WHO/BS/2014.2244 Collaborative study of the 1st International Reference panel (Plasma) for Lupus anticoagulant

Overview

Nineteen laboratories from 11 different countries participated in a collaborative study to evaluate 3 plasma samples as the 1st International Reference Panel (Plasma) Lupus anticoagulant, 13/172. The candidates were prepared by titration of lupus negative and lupus positive patient plasmas to obtain a negative (12/148), a moderate positive (12/150) and a strong positive (12/152) lupus anticoagulant samples. Another lupus positive plasma sample, 96/560, was also included in the study.

All methods employed in this study found 12/148 to be lupus negative and both 12/150 and 12/152 to be lupus positive. The other lupus positive plasma, 96/560 was also confirmed as lupus positive. The ranking order of lupus positivity for the 3 lupus positive samples in all the assays were C>B>Z.