Wide discrepancies in activated clotting times measured by two devices were detected for a patient with lupus anticoagulant in a cardiac surgery.

Introduction:: For a patient with lupus anticoagulant (LA), activated coagulation time (ACT) was measured with two different types of devices (HEMOCHRON 801 and HEMOCHRON Jr).

Case Report:: ACTs during heparinization measured with the HEMOCHRON 801 were over the range of measurement, while those with the HEMOCHRON Jr. reflected an almost normal response to heparin.

Discussion:: The phospholipid contained in an activating agent of the HEMOCHRON Jr was suggested to have counteracted the effect of LA.

Conclusion:: It was indicated that the coagulation status for LA-positive patients might be better assessed by ACT measured with phospholipid in an activating agent, although careful interpretation is required.