Therecognition ofHagemandeficiency in blood donors

Abnormally prolonged coagulation ofhumanblood invitro duetoadeficiency ofHagemanfactor was first described byRatnoff andColopy (1955). Itisa rare familial trait, knowntoaffect bothsexes, butis notassociated witha haemorrhagic tendency in vivo. Margolis (1957), Biggs, Sharp,Margolis, Hardisty, Stewart, andDavidson (1958), and Soulier, Wartelle, andMenache (1958) havecontributed toourunderstanding ofthepart played by Hagemanfactor intheactivation ofthecoagulation mechanism. Itisbelieved bytheabove workers that Hagemanfactor isnormally present intheinactive phase inplasma, butisitself activated bycontact withglass after which itreacts withplasma thromboplastin antecedent, thusinitiating further stages of thromboplastin generation. Theimportance ofrecognizing Hagemanfactor deficiency liesinitsdifferentiation fromother coagulation disorders during theperformance of tests invitro. Inadeficiency whichproduces noclinical abnormality, atruepicture ofitsincidence ismorelikely toemergefromaninvestigation ofthenormal population. TheNational BloodTransfusion Service regularly collects bloodsamples frommanythousandsofnormal volunteers andoccasional cases of Hagemandeficiency maybeencountered. Although theabnormality wouldpassunnoticed inthebottle containing anticoagulant, itisthepractice totake aclotted bloodsample fromeachdonorforlaboratory tests anditisonthis sample that thedefect may berecognized. Itisthepurpose ofthisreport to describe suchafinding andtodetail asimple test by whichthenature ofthedefect maybedemonstrated.