MEASURING FIBRINOGEN CONCENTRATIONS IN HE ALTHY DOGS - STANDARDIZATION, COMPARISON OF METHODS AND REFERENCE VALUES

Plasma fibrinogen concentration was measured in 67 healthy, adult dogs using five different methods (gravimetry, methods described by JACOBS SON (1955) RATNOFF and MENZIE (1951), and CLAUSS (1957), and functiona l photometric assay). Apart from using linear regression and the Pears on correlation coefficient (r) in order to characterize the relation b etween different methods, reference ranges (2.5-97.5%-fractile) were c alculated for all methods. For calibration of the CLAUSS method (1957) and the photometric assay, dog plasma with a defined fibrinogen conce ntration was used. Measurements of commercial human fibrinogen standar ds yielded a good conformity with the concentrations specified by the manufacturer (values approximately 3% too low). These standards appear , therefore, to be also suited to the calibration of measurements of d og fibrinogen. The reference range for the gravimetry was 1.08-2.88 g fibrinogen per litre of plasma. A considerable conformity and close co rrelation was seen between the fibrinogen concentration measured by gr avimetry and by using methods described by JACOBSSON (1955; y = 1.088 x -0.142, r = 0.967) or CLAUSS (1957; y = 0.999 x -0.004, r = 0.973), respectively. Between the reference-method gravimetry and the photomet ric method and RATNOFF-MENZIE (1951) method, respectively, a less clos e correlation, as well as a minor conformity, was found.