Clinical significance of urinary fibrinogen degradation products in renal disease: study with two methods and correlation with histological findings of intraglomerular coagulation

The investigation of fibrinogen degradation products (FDP) in urine has been suggested as a reliable method to detect the glomerular deposition of fibrin. Urinary FDP were investigated in 246 patients with renal disease by means of a latex test in 100 of them (positive in 54%); in the remaining 146 patients the Merskey method was used which gave positive results in 26% of them. A significant correlation between urinary protein excretion and FDP was only observed in those patients examined with the latex test. In patients investigated with the Merskey method, the simultaneous determination of serum FDP showed no correlation between FDP values in serum and urine. In those patients studied by means of renal biopsy, a poor correlation was observed between immunofluorescence and electron microscopic evidence of fibrin deposition and urinary FDP. In conclusion, isolated urinary FDP detection is not an index of pathologic coagulation in the glomeruli.