Lavender top tube description.

Lavender top tube description.

• A. Additive- EDTA; Centrifuge ASAP; Sample- EDTA plasma; Test- ACTH.
• B. Additive- EDTA; Centrifuge ASAP; Sample- Plasma; Test- ACTH.
• C. Additive- EDTA; Centrifuge ASAP; Sample- Serum; Test- ACTH.
• D. Additive- EDTA; Centrifuge ASAP; Sample- Whole blood; Test- ACTH.

Answer: (A)

Lavender top tubes contain EDTA, an anticoagulant that prevents blood from clotting. Because clotting is inhibited, the specimen in these tubes yields plasma after centrifugation rather than serum. ACTH testing uses plasma, and since ACTH is unstable and degrades quickly, the sample should be centrifuged promptly to separate the plasma (with EDTA) as soon as possible. That’s why the best description is: Additive—EDTA; Centrifuge ASAP; Sample—EDTA plasma; Test—ACTH. Serum would not be correct here because it comes from clotted blood, not an EDTA-treated specimen, and whole blood isn’t the preferred sample type for ACTH testing.

Lavender top tubes contain EDTA, an anticoagulant that prevents blood from clotting. Because clotting is inhibited, the specimen in these tubes yields plasma after centrifugation rather than serum. ACTH testing uses plasma, and since ACTH is unstable and degrades quickly, the sample should be centrifuged promptly to separate the plasma (with EDTA) as soon as possible. That’s why the best description is: Additive—EDTA; Centrifuge ASAP; Sample—EDTA plasma; Test—ACTH. Serum would not be correct here because it comes from clotted blood, not an EDTA-treated specimen, and whole blood isn’t the preferred sample type for ACTH testing.