THE ROLE OF LIPIDS IN THE DETECTION OF LUPUS ANTICOAGULANT BY THE DILUTE RUSSELL VIPER VENOM TEST - ARE PLATELETS OR REAGENTS CONTAINING HEXAGONAL H-II PHASES NECESSARY

Liposomes prepared from rabbit brain extracts (RBE) and individual pur e lipids (high phosphatidyl serine content, HIPS) were compared with f rozen-thawed platelets (PLTS) in the dilute Russell Viper venom time ( dRVVt). While all three preparations demonstrated sensitivity to lupus anticoagulant (LA) the highest detection rate was seen with RBE. For confirmation of LA, high concentration RBE achieved the most efficient correction of the defect. Electron microscopy and particle sizing sho wed RBE to be small, discrete liposomes, whereas HIPS and PLTS were ag gregates of larger diameter particles. Low-angle X-ray diffraction sho wed no evidence of hexagonal H-II phase. There appears to be no specif ic requirement either for platelets or for reagents containing hexagon al H-II phases in the dRVVt. The dRVVt can be optimized by incorporati ng a simple dilute rabbit brain lipid mixture for detection of LA and a concentrated mixture as a correcting reagent.