Comparison of a New Automated Kinetically Determined Fibrinogen Assay

Table 1. Range of coefficients of variation (CV) of three different fibrinogen assays (Clauss, kinetic and derived) of the external quality exercises of the years 1994, 1995 and 1996 (February-May) by ÖQUASTA in Austria CV Clauss, Exercises (n = 4) (n = 4) (n = 2) 3.5-13.3 5.8-10.3 3.1-16.0 n = Number of hemostaseologic exercises per year; data n = total number of compiled fibrinogen results of exercises per year. Dear Sir, We completely agree with Pál László, who mentioned in his letter to the editor ‘Comparison of Fibrinogen Determinations’ [1] that the most reliable procedure to compare different methods depends on the use of only one (pooled or commercially lyophilized) reference plasma for calibrations. However, and unfortunately, in clinical practice a great variety of heterogenous commercial calibrator plasmas are used [2]. In our paper [3], we used four different and for the different methods recommended calibration materials not in spite of the well-known fact of deviations from the declared value but because of this effect! As mentioned in our paper [3], we did not evaluate or compare four methods but studied the new kinetic method (using analyzer, reference and control plasmas according to the recommendation of the reagent manufacturer) in comparison with those derived from the three most frequently used and best established automated meth-