AMT MLS Exam Flashcards

Q: How many questions are on the AMT MLS exam?

The current AMT MLS outline specifies 210 four-option, single-best-answer multiple-choice items. The testing limit is 3.5 hours, and AMT notes that an exam may include unidentified unscored pretest items.

Q: What score is required to pass the AMT MLS exam?

A scaled score of 70 on AMT's 0-100 scale is required. It is not 70% correct. AMT's current candidate handbook reports that 61% of MLS examinees passed in 2025.

Q: Who is eligible for AMT MLS certification?

Applicants must satisfy one of AMT's current Education, MLT or Military, or Alternate Education routes. Each route requires a bachelor's degree plus specified laboratory education, clinical rotations, training, or qualifying experience.

Q: What is the AMT MLS retake policy?

After a failed attempt, a candidate must wait at least 45 days and retake the entire examination. AMT permits no more than four attempts for a specific certification discipline, so the fourth attempt is the final allowed attempt under the current policy.

Q: How are these 50 cards distributed across the AMT MLS outline?

Using AMT's official 210-question work-area counts, this set uses the closest whole-card allocation: 10 General Laboratory, 9 Chemistry, 8 Hematology, 2 Coagulation and Hemostasis, 2 Immunology and Serology, 5 Immunohematology, 4 Blood Banking and Transfusion Services, 6 Microbiology, and 4 Urinalysis and Body Fluids cards.

Q: How is AMT MLS certification maintained?

Active certification requires annual renewal and compliance with AMT's three-year Certification Continuation Program cycle. MLS certificants need 45 CCP points during each three-year cycle.

Question 1

What does the coefficient of variation measure in laboratory QC?

Accepted Answer

Relative imprecision: CV% equals standard deviation divided by the mean, multiplied by 100. A lower CV indicates results clustered more tightly around the mean.

Question 2

How do random and systematic analytical error differ?

Accepted Answer

Random error increases unpredictable scatter and reduces precision; systematic error produces a consistent bias or trend and reduces accuracy.

Question 3

How does calibration differ from quality control?

Accepted Answer

Calibration establishes the relationship between instrument response and known values; quality control checks whether the calibrated system remains stable during routine testing.

Question 4

What is the core patient-identification rule before specimen collection?

Accepted Answer

Match at least two patient-specific identifiers to the order and label the specimen in the patient's presence; a room number is not an identifier.

Question 5

How do serum and plasma differ?

Accepted Answer

Serum is the liquid remaining after blood clots and lacks consumed clotting factors; plasma comes from anticoagulated blood and retains clotting factors, including fibrinogen.

Question 6

What result pattern suggests EDTA contamination of a chemistry specimen?

Accepted Answer

Unexpectedly high potassium with low calcium often suggests potassium-EDTA carryover because the additive supplies potassium and chelates calcium.

Question 7

Why can hemolysis falsely increase a measured potassium result?

Accepted Answer

Red blood cells contain much more potassium than plasma, so in-vitro cell rupture releases intracellular potassium into the specimen.

Question 8

Why must the phlebotomy order of draw be followed?

Accepted Answer

It reduces carryover of tube additives into later specimens, which could alter results or interfere with the intended assay.

Question 9

What principle underlies standard precautions in the laboratory?

Accepted Answer

Treat blood and other potentially infectious material as capable of transmitting infection, then apply appropriate hand hygiene, barriers, and sharps controls.

Question 10

What is the purpose of a delta check?

Accepted Answer

It compares a patient's current result with prior results to flag a change that may reflect true clinical deterioration, specimen error, or misidentification.

Question 11

What relationship does the Beer-Lambert principle describe?

Accepted Answer

Within an assay's linear range, absorbance is directly proportional to the concentration of the light-absorbing analyte when path length and wavelength are controlled.

Question 12

Why is serum creatinine used in estimated glomerular filtration rate?

Accepted Answer

Creatinine concentration reflects renal clearance, so equations combine it with patient variables to estimate filtration; the estimate has limitations when creatinine production is atypical.

