Catabolism and excretion of fibrinopeptide-A

Mean urinary excretion of fibrinopeptide-A (FPA) in 51 normal individuals ranging in age from 7 to 92 yr was 1.67 ± .1 (SE) μg/24 hr with no significant differences related to age or sex, though children tended to excrete less FPA. Calculation suggests that FPA urinary excretion represents 0.2%–0.5% of total FPA released from fibrinogen/24 hr. Urinary FPA eluted from gel permeation columns in the same position as 12BI-FPA. 126I-FPA (human) was cleared from dog plasma with a half-life of 3.9 min, and 0.5% of the total dose could be accounted for in the urine over a 3-hr period. FPA assay in paired plasma and 24-hr urine samples from 15 normal individuals, 16 patients with malignancy, 3 patients with other disease, and 5 patients with severe burns (several samples from each) demonstrated significant correlation between plasma FPA concentration and 24-hr urinary FPA excretion (p