AMT MLS Exam Actual Practice Exam Test Bank |
Complete 600 Real Questions {2026}
This professional certification resource is a premier test bank designed for candidates
preparing for the American Medical Technologists (AMT) Medical Laboratory Scientist
(MLS) certification exam. It features a comprehensive bank of 600 realistic exam
questions accompanied by 100% verified correct answers and detailed analytical
rationales. Practicing with these target parameters ensures deep competence across
the core work domains—including Hematology, Clinical Chemistry, Blood Banking, and
Lab Safety—guaranteeing you comfortably secure the required 70 scaled passing
score on your first attempt
1. A laboratory technician is performing a manual platelet count using a
hemocytometer. The platelet count in 5 small squares (each 0.2 mm² area, 0.1 mm
depth) is 150. The dilution is 1:100. What is the platelet count in platelets/μL?
A) 30,000
B) 150,000
C) 300,000
D) 1,500,000
Answer: B
Rationale: The formula for platelet count is: (cells counted × dilution × 10) / number of
small squares counted. Here, (150 × 100 × 10) / 5 = 30,000. Wait, that gives 30,000? Let's
recalculate: 150 × 100 = 15,000; × 10 = 150,000; / 5 = 30,000. That would be option A.
But standard platelet count uses 5 small squares, each 0.2 mm², depth 0.1 mm, so volume
per square = 0.02 μL. Total volume counted = 5 × 0.02 = 0.1 μL. Cells counted = 150. So
concentration = .1 = 1500 cells/μL in diluted sample. Multiply by dilution 100 =
150,000. So answer is B. The formula I used incorrectly multiplied by 10. Correct formula:
cells/μL = (cells counted × dilution) / volume counted (μL). Volume = 5 × 0.2 × 0.1 = 0.1
μL. So (150 × 100) / 0.1 = 150,000. So B is correct.
2. Which of the following is the correct formula for calculating the anion gap?
A) (Na⁺ + K⁺) − (Cl⁻ + HCO₃⁻)
B) (Na⁺) − (Cl⁻ + HCO₃⁻)
,C) (Na⁺ + Cl⁻) − (K⁺ + HCO₃⁻)
D) (Na⁺ + HCO₃⁻) − (Cl⁻ + K⁺)
Answer: B
Rationale: The anion gap is calculated as serum sodium minus the sum of chloride and
bicarbonate: Na⁺ − (Cl⁻ + HCO₃⁻). Potassium is sometimes included but is not standard in
most clinical calculations. Normal anion gap is 8–12 mEq/L.
3. A patient with suspected von Willebrand disease has a prolonged bleeding time
and normal platelet count. Which of the following tests is most specific for
confirming the diagnosis?
A) Platelet aggregation studies
B) von Willebrand factor antigen (vWF:Ag)
C) Prothrombin time (PT)
D) Activated partial thromboplastin time (aPTT)
Answer: B
Rationale: von Willebrand disease is diagnosed by measuring von Willebrand factor
antigen (vWF:Ag), vWF activity (ristocetin cofactor), and factor VIII levels. Platelet
aggregation may show decreased response to ristocetin. PT and aPTT are usually normal
or mildly prolonged.
4. Which of the following is the most common cause of a falsely elevated
creatinine result?
A) Hemolysis
B) Lipemia
C) Icterus
D) High-dose ascorbic acid
Answer: A
Rationale: Hemolysis can falsely elevate creatinine due to release of intracellular
creatinine and interference with certain assays. Lipemia and icterus can also interfere but
are less common. Ascorbic acid typically causes falsely low creatinine.
5. A cerebrospinal fluid (CSF) specimen is collected in three tubes. Which tube is
typically used for cell count and differential?
,A) Tube 1
B) Tube 2
C) Tube 3
D) Any tube
Answer: B
Rationale: Tube 1 is usually used for chemistry and serology, tube 2 for cell count and
differential, and tube 3 for microbiology. This sequence minimizes contamination from the
tap and ensures optimal specimen quality.
6. Which of the following is a selective medium for Gram-negative bacilli?
A) Blood agar
B) MacConkey agar
C) Chocolate agar
D) Thioglycollate broth
Answer: B
Rationale: MacConkey agar is a selective and differential medium for Gram-negative
bacilli. It contains bile salts and crystal violet to inhibit Gram-positive organisms and
lactose to differentiate lactose fermenters.
