A radioimmunoassay procedure for type III procollagen: its use in the detection of hepatic fibrosis.

Recent studies suggest that the serum level of Type III procollagen (PC-III) could be a valuable, noninvasive monitor of hepatic fibrogenesis. We have developed a sensitive and specific radioimmunoassay for PC-III procollagen isolated and purified from fetal goat skin which shows high cross-reaction for human PC-III. In a double-blind study, serum samples taken from 8 normal volunteers and 50 patients at the time of liver biopsy were assayed for PC-III. Each biopsy was reviewed without knowledge of the radioimmunoassay results, and old or active fibrosis was graded on a 0 to 3 (none, minimal, moderate, severe) scale. There was a significant difference between serum concentrations of PC-III in normals (mean +/- S.D. = 72 ng per ml +/- 8) as compared to patients with biopsy evidence of active fibrosis (mean +/- S.D. = 153 ng per ml +/- 12; p less than 0.001). The serum concentration of PC-III showed a good correlation (r = 0.58; p less than 0.001) with the histological grade of active lobular fibrosis. Measurement of PC-III is a noninvasive test for detection of active fibrosis in the liver.