I had the pleasure of meeting Norbert Bennattar, Directeur General of Cryopep, Montpellier, France while attending the International Society on Thrombosis and Haemostasis biennial meeting in Amsterdam, July 1–4, 2013. Mr. Bennattar posed a question I couldn’t answer. When performing the dilute Russell viper venom time (DRVVT) assay for lupus anticoagulant (LA), the operator begins with a screening assay. When prolonged above the upper limit of the reference interval, the operator then follows up with a high-phospholipid confirmatory reagent. The results of the confirmatory assay are expected to be shorter than the screen, owing to the higher concentration of phospholipid, and if the ratio of screen to confirmatory assay exceeds 1.2 (or a locally computed ratio that is close to 1.2), LA is confirmed. However, Mr. Bennattar reported on instances in which the patient’s screen was prolonged and confirmatory reagent produced a result that was longer than the screening assay (creating a ratio <1), and he asks, what may account for this, and is this a common occurrence?