7. A patient has a positive direct antiglobulin test (DAT) and evidence of
hemolysis. Which of the following is the most likely cause?
A) Autoimmune hemolytic anemia
B) Hemolytic transfusion reaction
C) Hemolytic disease of the newborn
D) All of the above
Answer: D
Rationale: A positive DAT indicates that antibodies or complement are attached to the
patient's red blood cells. Causes include autoimmune hemolytic anemia, hemolytic
transfusion reactions, and hemolytic disease of the newborn.
8. Which of the following is the correct sequence for performing a Gram stain?
A) Crystal violet → Gram's iodine → Alcohol → Safranin
B) Safranin → Crystal violet → Gram's iodine → Alcohol
, C) Gram's iodine → Crystal violet → Alcohol → Safranin
D) Alcohol → Crystal violet → Gram's iodine → Safranin
Answer: A
Rationale: The Gram stain sequence is: crystal violet (primary stain), Gram's iodine
(mordant), alcohol (decolorizer), and safranin (counterstain). Gram-positive organisms
retain crystal violet-iodine complex; Gram-negative organisms take up safranin.
9. Which of the following is the primary analyte measured in a serum ferritin test?
A) Ferritin
B) Iron
C) Transferrin
D) Total iron-binding capacity
Answer: A
Rationale: Serum ferritin is the primary analyte measured to assess iron stores. It is an
acute-phase reactant and can be elevated in inflammation, but low ferritin is highly
specific for iron deficiency.
10. Which of the following is a tumor marker for colorectal cancer?
A) CEA
B) CA-125
C) PSA
D) AFP
Answer: A
Rationale: Carcinoembryonic antigen (CEA) is a tumor marker for colorectal cancer. It is
used for monitoring treatment and detecting recurrence, not for screening. CA-125 is for
ovarian cancer, PSA for prostate, AFP for liver and germ cell tumors.
11. A 24-hour urine specimen is being collected for creatinine clearance. What is
the most important instruction to give the patient?
A) Collect all urine over 24 hours, discarding the first morning void
B) Collect only the first morning void
C) Collect urine only after meals
D) Collect urine for 12 hours
Complete 600 Real Questions {2026}
This professional certification resource is a premier test bank designed for candidates
preparing for the American Medical Technologists (AMT) Medical Laboratory Scientist
(MLS) certification exam. It features a comprehensive bank of 600 realistic exam
questions accompanied by 100% verified correct answers and detailed analytical
rationales. Practicing with these target parameters ensures deep competence across
the core work domains—including Hematology, Clinical Chemistry, Blood Banking, and
Lab Safety—guaranteeing you comfortably secure the required 70 scaled passing
score on your first attempt
1. A laboratory technician is performing a manual platelet count using a
hemocytometer. The platelet count in 5 small squares (each 0.2 mm² area, 0.1 mm
depth) is 150. The dilution is 1:100. What is the platelet count in platelets/μL?
A) 30,000
B) 150,000
C) 300,000
D) 1,500,000
Answer: B
Rationale: The formula for platelet count is: (cells counted × dilution × 10) / number of
small squares counted. Here, (150 × 100 × 10) / 5 = 30,000. Wait, that gives 30,000? Let's
recalculate: 150 × 100 = 15,000; × 10 = 150,000; / 5 = 30,000. That would be option A.
But standard platelet count uses 5 small squares, each 0.2 mm², depth 0.1 mm, so volume
per square = 0.02 μL. Total volume counted = 5 × 0.02 = 0.1 μL. Cells counted = 150. So
concentration = .1 = 1500 cells/μL in diluted sample. Multiply by dilution 100 =
150,000. So answer is B. The formula I used incorrectly multiplied by 10. Correct formula:
cells/μL = (cells counted × dilution) / volume counted (μL). Volume = 5 × 0.2 × 0.1 = 0.1
μL. So (150 × 100) / 0.1 = 150,000. So B is correct.
2. Which of the following is the correct formula for calculating the anion gap?
A) (Na⁺ + K⁺) − (Cl⁻ + HCO₃⁻)
B) (Na⁺) − (Cl⁻ + HCO₃⁻)
,C) (Na⁺ + Cl⁻) − (K⁺ + HCO₃⁻)
D) (Na⁺ + HCO₃⁻) − (Cl⁻ + K⁺)
Answer: B
Rationale: The anion gap is calculated as serum sodium minus the sum of chloride and
bicarbonate: Na⁺ − (Cl⁻ + HCO₃⁻). Potassium is sometimes included but is not standard in
most clinical calculations. Normal anion gap is 8–12 mEq/L.
