Significance of Serum Fibrin/Fibrinogen Degradation Products Measured by a Highly Sensitive ELISA Method in Renal Diseases

Tetsuo Shibata, MD, Second Department of Internal Medicine, Oita Medical University, Hasama-machi, Oita 879-55 (Japan) Dear Sir, In order to clarify the abnormalities of intraglomerular coagulation and fibrinolysis in patients with various renal diseases, urinary or serum fibrin/fibrinogen degradation products (FDP) have been examined by several methods [1,2]. We previously reported the results of measurement of urinary FDP in renal diseases using a newly established sensitive enzyme-linked immunosorbent assay (ELISA) [3]. Up to now there are few reports on abnormalities of fibrinolysis, especially serum FDP, in renal diseases. This has been perhaps related with technical problems that still exist in detecting serum FDP, and especially with low sensitivity of methods used up to now. Recently, we developed a highly sensitive new method of ELISA for serum FDP using a polyclonal antibody, and utilized it to clarify abnormalities of fibrinolysis in renal diseases. The polyclonal antibody to antihuman fíbrinogen was produced by the immunization of rabbits. The horseradish peroxidase was then conjugated to antihuman fíbrinogen IgG F(ab’)2 using the modified method of Nakane [4]. Serum FDP was measured in 102 patients with various renal diseases by a two-step sandwich ELISA. The results were as follows: (1) The sensitivity of method was 0.9 ng/ml. (2) The mean ± SD of serum FDP in normal subjects was 290 ± 74 ng/ml. (3) The serum FDP levels in chronic glomerulonephritis (CGN), nephrotic syndrome (NS), chronic renal failure (CRF), diabetic nephropathy (DM) and hemodialysis patients (HD) were S-FDP (ng/ml) 10000 H 500