Gene frequencies of platelet-specific antigens in Croatian population.

The human platelet antigens (HPA) are genetically defined polymorphisms expressed on platelet membrane glycoproteins. As platelet antigens are very important in several clinical situations and in population genetics, we used the polymerase chain reaction with sequence-specific primers (PCR-SSP) to investigate HPA-1, -2, -3 and -5 allele frequencies in the Croatian population. The HPA frequencies obtained in 219 Croatians were: 1a-0.854, 1b-0.146, 2a-0.890, 2b-0.110, 3a-0.575, 3b-0.425, 5a-0.895 and 5b-0.105. These data are similar to the frequencies reported in most European studies with some significant differences in HPA-2 when compared with the Dutch and German population, in HPA-3 when compared with the Swiss population and in HPA-5 when compared with the Finnish population. The three most common condensed HPA genotypes in the Croatian population were: HPA-1a/a, -2a/a, -3a/b, -5-a/a (0.283), HPA-1a/a, -2a/a, -3a/a, -5-a/a (0.137) and HPA-1a/b, -2a/a, -3a/b, -5-a/a (0.087). Data obtained in this study can be used for better understanding and treatment of immune-mediated platelet disorders in our population.

Discrepancies between APTT results determined with different evaluation modes on automated coagulation analyzers.

Modern photo-optical coagulometers collect optical data in the form of reaction curves and offer a possibility to determine clotting times at different points of clot formation by using different evaluation modes. The objectives of this study were to determine the possible impact of an evaluation mode on activated partial thromboplastin time (APTT) results and to investigate potential benefits from visual inspection of obtained reaction curves. APTT was determined by using actin FS as reagent on two coagulometers (Siemens Medical Solutions) in 174 plasma samples with three different evaluation modes: fixed absorbance (FA), drifting baseline (DB), and point of inflexion (POI) on Behring coagulation timer (BCT), and with DB mode on Behring coagulation system (BCS). Statistically significant difference of APTT results applying the Friedman's test (P<0.0001) followed by Dunn's multiple comparison test (P<0.05) was obtained in all tested samples between POI mode and all other evaluation modes, independently of analyzer used. The differences obtained indicated that laboratory professionals must be aware of possible different evaluation modes on different analyzers, and establish evaluation mode-specific reference intervals. Moreover, correctness of a reported result could be confirmed only by visual analysis of the reaction curve.