When collecting a blood specimen with the butterfly method and PT and PTT tests are the only tests ordered, what is the correct procedure?
A) use a single serum tube with clot activator
B) collect a sodium citrate tube first, then EDTA
C) use a discard tube, then collect a sodium citrate tube
D) collect a single blue-topped tube

Question

Quizplus · Accepted Answer

When collecting blood for PT and PTT tests, which require precise blood-to-anticoagulant ratios, using a butterfly needle system can introduce air into the first tube, potentially affecting the test results. Therefore, a discard tube is used first to ensure the accuracy of the sodium citrate tube that follows.

When Collecting a Blood Specimen with the Butterfly Method and PT