Abstract
The level of pregnancy-associated plasma protein-A (PAPP-A) in blood measured by rocket immunoelectrophoresis is affected by the addition of anticoagulants. When compared with levels in serum, those in heparin and sequestrene plasmas were higher, while those in sodium citrate, acid citrate dextrose and fluoride oxalate plasmas were lower. Similar results were obtained when the anticoagulants were added to serum and the effect on the measured level was dose-dependent within limits. Addition of anticoagulants to serum affected the mobility of PAPP-A in crossed immunoelectrophoresis, but this was not necessarily in keeping with the effect on rocket height. Addition of sodium chloride to serum did not influence the measured levels of PAPP-A.