Question 13

How do hepatocellular and cholestatic chemistry patterns differ?

Accepted Answer

Hepatocellular injury usually causes a greater relative rise in AST and ALT; cholestasis produces a greater relative rise in alkaline phosphatase, often supported by GGT.

Question 14

What period of glycemia does hemoglobin A1c mainly reflect?

Accepted Answer

Roughly the preceding two to three months, with more influence from recent weeks because circulating red cells have different ages.

Question 15

Why is cardiac troponin preferred for detecting myocardial injury?

Accepted Answer

Cardiac troponin is more specific to myocardial injury than older enzyme markers; interpretation depends on the value, serial change, assay cutoff, and clinical context.

Question 16

How is the basic serum anion gap calculated?

Accepted Answer

Sodium minus the sum of chloride and bicarbonate. It estimates unmeasured ions and helps classify metabolic acidosis.

Question 17

What blood-gas pattern defines primary metabolic acidosis?

Accepted Answer

A primary decrease in bicarbonate lowers pH; appropriate respiratory compensation lowers PCO2 through increased ventilation.

Question 18

What does a narrow monoclonal spike on serum protein electrophoresis suggest?

Accepted Answer

A concentrated, relatively uniform immunoglobulin population produced by a single clone; immunofixation is used to characterize the protein.

Question 19

What thyroid pattern is typical of primary hypothyroidism?

Accepted Answer

High TSH with low free T4 because the thyroid fails and the pituitary increases stimulation in response.

Question 20

How does mean corpuscular volume classify anemia?

Accepted Answer

MCV classifies red cells as microcytic, normocytic, or macrocytic by their average volume; it narrows the differential but does not establish the cause alone.

Question 21

What does an increased reticulocyte count indicate in anemia?

Accepted Answer

An active marrow response to red-cell loss or destruction, provided the count is interpreted relative to the degree of anemia and red-cell maturation time.

Question 22

What ferritin pattern supports iron deficiency?

Accepted Answer

A low ferritin strongly supports depleted iron stores; a normal or high value does not exclude deficiency when inflammation elevates ferritin.

Question 23

What smear pattern suggests megaloblastic anemia?

Accepted Answer

Macro-ovalocytes with hypersegmented neutrophils, reflecting impaired DNA synthesis such as vitamin B12 or folate deficiency.

Question 24

What is the significance of an Auer rod in a blast?

Accepted Answer

It supports myeloid differentiation and therefore an acute myeloid leukemia lineage rather than acute lymphoblastic leukemia.

Question 25

Which molecular finding characterizes classic chronic myeloid leukemia?

Accepted Answer

The BCR::ABL1 fusion, usually created by the t(9;22) Philadelphia chromosome, produces constitutive tyrosine-kinase activity.

Question 26

What can cause thrombocytopenia with platelet clumps on the smear?

Accepted Answer

EDTA-dependent pseudothrombocytopenia. The count should be investigated and, when appropriate, repeated with an alternate anticoagulant under laboratory procedure.

Question 27

Why can a sickle-solubility screen not distinguish sickle trait from sickle cell disease?

Accepted Answer

It detects the presence of hemoglobin S but does not quantify or separate hemoglobin fractions; a hemoglobin separation method is needed for classification.

Question 28

What isolated coagulation pattern is expected with a factor VII deficiency?

Accepted Answer

A prolonged PT with a normal aPTT because factor VII belongs to the extrinsic pathway assessed by PT.

Question 29

How is a coagulation mixing study interpreted?

Accepted Answer

Correction after mixing patient plasma with normal plasma suggests a factor deficiency; failure to correct suggests an inhibitor, though time-dependent inhibitors require incubated interpretation.

Question 30

How do IgM and IgG typically differ during an immune response?

Accepted Answer

IgM usually appears first and is efficient at complement activation; class-switched IgG predominates later and provides longer-lived, higher-affinity systemic immunity.

Question 31

What does a fourth-generation HIV screening assay detect?

