Cumming A M, Wensley R T, Delamore I W
Thromb Haemost. 1986 Feb 28;55(1):58-60.
Factor VIII coagulant activity (VIII:C) has been shown by several investigators to exhibit increased stability in vitro when physiological levels of plasma ionized calcium are maintained by anticoagulation with heparin rather than citrate. An increase in initial activity of VIII:C in heparin over that of VIII:C in citrate has been reported but this has not been confirmed. In order to assay VIII:C in heparinized plasma, the heparin anticoagulant effect must be excluded without interfering with the validity of the assay. A one-stage clotting assay for VIII:C has been developed where heparin is neutralized by Polybrene, a synthetic polymerized quaternary ammonium salt. VIII:C may be accurately measured by this method which satisfies the requirements for a valid assay of parallelism and linearity.
几位研究者已表明，当通过肝素而非柠檬酸盐抗凝来维持血浆离子钙的生理水平时，凝血因子VIII促凝活性（VIII:C）在体外表现出更高的稳定性。有报道称肝素化血浆中VIII:C的初始活性高于柠檬酸盐抗凝血浆中的VIII:C，但这一点尚未得到证实。为了测定肝素化血浆中的VIII:C，必须排除肝素的抗凝作用，同时又不影响测定的有效性。现已开发出一种VIII:C的一步凝血测定法，其中肝素通过聚凝胺（一种合成聚合季铵盐）进行中和。通过该方法可准确测量VIII:C，该方法满足有效测定的平行性和线性要求。
