Background: Our current activated partial thromboplastin time (APTT) reagent (PTT-A) is often prolonged for unexplained reasons.
Methods: We decided to compare this reagent with an alternative reagent (Cephascreen) and with our second line APTT (Actin FS) in terms of cut-off values, sensitivity to in-vitro coagulation factor deficiencies, sensitivity to lupus
anticoagulant (LA), and in vivo sensitivity to unfractionated heparin (UFH).
Results: Actin FS, PTT-A, and Cephascreen were prolonged for FVIII level at 60%, 40%, and 40% respectively, FIX at 50%, 25%, and 35%, and FXI at 60%, 20%, and 50%. PTT-A showed the same sensitivity and specificity as Cephascreen to LA. Actin FS and PTT-A appeared less suitable to monitor UFH regarding the CLSI criteria.
Conclusions: Cephascreen fulfilled the CLSI performance criteria, with a good compromise in terms of sensitivity to factor deficiency and with a substantial reduction of complementary analysis in our routine practice.