The activated partial thromboplastin time-clot waveform analysis in hemophilia: Does it help in differentiation?

Abstract

The clot waveform analysis (CWA) provide valuable information beyond clotting time. The present study was planned to assess whether the activated partial thromboplastin time (aPTT)-CWA can differentiate between hemophilia A (HA), hemophilia B (HB), or hemophilia A with inhibitors (HAWI). The aPTT-CWA was generated by an optical detection system (ACL-TOP™ 500 coagulation analyzer) and the other tests were performed as per instructions from the manufacturer in the kit. A total of 75 samples (47-HA, 16-HAWI, and 12-HB) with prolonged aPTT were recruited. On analyzing the quantitative aPTT-CWA data of HA (non-inhibitors) and HB samples, the width of acceleration 1 [+] peak was the differentiating finding. Among the significant parameters, the second derivative [+] peak was lower in both mild and moderate HA, equating to HB. The time for the height of 1/2 fibrin formation and width of velocity was significantly higher in mild, moderate and severe HA. The study did not show any significant differentiating finding while comparing HAWI and hemophilia A non-inhibitors (HANI). In the subgroups of HAWI and HANI with aPTT <70 s and 70-100 s, the second derivative [+] peak (2A) was higher and the time for the height of 1/2 fibrin formation (1C) was lesser in HAWI. The aPTT-CWA parameters may be supportive for the differentiation of hemophilia including its severity and the existence of inhibitors.