Serum and urine fibrinogen-fibrin-related antigen (F.R.-antigen) levels in renal disease.

The concentration of serum fibrinogen-fibrin-related antigen (F.R.-antigen) was measured in a group of 142 patients with various renal disorders, in 38 of whom urine F.R.-antigen was also estimated. Raised serum F.R.-antigen levels were present in 48% of the patients, with no particular preponderance in any diagnostic category apart from acute reversible intrinsic renal failure in which high levels were invariably present. Significantly-raised serum levels were also present in the patients with microangiopathic haemolytic anaemia and in those with the more severe degrees of renal impairment. Urine F.R.-antigen was increased in 34 of the 38 patients. The amount of F.R.-antigen in the urine correlated with the degree of proteinuria but not with the serum F.R.-antigen levels. The evidence relating to intravascular coagulation in renal disease is reviewed, and it is suggested that there is a high incidence of localized fibrinogen or fibrin degradation in the kidney, which is related more to factors such as the presence of uraemia and microangiopathic haemolytic anaemia rather than to the diagnostic category.