Relationship Between Total Prothrombin, Native Prothrombin and the International Normalized Ratio (INR)

Summary

Plasma levels of total prothrombin and fully-carboxylated (native) prothrombin were compared with results of prothrombin time (PT) assays for patients undergoing oral anticoagulant therapy. Mean concentrations of total and native prothrombin in non-anticoagulated patients were 119 ± 13 µg/ml and 118 ± 22 µg/ml, respectively. In anticoagulated patients, INR values ranged as high as 9, and levels of total prothrombin and native prothrombin decreased with increasing INR to minimum values of 40 µg/ml and 5 µg/ml, respectively. Des-carboxy-prothrombin increased with INR, to a maximum of 60 µg/ml. The strongest correlation was observed between native prothrombin and the reciprocal of the INR (1/INR) (r = 0.89, slope = 122 µg/ml, n = 200). These results indicated that native prothrombin varied over a wider range and was more closely related to INR values than either total or des-carboxy-prothrombin. Levels of native prothrombin were decreased 2-fold from normal levels at INR = 2, indicating that the native prothrombin antigen assay may be a sensitive method for monitoring low-dose oral anticoagulant therapy. The inverse relationship between concentration of native prothrombin and INR may help in identification of appropriate therapeutic ranges for oral anticoagulant therapy.

• References

• 1 Stenflo J, Fernlund P, Egan W, Roepstorff P. Vitamin K dependent modification of glutamic acid residues in prothrombin. Proc Natl Acad Sci USA 1974; 71: 2730-2733
• 2 Nelsestuen GL, Zytkovicz TH, Howard JB. The mode of action of vitamin K: identification of gamma-carboxyglutamic acid as a component of prothrombin. J Biol Chem 1974; 249: 6347-6350
• 3 Magnusson S, Sottrup-Jensen L, Petersen TE, Morris HR, Dell A. Primary structure of the vitamin K-dependent part of prothrombin. FEBS Lett 1974; 44: 189-193
• 4 Bajaj SP, Butkowski RJ, Mann KG. Prothrombin fragments: Ca²⁺ binding and activation kinetics. J Biol Chem 1975; 250: 2150-2156
• 5 Esmon CT, Suttie JW, Jackson CM. The functional significance of vitamin K action: difference in phospholipid binding between normal and abnormal prothrombin. J Biol Chem 1975; 250: 4095-4099
• 6 Mahotra OP, Nesheim ME, Mann KG. The kinetics of activation of normal and gamma-carboxyglutamic acid-deficient prothrombins. J Biol Chem 1985; 260: 279-287
• 7 Ganrot PO, Niléhn JE. Plasma prothrombin during treatment with dicumurol. II. Demonstration of an abnormal prothrombin fraction. Scand J Clin Lab Invest 1968; 22: 23-28
• 8 International Committee for Standardization in Haematology/International Committee on Thrombosis and Haemostasis: ICSH/ICTH recommendations for reporting prothrombin time in oral anticoagulant control. Thromb Haemostas 1985 53. 155-156
• 9 Furie B, Diuguid CF, Jacobs M, Diuguid DL, Furie BC. Randomized prospective trial comparing the native prothrombin antigen with the prothrombin time for monitoring oral anticoagulant therapy. Blood 1990; 75: 344-349
• 10 Bertina RM, van der Marel-van Nieuwkoop W, Loeliger EA. Spectrophotometric assays of prothrombin in plasma of patients using oral anticoagulants. Thromb Haemostas 1979; 42: 1296-305
• 11 Blanchard RA, Furie BC, Jorgensen M, Kruger SF, Furie B. Acquired vitamin K-dependent carboxylation deficiency in liver disease. N Engl J Med 1981; 305: 242-248
• 12 Blanchard RA, Furie BC, Kruger SF, Waneck G, Jorgensen MJ, Furie B. Immunoassays of human prothrombin species which correlate with functional coagulant activities. J Lab Clin Med 1983; 101: 242-255
• 13 Furie B, Liebman HA, Blanchard RA, Coleman MS, Kruger SF, Furie BC. Comparison of the native prothrombin antigen and the prothrombin time for monitoring oral anticoagulant therapy. Blood 1984; 64: 445-451
• 14 Esnouf MP, Lloyd PH, Jesty J. A method for the simultaneous isolation of factor X and prothrombin from bovine plasma. Biochem J 1973; 131: 781-789
• 15 Miletich JP, Broze Jr GJ, Majerus PW. The synthesis of sulfated dextran beads for isolation of human plasma coagulation factors II, IX, and X. Anal Biochem 1980; 75: 304-310
• 16 Shah DV, Swanson JC, Suttie JW. Abnormal prothrombin in the vitamin K-deficient rat. Thromb Res 1984; 35: 451-458
• 17 Meguro T, Yamada K. A simple and rapid test for PIVKA-II in plasma. Thromb Res 1982; 25: 109-114
• 18 Widdershoven J, van Munster P, De Abreu R, van Lith T, van der Putten-van Meyel M, Motohara K, Matsuda I. Four methods compared for measuring des-carboxy-prothrombin (PIVKA-II). Clin Chem 1987; 33: 2074-2078
• 19 Lox CD, Strohm GH, Corrigan Jr JJ. Radioimmunoassay of human prothrombin – the quantitation of factor II antigen. Am J Hematol 1978; 4: 261-267
• 20 Ganrot PO, Niléhn JE. Immunochemical determination of human prothrombin. Scand J Clin Lab Invest 1968; 21: 238-244
• 21 McDuffie FC, Giffin C, Niedringhaus R, Mann KG, Owen Jr CA, Bowie EJW, Peterson J, Clark G, Hunder GG. Prothrombin, thrombin and prothrombin fragments in plasma of normal individuals and of patients with laboratory evidence of disseminated intravascular coagulation. Thromb Res 1979; 16: 759-773
• 22 Niléhn JE, Ganrot PO. Plasma prothrombin during treatment with dicumarol. I. Immunochemical determination of its concentration in plasma. Scand J Clin Lab Invest 1968; 22: 17-22
• 23 Van Rijn JLML, Schmidt NA, Rutten WPF. Correction of instrument and reagent-based differences in determination of the International Normalized Ratio (INR) for monitoring anticoagulant therapy. Clin Chem 1989; 35: 840-843
• 24 Loeliger EA, Poller L, Samama M. Thomson JH, van den Besselaar AMHP, Vermylen J, Verstraete J. Questions and answers on prothrombin time standardisation on oral anticoagulant control. Thromb Haemostas 1985; 54: 515-517
• 25 Xi M, Béguin S, Hemker HC. The relative importance of the factors II, VII, IX and X for the prothrombinase activity in plasma of orally anticoagulated patients. Thromb Haemostas 1989; 62: 788-791
• 26 Andrew M, Schmidt B, Mitchell L, Paes B, Ofosu F. Thrombin generation in newborn plasma is critically dependent on the concentration of prothrombin. Thromb Haemostas 1990; 63: 27-30