Urinary fibrin degradation products--a three year comparative study.

Urinary fibrin degradation products (FDP) were determined by Merskey's passive haemagglutination test in 115 patients with biopsy proven chronic proliferative glomerulonephritis (GN), 94 with urinary tract infection (UTI), and 23 transplanted patients. The active GN values (12.3 microgram/ml) are significantly higher than those for latent GN (0.3 microgram/ml). Those for acute UTI (9.2 microgram/ml) are significantly higher than for chronic UTI (1.3 microgram/ml). In contrast to the reports published by others, the numerous 'false positive' and 'false negative' values make diagnosis of the activity unreliable. Some prognostic value can be expected in GN with the nephrotic syndrome (NS): patients with steroid-sensitive NS excrete no FDP and patients with steroid-resistant NS excrete larger quantities of FDP. We have confirmed that a rise in FDP level following kidney transplantation is indicative of an acute rejection crisis. However, since 10 of 27 rejections were FDP negative, the absence of FDP in the urine does not preclude rejection, so that the diagnostic value is restricted.