CBC with low PLT and a smear showing platelets around neutrophils. What causes this and next action?

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Multiple Choice

CBC with low PLT and a smear showing platelets around neutrophils. What causes this and next action?

The situation is an in vitro artifact where platelets clump in the presence of EDTA, leading to a falsely low automated platelet count even though the patient’s platelets may be normal. On the smear you see platelets clustered around neutrophils, which is a classic clue that the low count is not real but due to EDTA-dependent platelet agglutination. The best next step is to draw and test again using a different anticoagulant, typically sodium citrate (or heparin). If citrate is used, the platelet count should be corrected for the dilution effect by multiplying by 1.1. This confirms whether the apparent thrombocytopenia is a true finding or an EDTA-induced artifact. A peripheral smear should be reviewed to ensure clumping is no longer present after recollection. Ignoring the clumping, assuming clot formation, or starting anticoagulant therapy would not address the laboratory artifact and could lead to unnecessary or incorrect management. Repeating with EDTA would reproduce the problem.

The situation is an in vitro artifact where platelets clump in the presence of EDTA, leading to a falsely low automated platelet count even though the patient’s platelets may be normal. On the smear you see platelets clustered around neutrophils, which is a classic clue that the low count is not real but due to EDTA-dependent platelet agglutination.

The best next step is to draw and test again using a different anticoagulant, typically sodium citrate (or heparin). If citrate is used, the platelet count should be corrected for the dilution effect by multiplying by 1.1. This confirms whether the apparent thrombocytopenia is a true finding or an EDTA-induced artifact. A peripheral smear should be reviewed to ensure clumping is no longer present after recollection.

Ignoring the clumping, assuming clot formation, or starting anticoagulant therapy would not address the laboratory artifact and could lead to unnecessary or incorrect management. Repeating with EDTA would reproduce the problem.

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