A patient’s lab results show high blood urea nitrogen (BUN) and creatinine. What does this most likely indicate?

Dehydration or renal dysfunction

Which test is primarily used to assess kidney function by measuring the ability to clear creatinine from the blood?

Glomerular filtration rate (GFR)

Which cytokine is primarily responsible for the activation of T-cells?

Tumor necrosis factor-alpha (TNF-α)

AMT Medical Laboratory Scientist (MLS) Exam

Free AMT Medical Laboratory Practice Questions

10 sample questions for the AMT Medical Laboratory Scientist (MLS) Exam, with the correct answer and an explanation for each. No account needed. Try each one before you open the answer.

Sections covered on the exam: General Laboratory, Chemistry, Hematology, Coagulation and Hemostasis, Immunology and Serology, Immunohematology, Blood Banking and Transfusion Services, Microbiology, Urinalysis and Body Fluids.

Question 1 · General Laboratory
Which of the following is a required label on containers used to store biohazardous waste?
- A.Caution - Irritant
- B.Flammable Liquid
- C.Biohazard Symbol
- D.Toxic Substance
Show answer and explanation
Answer: C. Biohazard Symbol
Biohazardous waste must be clearly labeled with the biohazard symbol to ensure safety and compliance with OSHA regulations. These labels warn personnel of potential biological risks.
Question 2 · Chemistry
A patient’s lab results show high blood urea nitrogen (BUN) and creatinine. What does this most likely indicate?
- A.Hyperthyroidism
- B.Dehydration or renal dysfunction
- C.Liver failure
- D.Pancreatitis
Show answer and explanation
Answer: B. Dehydration or renal dysfunction
Elevated BUN and creatinine are key indicators of renal impairment or dehydration.
Question 3 · General Laboratory
Which stain is most commonly used to perform a reticulocyte count?
- A.Wright-Giemsa
- B.Sudan Black B
- C.Prussian Blue
- D.New Methylene Blue
Show answer and explanation
Answer: D. New Methylene Blue
Reticulocytes retain RNA that is stained by supravital dyes like New Methylene Blue, distinguishing them from mature RBCs.
Question 4 · Immunohematology
Which ABO group is considered the universal donor for red blood cell transfusions?
- A.A+
- B.B–
- C.AB+
- D.O–
Show answer and explanation
Answer: D. O–
O-negative blood lacks A, B, and Rh antigens, making it compatible for emergency transfusion to any patient when blood typing is not available.
Question 5 · Microbiology
Which of the following viruses is most commonly transmitted via fecal-oral route and causes liver inflammation?
- A.Hepatitis A virus
- B.Hepatitis B virus
- C.Hepatitis C virus
- D.Epstein-Barr virus
Show answer and explanation
Answer: A. Hepatitis A virus
Hepatitis A is a non-enveloped RNA virus transmitted via the fecal-oral route and causes acute liver inflammation.
Question 6 · General Laboratory
Total: 14 Questions (approximately 4–5 questions per topic)
Which classification level is assigned to laboratories working with Ebola virus?
- A.Biosafety Level 1 (BSL-1)
- B.Biosafety Level 2 (BSL-2)
- C.Biosafety Level 3 (BSL-3)
- D.Biosafety Level 4 (BSL-4)
Show answer and explanation
Answer: D. Biosafety Level 4 (BSL-4)
BSL-4 labs handle the most dangerous pathogens, like Ebola, requiring maximum containment procedures, including full-body, air-supplied suits and isolated facilities.
Question 7 · Chemistry
Which test is primarily used to assess kidney function by measuring the ability to clear creatinine from the blood?
- A.Blood urea nitrogen (BUN)
- B.Glomerular filtration rate (GFR)
- C.Liver function tests
- D.Serum albumin levels
Show answer and explanation
Answer: B. Glomerular filtration rate (GFR)
GFR is a key test used to evaluate kidney function, specifically how well the kidneys clear creatinine and other waste products from the blood.
Question 8 · Hematology
A peripheral blood smear reveals target cells. Which of the following is most likely?
- A.Sickle cell disease
- B.Thalassemia
- C.Iron deficiency anemia
- D.Chronic kidney disease
Show answer and explanation
Answer: B. Thalassemia
Target cells (cells with a central area of hemoglobin and a dark ring around it) are commonly seen in thalassemia, where abnormal hemoglobin synthesis occurs.
Question 9 · Immunology and Serology
Which cytokine is primarily responsible for the activation of T-cells?
- A.Interferon-gamma
- B.Interleukin-2 (IL-2)
- C.Tumor necrosis factor-alpha (TNF-α)
- D.Interleukin-10 (IL-10)
Show answer and explanation
Answer: B. Interleukin-2 (IL-2)
IL-2 is crucial for the proliferation and activation of T-cells, making it a key cytokine in the immune response.
Question 10 · Microbiology
Which blood component is most appropriate for a patient with a low platelet count due to thrombocytopenia?
- A.Packed red blood cells
- B.Platelet concentrate
- C.Fresh frozen plasma
- D.Cryoprecipitate
Show answer and explanation
Answer: B. Platelet concentrate
Platelet concentrates are used to treat or prevent bleeding in patients with thrombocytopenia (low platelet count).

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