A light blue top tube is received underfilled. What is the expected effect on coagulation testing?
1Falsely shortened PT and aPTT
2No effect if the specimen is centrifuged longer
3Hemolysis only, with no effect on clotting times
4Falsely prolonged PT and aPTT✓ 정답
해설
The coagulation tube has a fixed ratio of blood to anticoagulant. An underfilled tube leaves a relative excess of citrate, which inhibits the reaction and falsely prolongs the PT and aPTT. Extending the centrifugation time does not fix this, so the specimen must be recollected.