Influence of systematic discrepancy in coagulation tests on clinical decision

Objective To investigate discrepancies of coagulation parameters in different systems,and try to standardize or calibrate these index.Methods 247 samples were collected from patients,to observe difference of PT/INR,APTT,and FIB tested in STA-R,CA7000 and ACL-Advance,and then analyzed by Student-Newman-Keuls test.INR data was divided into 3 groups:2,2-3,and3 to make further analysis by nonparameter test.Results There were significant difference in PT,APTT and FIB(F=32.570,P0.01;F=134.076,P0.01;F=99.873,P0.01)respectively.Both PT and APTT from STA-R and CA-7000 system were correlated(r=0.984 and 0.944,all P0.01).Nonparameter test showed no difference(χ2=7.583,P0.05)of INR in three levels,when system-specific ISI was used.Fibrinogen measured by Clauss were different from that of PT-derived(F=99.873,P0.01).Moreover ACL Advance and STA-R showed good correlation(r=0.909,P0.01)in Fib,especially in low fibrinogen level.Conclusions It is difficult to minimize the difference merely by a correct formula,although good correlation lies between systems.We should continue to emphasize on the reagent quality and traceability,and pay more attention on system specialty to keep accuracy of coagulation tests.