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A comparison of FVII:C and FVIIa assays for the monitoring of recombinant factor VIIa treatment
Author(s) -
Cid A. R.,
Lorenzo J. I.,
Haya S.,
Montoro J. M.,
CasaÑa P.,
Aznar J. A.
Publication year - 2001
Publication title -
haemophilia
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.213
H-Index - 92
eISSN - 1365-2516
pISSN - 1351-8216
DOI - 10.1111/j.1365-2516.2001.00478.x
Subject(s) - recombinant factor viia , medicine , factor vii , haemophilia , factor viia , haemophilia a , confidence interval , recombinant dna , pharmacology , tissue factor , coagulation , surgery , biochemistry , chemistry , gene
The use of recombinant factor VIIa (rFVIIa) is on the increase, not only to treat haemophilic patients with inhibitors, but also patients with other clotting disorders. However, the most appropriate method of monitoring this treatment remains a question that has yet to be resolved. We studied 24 plasma samples from patients receiving rFVIIa treatment (three had haemophilia A with inhibitors, and three a congenital FVII deficiency) and compared the results obtained from the FVII:C and FVIIa assays. Although a good correlation between the two methods was obtained ( r =0.91), the values of the FVII:C method were 1.63 higher than those of the FVIIa method, with a relatively wide margin in the interval of the FVII:C/FVIIa ratios obtained [95% confidence interval (CI) 1.38–1.88, range 0.68–3.68]. This interval became wider when we compared values of over 6 IU mL –1 , which led us to conclude that the two methods cannot be considered equivalent. As the FVIIa method specifically measures FVIIa, and FVII:C assay is known to have a wide interlaboratory variability, we believe that the FVIIa assay would be more suitable for the monitoring of rFVIIa treatment.