Accepted Answer

HIV-1/2 antibodies plus HIV-1 p24 antigen, shortening the detection window compared with antibody-only screening; a reactive result requires the recommended supplemental algorithm.

Question 32

How do forward and reverse ABO typing complement each other?

Accepted Answer

Forward typing detects A or B antigens on patient red cells; reverse typing detects expected anti-A or anti-B in patient plasma and helps reveal discrepancies.

Question 33

How do the direct and indirect antiglobulin tests differ?

Accepted Answer

The DAT detects immunoglobulin or complement already coating red cells in vivo; the IAT detects serum antibodies that can bind reagent red cells in vitro.

Question 34

What does a positive autocontrol suggest during red-cell antibody identification?

Accepted Answer

The patient's plasma reacts with the patient-cell sample. An autoantibody is common, but recently transfused donor cells may carry an alloantigen; correlate with the DAT, transfusion history, and panel pattern.

Question 35

What is the purpose of a serologic crossmatch?

Accepted Answer

To test recipient plasma against donor red cells for incompatibility that could cause an adverse transfusion reaction.

Question 36

What is the purpose of Rh immune globulin?

Accepted Answer

To prevent an eligible RhD-negative person from becoming actively immunized to RhD after exposure to RhD-positive red cells; it does not remove established anti-D.

Question 37

At what temperature are refrigerated red-cell components stored?

Accepted Answer

At 1-6 degrees C, with continuous temperature control under blood-bank storage requirements.

Question 38

How are routine platelet components stored?

Accepted Answer

At 20-24 degrees C with continuous gentle agitation, using the applicable dating and bacterial-risk controls for the product.

Question 39

What is the immediate response to a suspected acute hemolytic transfusion reaction?

Accepted Answer

Stop the transfusion, keep IV access with compatible saline, notify the clinical team and transfusion service, and begin the required patient and product investigation.

Question 40

Why are cellular blood components irradiated for selected patients?

Accepted Answer

Irradiation inactivates donor T lymphocytes to prevent transfusion-associated graft-versus-host disease; leukoreduction is not a substitute for this purpose.

Question 41

What does the catalase test distinguish among common gram-positive cocci?

Accepted Answer

Catalase-positive staphylococci and related genera produce bubbles with hydrogen peroxide, while streptococci and enterococci are catalase negative.

Question 42

How does MacConkey agar select and differentiate organisms?

Accepted Answer

It suppresses most gram-positive organisms and differentiates lactose fermenters, which form pink colonies, from nonfermenters.

Question 43

What makes a specimen appropriate for anaerobic culture?

Accepted Answer

It comes from a normally sterile or deep site, is protected from oxygen, and is transported promptly; superficial swabs are usually poor specimens.

Question 44

What is the basic purpose of PCR in clinical microbiology?

Accepted Answer

To amplify a specific nucleic-acid target so a small amount can be detected; RNA targets require a reverse-transcription step before amplification.

Question 45

What is the purpose of a KOH preparation in mycology?

Accepted Answer

Potassium hydroxide clears keratin and cellular debris, making fungal elements easier to visualize microscopically.

Question 46

What does the minimum inhibitory concentration represent?

Accepted Answer

The lowest tested concentration of an antimicrobial that prevents visible growth of the organism under standardized conditions.

Question 47

What does urine specific gravity estimate?

Accepted Answer

The concentration of dissolved substances relative to water; it helps assess renal concentrating ability but can be affected by large molecules such as glucose or radiographic contrast.

Question 48

What is the significance of red blood cell casts in urine?

Accepted Answer

They localize bleeding to the nephron and strongly suggest glomerular injury, especially when accompanied by dysmorphic red cells and proteinuria.

Question 49

What do white blood cell casts indicate?

Accepted Answer

Inflammation within the kidney, classically pyelonephritis or interstitial nephritis, rather than isolated lower urinary-tract inflammation.

Question 50

Why does urine bilirubin indicate conjugated rather than unconjugated bilirubin?

Accepted Answer

Conjugated bilirubin is water soluble and can be filtered into urine; unconjugated bilirubin is albumin bound and is not normally filtered.

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