed in the laboratory. The result of the glucose is too high
for the instrument to read. The laboratorian performs a dilution using 0.25 mL of
patient sample to 750 µL of diluent. The result now reads 325 mg/dL. How
should the technologist report this patient's glucose result?
Options:
A. 325 mg/dL
B. 1300 mg/dL ✅
C. 975 mg/dL
D. 1625 mg/dL
Rationale:
Total volume = 0.25 mL + 0.75 mL = 1 mL → dilution factor =
total/portion of sample = .25 = 4.
Measured glucose = 325 mg/dL. Multiply by dilution factor: 325 × 4 =
1300 mg/dL.
Q2. Christensen’s Urea Agar Slant Reaction
Question: The urease reaction seen in the Christensen's urea agar slant on the far
right indicates:
Options:
A. Weak activity ✅
B. Strong activity
,C. Slant only inoculated
D. Use of outdated medium
Rationale:
Pink color only in the slant = weak urease activity.
Strong urease activity turns both slant and butt pink.
Partial reaction may indicate early growth or weak producer.
Q3. First Step of PCR
Question: What is the first step of the PCR reaction?
Options:
A. Hybridization
B. Extension
C. Annealing
D. Denaturation ✅
Rationale:
PCR steps:
1. Denaturation: Heat separates double-stranded DNA.
2. Annealing/Hybridization: Primers bind to single strands.
3. Extension: DNA polymerase synthesizes complementary strand.
Q4. Isotonic Sodium Chloride
Question: The concentration of sodium chloride in an isotonic solution is:
Options:
A. 8.5%
B. 0.85% ✅
C. 0.08%
D. 1 M
Rationale:
, Normal saline (0.85% NaCl) matches osmotic pressure of blood → isotonic.
Q5. Lab Results in Acute DIC
Question: Which laboratory results would be seen in acute Disseminated
Intravascular Coagulation (DIC)?
Options:
A. Prolonged PT, elevated platelets, decreased FDP
B. Normal PT, decreased fibrinogen, decreased platelets, decreased FDP
C. Prolonged PT, decreased fibrinogen, decreased platelets, increased FDP ✅
D. Normal PT, decreased platelets, decreased FDP
Rationale:
DIC → widespread clot formation → consumption of clotting factors and
platelets → prolonged PT, decreased fibrinogen and platelets.
Clots are broken down → elevated fibrin degradation products (FDP).
Q6. Routine Sperm Count Dilution
Question: A dilution commonly used for a routine sperm count is:
Options:
A. 1:2
B. 1:20 ✅
C. 1:200
D. 1:400
Rationale:
Standard protocol uses 1:20 dilution to count sperm accurately in
hemocytometer.
Q7. Prozone Effect
, Question: The prozone effect (when performing a screening titer) is most likely
to result in:
Options:
A. False positive
B. False negative ✅
C. No reaction at all
D. Mixed field reaction
Rationale:
Prozone effect = antibody excess → inhibits visible agglutination → false
negative.
Diluting sample removes prozone → reaction becomes positive.
Q8. Nocardia Identification
Question: An agar quadrant plate containing casein (A), tyrosine (B), nitrate (C),
and xanthine (D) shows no hydrolysis of substrates, nitrate reduced. Likely
organism:
Options:
A. Nocardia asteroides ✅
B. Nocardia brasiliensis
C. Streptomyces griseus
D. Actinomadura madurae
Rationale:
N. asteroides → does not hydrolyze casein, tyrosine, xanthine, reduces
nitrate.
Other species hydrolyze some or all substrates.
Q9. Falsely Elevated Hemoglobin on Electronic Counter
Question: On an electronic cell counter, hemoglobin may be falsely elevated due
to:
Detailed Rationales | Complete Board Exam Study Guide for
Medical Laboratory Technologists
Q1. Glucose Dilution Calculation
Question: After experiencing extreme fatigue and polyuria, a patient's basic
metabolic panel is analyzed in the laboratory. The result of the glucose is too high
for the instrument to read. The laboratorian performs a dilution using 0.25 mL of
patient sample to 750 µL of diluent. The result now reads 325 mg/dL. How
should the technologist report this patient's glucose result?
Options:
A. 325 mg/dL
B. 1300 mg/dL ✅
C. 975 mg/dL
D. 1625 mg/dL
Rationale:
Total volume = 0.25 mL + 0.75 mL = 1 mL → dilution factor =
total/portion of sample = .25 = 4.
Measured glucose = 325 mg/dL. Multiply by dilution factor: 325 × 4 =
1300 mg/dL.
Q2. Christensen’s Urea Agar Slant Reaction
Question: The urease reaction seen in the Christensen's urea agar slant on the far
right indicates:
Options:
A. Weak activity ✅
B. Strong activity
,C. Slant only inoculated
D. Use of outdated medium
Rationale:
Pink color only in the slant = weak urease activity.
Strong urease activity turns both slant and butt pink.
Partial reaction may indicate early growth or weak producer.
Q3. First Step of PCR
Question: What is the first step of the PCR reaction?
Options:
A. Hybridization
B. Extension
C. Annealing
D. Denaturation ✅
Rationale:
PCR steps:
1. Denaturation: Heat separates double-stranded DNA.
2. Annealing/Hybridization: Primers bind to single strands.
3. Extension: DNA polymerase synthesizes complementary strand.
Q4. Isotonic Sodium Chloride
Question: The concentration of sodium chloride in an isotonic solution is:
Options:
A. 8.5%
B. 0.85% ✅
C. 0.08%
D. 1 M
Rationale:
, Normal saline (0.85% NaCl) matches osmotic pressure of blood → isotonic.
Q5. Lab Results in Acute DIC
Question: Which laboratory results would be seen in acute Disseminated
Intravascular Coagulation (DIC)?
Options:
A. Prolonged PT, elevated platelets, decreased FDP
B. Normal PT, decreased fibrinogen, decreased platelets, decreased FDP
C. Prolonged PT, decreased fibrinogen, decreased platelets, increased FDP ✅
D. Normal PT, decreased platelets, decreased FDP
Rationale:
DIC → widespread clot formation → consumption of clotting factors and
platelets → prolonged PT, decreased fibrinogen and platelets.
Clots are broken down → elevated fibrin degradation products (FDP).
Q6. Routine Sperm Count Dilution
Question: A dilution commonly used for a routine sperm count is:
Options:
A. 1:2
B. 1:20 ✅
C. 1:200
D. 1:400
Rationale:
Standard protocol uses 1:20 dilution to count sperm accurately in
hemocytometer.
Q7. Prozone Effect
, Question: The prozone effect (when performing a screening titer) is most likely
to result in:
Options:
A. False positive
B. False negative ✅
C. No reaction at all
D. Mixed field reaction
Rationale:
Prozone effect = antibody excess → inhibits visible agglutination → false
negative.
Diluting sample removes prozone → reaction becomes positive.
Q8. Nocardia Identification
Question: An agar quadrant plate containing casein (A), tyrosine (B), nitrate (C),
and xanthine (D) shows no hydrolysis of substrates, nitrate reduced. Likely
organism:
Options:
A. Nocardia asteroides ✅
B. Nocardia brasiliensis
C. Streptomyces griseus
D. Actinomadura madurae
Rationale:
N. asteroides → does not hydrolyze casein, tyrosine, xanthine, reduces
nitrate.
Other species hydrolyze some or all substrates.
Q9. Falsely Elevated Hemoglobin on Electronic Counter
Question: On an electronic cell counter, hemoglobin may be falsely elevated due
to:
