THE EFFECTS OF QUALITY AND TIMING OF VENIPUNCTURE ON MARKERS OF BLOOD-COAGULATION IN HEALTHY MIDDLE-AGED MEN

Effects of the quality and the time of venepuncture on factor VII coag ulant activity (VIIc) and the concentrations of fibrinogen, prothrombi n fragment 1 + 2 (F-1+2) and fibrinopeptide A (FPA) were sought in 266 5 men, of whom 2334 were re-examined after about one year. Venepunctur es were categorised as satisfactory, not fully satisfactory or unsatis factory according to pre-defined criteria. Neither the quality nor tim ing of the venepuncture influenced VIIc or fibrinogen concentration. H owever, at baseline and re-examination F-1+2 and FPA were increased on average by about 9% and 45% respectively when venepunctures were not fully satisfactory, and by about 11% and 100% when unsatisfactory. Pla sma collected after 1500 h had slightly but significantly lower levels of F-1+2 and FPA than samples taken earlier, possibly due to circadia n rhythm. The results emphasise the need for careful surveillance of t he venepuncture procedure and the value of FPA when using F-1+2 as a m arker of risk of thrombosis.