Standardization Of Modes Of Prothrombin Time Reporting In Patients With Liver Disease Associated With Viral Hepatitis

Objective:The aim of this study is to assess the validity of the INR system as Standardization of modes of promrombin time reporting for patients with liver disease by comparing the difference of levels of coagulation factors of patients with liver disease and oral anticoagulant, and to investigate standardization of modes of PT reporting in patients with liver disease measured with different thromboplastin reagents by the use of various methods of expression,i.e.prothrombin time(PTs), prothrombin activity percentage (PTp), prothrombin time ratio(PTr) and International Normalized Ratio(INR.).Methods:(1)61 patients with liver disease associated with viral Hepatitis were chosen , 41 with liver cirrhosis,20 with chronic liver failure .Control patients were on warfarin therapy(n=40). Venous blood was collected into Vacutainer tubes containing 3.27% buffered trisodim citrate.The samples were centrifuged at 3000rpm for 10 min. PT test were performed using six thromboplastin reagents of different source and different ISI (Neoplastine CI PLUS, Nycoplastin鈩? Simplastin Excel S, implastin HTF, Simplastin Excel, Innovin ) .and expressed in seconds(PTs) ,ratio(PTr),activity percentage (PTp)and International Normalized Ratio(INR). 40 healthy individuals (20 male,20 female) were examined, for calibration and determination of mean normal prothrombin time (MNPT). the PT calibration curves were obtainde by the use of the same pool of plasma of 40 samples collected from healthy subjects mentioned above (dilutions 1:1,1:2,1:3 and 1:4 in owren koller buffer), for each thromboplastin reagent. The mean normal prothrombin time (MNPT) was determined for each thromboplastin reagent using the same 40 samples collected from healthy subjects mentioned above by calculating median value.(2)Fib and coagulation factors IK V, VII, IX, X were determined in patients with liver disease and oral anticoagulants patients with similar INR to compare the difference of levels of coagulation deficiencies in these two groups.Results: In patients with liver disease , PTr and PTp determined for each subject using the six different thromboplastin reagents were not significantly different.(F=1.992, p=0.079; F=1.289, p==0.268 respectively) while INR and PTs were significantly different.(F=2.497, p=0.031; F=8.491, p=0.0001 , respectively ) .Moreover ,the analysis of interchangeability by regression lines between the six thromboplastin reagents showed that when PTp was used, the high conformity was existed between reagents, while PTr, PTs and INR were used ,large discrepancies were found between reagents.In the control population on warfarin therapy, the INR values for the subjects were not significantly different[F=2.002, p=0.084]while PTs,PTr and PTp were significantly different.[F=30.541, p=0.0001; F=19.909, p=0.0001; F=10.037, p=0.0001 respectively.].the high interchangeability of the results measured with different thromboplastin reagents was obtained when the results were expressed by INRwhile discrepancies were noted between reagents when PTp,PTr and PTs were used.(2)In similar INR values ,levels of coagulation factors IK V, VII, IX, X of patients with liver disease decreased significantly and degree of decrease was conformity (mean levels: 19.5, 24.6, 26, 31, 27 respectively); levels of coagulation factors IK VII, IX, X of population on warfarin therapy decreased significantly, but degree of decrease was not conformity, factor X markedly decreased ,then factor IK VII, IX. Synthesis of factor V is not dependent on vitamin K, so factor V was normal.. Fibrinogen (p=0.0001) , factors V (p=0.0001), VII (p=0.0001) and X (p=0.004) were significantly different between the both groups using Mann-Whitney analysis; Factors II and IX were not statistically different (p=0.383, p= 0.130 respectively).Conclusions: The INR system is not valid for comparison of patients with liver disease which may be due to different factor deficiencies associated with liver disease as compared with patients on oral anticoagulant therapy., Activity percentage expression may b...