If a prenatal specimen shows thrombocytopenia with platelet clumps on smear, what is the next step in handling the sample?

If a prenatal specimen shows thrombocytopenia with platelet clumps on smear, what is the next step in handling the sample?

• A. recollect the sample in sodium citrate
• B. recollect the sample in EDTA
• C. conduct a workup for an autoimmune disease
• D. evaluate for risk of thromboembolism

Answer: (A)

Platelet clumping in EDTA anticoagulated samples can create a falsely low platelet count, known as pseudothrombocytopenia. EDTA-dependent antibodies cause platelets to aggregate in vitro, so the smear looks thrombocytopenic even though the patient’s platelets are normal. Recollecting the sample in sodium citrate avoids this clumping and provides an accurate count. If needed, count can be corrected for the dilution in citrate tubes (roughly multiply by 1.1) to compare with a standard whole-blood count. This step is essential to confirm whether there is true thrombocytopenia versus an artifact, especially in a prenatal specimen. Further workup would follow only if the citrate-based count remains low.

Platelet clumping in EDTA anticoagulated samples can create a falsely low platelet count, known as pseudothrombocytopenia. EDTA-dependent antibodies cause platelets to aggregate in vitro, so the smear looks thrombocytopenic even though the patient’s platelets are normal. Recollecting the sample in sodium citrate avoids this clumping and provides an accurate count. If needed, count can be corrected for the dilution in citrate tubes (roughly multiply by 1.1) to compare with a standard whole-blood count. This step is essential to confirm whether there is true thrombocytopenia versus an artifact, especially in a prenatal specimen. Further workup would follow only if the citrate-based count remains low.