Medical Lab Tech ASCP Exam Questions & Answers 2026 (11–20)

Question 1

Sickle cell anemia results from a single amino acid substitution in which globin chain?

TheoryPractice · Accepted Answer

Beta chain, valine for glutamic acid at position 6. Hemoglobin S arises from substitution of valine for glutamic acid at the sixth position of the beta-globin chain, causing polymerization and sickling under low-oxygen conditions.

Question 2

On hemoglobin electrophoresis at alkaline pH, which hemoglobin migrates the fastest toward the anode?

TheoryPractice · Accepted Answer

Hemoglobin A. At alkaline pH (8.6), Hgb A is the most negatively charged of the common variants and migrates fastest toward the anode, ahead of F, S, and C.

Question 3

Auer rods seen in the cytoplasm of blasts are most specific for which lineage of acute leukemia?

TheoryPractice · Accepted Answer

Myeloid (acute myeloid leukemia). Auer rods are crystallized azurophilic granules found only in myeloid blasts, supporting a diagnosis of AML rather than ALL.

Question 4

A markedly elevated WBC count with the full spectrum of granulocyte maturation and a very low leukocyte alkaline phosphatase score suggests which disorder?

TheoryPractice · Accepted Answer

Chronic myelogenous leukemia. CML shows a left-shifted granulocytic series with a characteristically LOW LAP score, whereas a benign leukemoid reaction shows a HIGH LAP score.

Question 5

The erythrocyte sedimentation rate (ESR) is primarily a nonspecific indicator of which process?

TheoryPractice · Accepted Answer

Inflammation. ESR rises with increased plasma fibrinogen and globulins that promote rouleaux and faster settling; it is a nonspecific marker of inflammation, not a diagnostic test.

Question 6

The prothrombin time (PT) primarily evaluates which coagulation pathway?

TheoryPractice · Accepted Answer

Extrinsic and common pathways. PT measures factors VII (extrinsic) plus X, V, II, and fibrinogen (common pathway); the aPTT instead evaluates the intrinsic and common pathways.

Question 7

The activated partial thromboplastin time (aPTT) is the test of choice to monitor therapy with which anticoagulant?

TheoryPractice · Accepted Answer

Unfractionated heparin. Unfractionated heparin potentiates antithrombin and prolongs the aPTT, which is the standard monitoring assay; warfarin is monitored by PT/INR.

Question 8

The INR was developed primarily to standardize the reporting of which test across different reagent lots and laboratories?

TheoryPractice · Accepted Answer

Prothrombin time. The International Normalized Ratio normalizes PT results using the ISI of the thromboplastin reagent so warfarin dosing is comparable regardless of reagent source.

Question 9

A correctly filled 3.2% sodium citrate (blue-top) coagulation tube uses what ratio of anticoagulant to whole blood?

TheoryPractice · Accepted Answer

1 part anticoagulant to 9 parts blood. The standard citrate ratio is 1:9 (one volume anticoagulant to nine volumes blood); underfilling raises the effective citrate concentration and falsely prolongs clotting times.

Question 10

Using a Neubauer hemocytometer, cells counted in the four large corner squares total 100, with a 1:20 dilution (depth 0.1 mm, area 4 mm^2). What is the approximate WBC count per microliter?

TheoryPractice · Accepted Answer

5,000/uL. Count/uL = (cells x dilution) / (area x depth) = (100 x 20) / (4 x 0.1) = 2000 / 0.4 = 5,000/uL.

Medical Lab Tech ASCP Exam Questions & Answers 2026 (11–20)

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