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Laboratory Operations Flashcards

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

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  1. Which specimen handling error is the most common preanalytical variable affecting test accuracy?

    Answer: Hemolysis from improper venipuncture or sample handling

    Hemolysis is the most common and impactful preanalytical error. Red cell lysis releases intracellular contents (potassium, LDH, AST, hemoglobin), falsely elevating many analytes and interfering with spectrophotometric assays.

  2. The order of draw for multiple tube collection is designed to prevent:

    Answer: Cross-contamination of tube additives between specimens

    Order of draw prevents carryover of additives between tubes. EDTA (purple) into a coagulation tube would falsely prolong PT and aPTT; skin puncture contamination into coagulation tubes is addressed by discarding the first few drops.

  3. A laboratory is investigating a false-positive HIV immunoassay. Which confirmatory testing approach is used under the current CDC algorithm?

    Answer: HIV-1/HIV-2 antibody differentiation immunoassay, followed by HIV-1 NAT if indeterminate

    The current CDC HIV diagnostic algorithm uses a 4th generation Ag/Ab combination immunoassay for screening, followed by an HIV-1/HIV-2 antibody differentiation immunoassay for confirmation. HIV RNA (NAT) is used when the differentiation assay is indeterminate.

  4. In a clinical laboratory, what is the purpose of internal quality control (IQC) material?

    Answer: To monitor the analytical process for precision and accuracy between calibrations

    IQC materials are tested with each run to monitor ongoing analytical performance. They verify that the method is performing within acceptable precision and accuracy limits, detecting reagent deterioration, instrument malfunction, or calibration drift between formal calibrations.

  5. A patient's hemoglobin is 15.2 g/dL but the MCV is 112 fL. This combination suggests:

    Answer: Macrocytic process (likely B12 or folate deficiency)

    MCV of 112 fL (normal 80–100 fL) indicates macrocytosis. Combined with near-normal hemoglobin, this pattern suggests early macrocytic processes such as B12 or folate deficiency, liver disease, alcohol use, hypothyroidism, or medications like methotrexate or hydroxyurea.

  6. The LIS (Laboratory Information System) must be validated before clinical use. Which functions must be included in the validation?

    Answer: Interface testing, result transmission accuracy, reference range display, critical value flagging, and downtime procedures

    LIS validation must confirm that instrument interfaces correctly transmit results, calculated fields are accurate, reference ranges and units display correctly, critical value flags trigger appropriately, and backup or downtime procedures function. All must be documented before go-live.