Increase in glycocalicin levels in platelet concentrates stored in plasma or synthetic medium for 8 days: comparison with other platelet activation markers

Glycocalicin (GC) is a proteolytic fragment of GpIb and can conveniently be measured in supernatants of platelet concentrates (PCs) by means of a sandwich ELISA. Because of the convenience of the assay and easy sample storage, we tested its suitability as a sensitive platelet activation parameter during PC storage. Filtered PCs in plasma or additive solution were made from 5 pooled buffy coats and were subsequently stored during 8 days at 22+/-2 degrees C. Correlation coefficients (r) were calculated after comparison of GC levels with platelet parameters. A significant increase in GC concentration was found on all subsequent sampling days. PC stored in plasma showed GC levels that correlated well with the soluble P-selectin levels (r = 0.7506), P-selectin (CD62P) expression on platelet membranes (r = 0. 8843), morphology scores according to Kunicki (r = -0.7102), lactate concentrations (r = 0.9216), glucose concentrations (r = -0.8913) and beta-thromboglobulin (beta-TG) concentrations (r = 0.8913). In PCs stored in additive solution, the correlation coefficients with these markers were 0.9209 with soluble P-selectin, 0.7161 with CD62P expression, -0.7474 with morphology score, -0.8908 with glucose concentrations, 0.8923 with lactate concentrations and 0.8908 with beta-TG concentrations. The GC concentration correlates well with sensitive platelet (activation) parameters, rendering it a sensitive and convenient parameter for platelet activation