Quality in laboratory diagnostics : from theory to practice

The es sen tial ele men ts of a qua li ty prog ram, spe ci fi cal ly in ter nal qua li ty con trol (IQC) and exter nal qua li ty as su ran ce (EQA), shou ld be ap plied to each la bo ra to ry as say per for med in or der to en su re te st re su lt ac cu ra cy and pre ci sion. The coa gu la tion la bo ra to ry plays an im por ta nt ro le in the diagno sis and treat me nt of in di vi dua ls wi th blee di ng or clot ti ng (i.e., throm bo tic) di sor de rs. Te st met ho do lo gies used to as se ss com mon di sor de rs or disea ses of hae mos ta sis are re viewed as we ll as the cli ni cal re le van ce of ea ch as say. The prea na lyti cal pha se of tes ti ng off e rs the grea te st op por tu ni ty for in tro du ci ng re su lt er ror in the hae mos ta sis la bo ra to ry and it is the re fo re im pe ra ti ve that sam ples are pro per ly co llec ted, tran spor ted and sto red. Samples for hae mos ta sis tes ti ng shou ld be col lec ted in 3.2% so dium cit ra te at a 9:1 blood to an ti coa gu la nt ra tio and main tai ned at room tem pe ra ture un til pro ces sed. So me te st pro ces ses su ch as pla te let fun ction tes ti ng ha ve spe cial pro ces si ng and tes ti ng require men ts. For plas ma-ba sed tes ts, cen tri fu ga tion to ob tain pla te let poor plas ma and tes ti ng shou ld ideal ly be com ple ted wit hin 4 hou rs or the plas ma fro zen. IQC mu st be per for med wi th ea ch as say, at ap prop ria te le ve ls of the ana lyte and at ap prop ria te time in ter va ls as a mea ns for as ses si ng on goi ng as say per for man ce. EQA, a peer group as ses sme nt pro ce ss that is sup ple men ta ry to IQC, off e rs in ad di tion the op por tu ni ty for eva lua tion of lo ng-te rm per for man ce of la bo rato ries, in clu di ng com pa ri so ns wi th li ke and un li ke met ho do lo gies, and of ten ser ves as an edu ca tio nal re sour ce. Par ti ci pa tion in an EQA prog ram is of ten a requi re me nt of la bo ra to ry ac cre di ta tion and the re are a mul ti tu de of EQA or ga ni za tio ns that off er prog ra ms spe ci fi c to hae mos ta sis tes ti ng with in ter na tio nal prog ra ms pro vi di ng as ses sme nt of the mo re spe cia li zed hae mos ta sis as says. The se prog ra ms pro vi de in va luab le in for ma tion on as say spe ci fi c diag nos tic er ror ra te, as say pre ci sion, ac cu ra cy, sen si ti vi ty and as ses sme nt of ove ra ll as say per for mance. The in cor po ra tion of IQC and EQA in to a la bo ra to ry prog ram can not on ly as si st in the as su ran ce that tes ti ng is re liab le and ac cu ra te but al so im pro ve the qua li ty of the tes ti ng. Key wor ds: qua li ty; hae mos ta sis; coa gu la tion; in ter nal qua li ty con trol; exter nal qua li ty as su ran ce