Which specimen uses EDTA among the listed items?

Which specimen uses EDTA among the listed items?

• A. Lipoproteins
• B. HbA1c
• C. ACTH, Catecholamines (prechilled)
• D. Glucose

Answer: (C)

EDTA is used when collecting samples that must be kept in plasma form and protected from rapid degradation, especially for labile hormones. ACTH and catecholamines are very unstable in whole blood, so they are collected in EDTA tubes and kept on ice (prechilled) to slow degradation and preserve the analytes for accurate measurement. The EDTA anticoagulant prevents clotting by chelating calcium, allowing plasma to be used for the assay. Other items don’t require this specific EDTA/prechilled handling: glucose testing uses fluoride-oxalate to inhibit glycolysis, and lipoprotein testing and HbA1c typically use other standard collection approaches. Thus, the specimen that uses EDTA in this list is the one involving ACTH and catecholamines with prechilled handling.

EDTA is used when collecting samples that must be kept in plasma form and protected from rapid degradation, especially for labile hormones. ACTH and catecholamines are very unstable in whole blood, so they are collected in EDTA tubes and kept on ice (prechilled) to slow degradation and preserve the analytes for accurate measurement. The EDTA anticoagulant prevents clotting by chelating calcium, allowing plasma to be used for the assay. Other items don’t require this specific EDTA/prechilled handling: glucose testing uses fluoride-oxalate to inhibit glycolysis, and lipoprotein testing and HbA1c typically use other standard collection approaches. Thus, the specimen that uses EDTA in this list is the one involving ACTH and catecholamines with prechilled handling.