Screening coagulation testing using the APTT: Which reagent to choose?

APTT testing is integral to hemostasis testing. A prolonged result, however, can be difficult to interpret, depending on the APTT reagent's sensitivity to the lupus anticoagulant. This often generates additional laboratory testing for both factor deficiencies and the presence of a lupus anticoagulant, and in so doing, delays patient management. We have found it useful to provide APTT testing with both a lupus anticoagulant sensitive and insensitive reagent, to facilitate the rapid exclusion of significant factor deficiencies. The following case report illustrates the utility of this approach and provides a backdrop for necessary discussions between laboratories and clinicians regarding which APTT reagent best meets their clinical need for screening hemostasis testing.