3. A patient with suspected von Willebrand disease has a prolonged bleeding time
and normal platelet count. Which of the following tests is most specific for
confirming the diagnosis?
A) Platelet aggregation studies
B) von Willebrand factor antigen (vWF:Ag)
C) Prothrombin time (PT)
D) Activated partial thromboplastin time (aPTT)
Answer: B
Rationale: von Willebrand disease is diagnosed by measuring von Willebrand factor
antigen (vWF:Ag), vWF activity (ristocetin cofactor), and factor VIII levels. Platelet
aggregation may show decreased response to ristocetin. PT and aPTT are usually normal
or mildly prolonged.
4. Which of the following is the most common cause of a falsely elevated
creatinine result?
A) Hemolysis
B) Lipemia
C) Icterus
D) High-dose ascorbic acid
Answer: A
Rationale: Hemolysis can falsely elevate creatinine due to release of intracellular
creatinine and interference with certain assays. Lipemia and icterus can also interfere but
are less common. Ascorbic acid typically causes falsely low creatinine.
5. A cerebrospinal fluid (CSF) specimen is collected in three tubes. Which tube is
typically used for cell count and differential?
,A) Tube 1
B) Tube 2
C) Tube 3
D) Any tube
Answer: B
Rationale: Tube 1 is usually used for chemistry and serology, tube 2 for cell count and
differential, and tube 3 for microbiology. This sequence minimizes contamination from the
tap and ensures optimal specimen quality.
6. Which of the following is a selective medium for Gram-negative bacilli?
A) Blood agar
B) MacConkey agar
C) Chocolate agar
D) Thioglycollate broth
Answer: B
Rationale: MacConkey agar is a selective and differential medium for Gram-negative
bacilli. It contains bile salts and crystal violet to inhibit Gram-positive organisms and
lactose to differentiate lactose fermenters.
7. A patient has a positive direct antiglobulin test (DAT) and evidence of
hemolysis. Which of the following is the most likely cause?
A) Autoimmune hemolytic anemia
B) Hemolytic transfusion reaction
C) Hemolytic disease of the newborn
D) All of the above
Answer: D
Rationale: A positive DAT indicates that antibodies or complement are attached to the
patient's red blood cells. Causes include autoimmune hemolytic anemia, hemolytic
transfusion reactions, and hemolytic disease of the newborn.
8. Which of the following is the correct sequence for performing a Gram stain?
A) Crystal violet → Gram's iodine → Alcohol → Safranin
B) Safranin → Crystal violet → Gram's iodine → Alcohol
, C) Gram's iodine → Crystal violet → Alcohol → Safranin
D) Alcohol → Crystal violet → Gram's iodine → Safranin
Answer: A
Rationale: The Gram stain sequence is: crystal violet (primary stain), Gram's iodine
(mordant), alcohol (decolorizer), and safranin (counterstain). Gram-positive organisms
retain crystal violet-iodine complex; Gram-negative organisms take up safranin.
9. Which of the following is the primary analyte measured in a serum ferritin test?
A) Ferritin
B) Iron
C) Transferrin
D) Total iron-binding capacity
Answer: A
Rationale: Serum ferritin is the primary analyte measured to assess iron stores. It is an
acute-phase reactant and can be elevated in inflammation, but low ferritin is highly
specific for iron deficiency.
10. Which of the following is a tumor marker for colorectal cancer?
A) CEA
B) CA-125
C) PSA
D) AFP
Answer: A
Rationale: Carcinoembryonic antigen (CEA) is a tumor marker for colorectal cancer. It is
used for monitoring treatment and detecting recurrence, not for screening. CA-125 is for
ovarian cancer, PSA for prostate, AFP for liver and germ cell tumors.
11. A 24-hour urine specimen is being collected for creatinine clearance. What is
the most important instruction to give the patient?
A) Collect all urine over 24 hours, discarding the first morning void
B) Collect only the first morning void
C) Collect urine only after meals
D) Collect urine for 12 hours
