Paper| Volume 40, ISSUE 6, P721-730, December 15, 1985

Development of a photometric assay for activated partial thromboplastin time and its application to the cobas(R) biocentrifugal analyzer

      This paper is only available as a PDF. To read, Please Download here.


      We describe a two-step procedure for APTT that can be performed on photometric devices. It includes preincubation of diluted plasma with ellagic acid and phospholipids and a starting reagent that contains calcium and a chromogenic peptide substrate for thrombin, Tos-Gly-Pro-Arg-pNA. Reaction time is recorded from addition of the starting reagent until thrombin formation occurs, and a prefixed amount of substrate is cleaved. The pattern of sensitivity to clotting factors and heparin was similar to clotting assays and the substrate used did not interfere with the activity of factor Xa. An application of the method was made for the Cobas(R) Bio centrifugal analyzer. Absorbance readings were sent to an external computer and were transformed into reaction times by a computer program. Although the results are independent on fibrinogen concentrations, from kinetic data of the reaction curve fibrinogen concentrations can be estimated. Correlation studies showed good correspondence to clotting methods (r = 0.92, n = 53) as well as an excellent precision (CV 3% for inter-assays, n = 15) and high throughput of samples (>100/h) in the automated assay.


      To read this article in full you will need to make a payment

      Purchase one-time access:

      Academic & Personal: 24 hour online accessCorporate R&D Professionals: 24 hour online access
      One-time access price info
      • For academic or personal research use, select 'Academic and Personal'
      • For corporate R&D use, select 'Corporate R&D Professionals'


      Subscribe to Thrombosis Research
      Already a print subscriber? Claim online access
      Already an online subscriber? Sign in
      Institutional Access: Sign in to ScienceDirect


        • Walenga J.
        • Fareed J.
        • Bermes E.W.
        Automated instrumentation and the laboratory diagnosis of bleeding and thrombotic disorders.
        in: 5th edition. Seminars in Thrombosis and Hemostasis. 9. 1983: 172-193
        • Becker U.
        • Jering H.
        • Bartl K.
        • Jilek F.
        Automated prothrombin time test with use of a chromogenic peptide substrate and a centrifugal analyzer.
        Clin. Chem. 1984; 30: 524-528
        • NCCLS
        Tentative guidelines for the standardized collection, transport and preparation of blood specimens for coagulation testing.
        Natl. Comm. Clin. Lab. Stand., Villanova, PA. 1981; : 103-118
      1. Normenausschuß Medizin im DIN Deutsches Institut for Normung, DIN 58910, 1980, Beuth-Verlag Berlin 30, F.R.G.

        • Becker U.
        • Bartl K.
        Eine photometrische Methode zur Bestimmung der Thromboplastinzeit mit einem chromogenen Peptidsubstrat.
        in: Roka L. Spanuth E. Neue Aspekte in der Gerinnungsdiagnostik. Schattauer Verlag, Stuttgart1984
        • Joist J.H.
        • Cowan J.F.
        • Khan M.
        Rapid loss of factor XII and XI activity in ellagic acid-activated normal plasma: role of plasma inhibitors and implications for automated activated partial thromboplastin time recording.
        J. Lab. Clin. Med. 1977; 80: 1054-1065
        • Fareed J.
        • Messmore H.J.
        • Kindel G.
        • Balis J.U.
        Inhibition of serine proteases by low molecular weight peptides and their derivatives.
        Ann. N.Y. Acad. Sci. 1981; 370: 765-785
        • Yamada K.
        • Meguro T.
        A new APTT assay employing a chromogenic substrate and a centrifugal Auto analyzer.
        Thromb. Res. 1979; 15: 351-358
        • Bostick W.D.
        • Bauer M.L.
        • Morton J.M.
        • Burtis C.A.
        Coagulation time determination with automatic multivariable analysis, by use of a miniature centrifugal fast analyzer.
        Clin. Chem. 1975; 21: 1288-1293
        • Karlsen R.L.
        • Visdal A.
        • Stensberg A.
        An automated method for Thrombotest on the ‘Cobas Bio’ centrifugal analyser.
        Scand. J. Clin. Lab. Invest. 1982; 42: 647-649
        • Andersen J.B.
        • Thorsen S.
        The application of the reaction rate analyser LKB 8600 as an automatic coagulometer.
        Scand. J. Clin. Lab. Invest. 1977; 37: 7-13
        • Tripodi A.
        • Mannucci P.M.
        Clinical evaluation of a fully automated chromogenic method for prothrombin time compared with a conventional coagulation method.
        Clin. Chem. 1984; 30: 1392-1395
        • Becker U.
        • Bartl K.
        • Wahlefeld A.W.
        A functional photometric assay for plasma fibrinogen.
        Thromb. Res. 1984; 35: 475-484
        • Lottenberg R.
        • Christensen U.
        • Jackson C.M.
        • Coleman P.L.
        Assay of coagulation proteases using peptide chromogenic and fluorogenic substrates.
        Methods in Enzymology. 1981; 80 C: 341-361