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A CBC That Does Not Fit

An adult EDTA specimen arrives 55 minutes after collection at room temperature. The impedance and optical CBC reports an abnormal RBC distribution, RBC 2.41 × 10^6/µL, hematocrit 24.8%, hemoglobin 13.8 g/dL, mean corpuscular hemoglobin (MCH) 57.3 pg, and mean corpuscular hemoglobin concentration (MCHC) 55.6 g/dL. These internally inconsistent RBC-associated values require morphology and specimen review before release.

MCH = hemoglobin (g/dL) × 10 ÷ RBC count (× 10^6/µL), reported in pg. MCHC = hemoglobin (g/dL) × 100 ÷ hematocrit (%), reported in g/dL. In vitro RBC clumping can make the RBC count and hematocrit unreliable while hemoglobin remains plausible.

The initial smear has irregular clumps in the monolayer rather than orderly coin stacks. First describe clump distribution, surrounding single RBCs, and smear area; do not diagnose an antibody from the arrangement.

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Knowledge check 1

Which initial finding most strongly signals that the CBC needs interference review?

Choose one option.

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