A patient has an isolated prolonged aPTT. The result corrects into the reference interval immediately after a 1:1 mix with normal pooled plasma. Which mechanism is most likely?
1A strong time-independent inhibitor
2Heparin contamination that is neutralized by dilution
3Deficiency of one or more factors measured by the aPTT✓ 정답
4Excess tissue factor in the specimen
해설
Correction after mixing indicates that normal plasma supplied the missing activity, supporting a coagulation factor deficiency. Failure to correct would raise concern for an inhibitor or anticoagulant effect.