title: Evaluation of a new chromogenic substrate assay for the measurement of the prothrombin time.
abstract: The chromogenic prothrombin time assay Nycotest Chrom was evaluated and compared with another chromogenic assay (Chromoquick) and with the well-known coagulometric Thrombotest. The intra-assay variation of the test was satisfying both in the normal range (CV = 3.6%) and in the therapeutical range of oral anticoagulation (CV = 3.5%). These values were somewhat higher than those of the Chromoquick test (1.3% and 1.1%) and those of the Thrombotest (2.3% and 2.5%). The inter-assay variation coefficient amounted to 3.3% in the normal range and in the therapeutical oral anticoagulation range to 4.4%. The respective values for the Chromoquick test were somewhat lower (2.2% and 3.9%), those of the Thrombotest in the normal range were also lower (2.1%), and in the therapeutical range they were much higher (9.2%). The coefficients of correlation of the Nycotest Chrom test in the therapeutical range were highest when comparing them with those for the Chromoquick test (r = 0.97; p < 0.0001) and somewhat lower in comparison with the Thrombotest (r = 0.95; p < 0.0001). The results of the three methods paralleled also in the starting phase of oral anticoagulation treatment. Storage at 4 degrees C and at 25 degrees C showed good stability of the Nycotest Chrom reagent for up to 24h. We conclude that the Nycotest Chrom assay is well suited for the measurement with a centrifugal fast analyser, which is attractive on behalf of the usually large series of request for prothrombin time measurements when monitoring oral anticoagulation therapy.(ABSTRACT TRUNCATED AT 250 WORDS)
authors.affiliation: Haematological Laboratory, De Wever Hospital, Heerlen, The Netherlands.
authors.forename: J W
authors.initials: JW
authors.lastname: van Wersch
mesh_terms: D000595:Amino Acid Sequence; D000925:Anticoagulants / Q000627:therapeutic use; D002863:Chromogenic Compounds; D005069:Evaluation Studies as Topic; D006801:Humans; D008969:Molecular Sequence Data; D011517:Prothrombin Time; D011933:Reagent Kits, Diagnostic / Q000706:statistics & numerical data*
chemical_list: D000925:Anticoagulants; D002863:Chromogenic Compounds; D011933:Reagent Kits, Diagnostic