Practice Test Geeks(MLS) Medical Laboratory Scientist Practice Test
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Clinical Testing & Analysis Flashcards

7 cards from real MLS practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.

Read the first 7 Clinical Testing & Analysis flashcards as text

  1. A type and screen is ordered pre-operatively. The antibody screen is positive. What is the next step?

    Answer: Perform antibody identification panel

    A positive antibody screen requires an antibody identification panel to determine the specificity of the unexpected antibody before blood is issued.

  2. In cerebrospinal fluid analysis, xanthochromia is most commonly caused by:

    Answer: Oxyhemoglobin and bilirubin from red cell breakdown

    Xanthochromia results from oxyhemoglobin and later bilirubin released as RBCs lyse after subarachnoid hemorrhage, distinguishing it from a traumatic tap.

  3. Which mycobacterium is the most common cause of pulmonary tuberculosis in immunocompetent US adults?

    Answer: Mycobacterium tuberculosis

    Mycobacterium tuberculosis is the etiologic agent of classic tuberculosis and remains the leading mycobacterial pathogen in immunocompetent individuals.

  4. A serum potassium is critically elevated. The specimen is hemolyzed. What should the laboratory do?

    Answer: Reject the specimen and request a recollect

    Hemolysis releases intracellular potassium, falsely elevating serum K⁺; the specimen must be rejected and a fresh non-hemolyzed sample collected for accurate results.

  5. Which coagulation test is used to monitor unfractionated heparin therapy?

    Answer: Activated partial thromboplastin time (aPTT)

    Unfractionated heparin potentiates antithrombin to inhibit intrinsic pathway factors, which is measured by the aPTT; therapeutic range is typically 1.5–2.5× control.

  6. On a peripheral smear, which cell morphology is most characteristic of iron-deficiency anemia?

    Answer: Microcytic hypochromic cells with pencil cells

    Iron deficiency produces small, pale RBCs (microcytic/hypochromic) with elongated pencil cells due to reduced hemoglobin synthesis.

  7. A urine culture grows >100,000 CFU/mL of a lactose-fermenting gram-negative rod. Oxidase is negative. Most likely organism is:

    Answer: Escherichia coli

    E. coli is oxidase-negative, lactose-fermenting, and is the most common cause of community-acquired urinary tract infections at significant colony counts.