Noninvasive determination of liver collagen content in chronic hepatitis. Multivariate regression modeling with blood chemical parameters as variables.

To evaluate the diagnostic utility of blood biochemical parameters in assessing degree of hepatic fibrosis, serum levels of aminoterminal type III procollagen peptide (P III P), type IV collagen (IV-collagen), 7S domain of type IV collagen (7S-collagen), and hyaluronan (HA) were measured in 54 patients with chronic viral liver disease. Liver collagen content was quantified by a computer-assisted image analysis method. Significant correlations were found between the amount of collagen in the liver and serum levels of P III P (r = 0.482; P < 0.02), IV-collagen (r = 0.705; P < 0.001), 7S-collagen (r = 0.771; P < 0.001), and HA (r = 0.595; P < 0.001). To optimize diagnostic efficacy, we applied multivariate regression analysis to the combined results obtained for these blood biochemical parameters and some additional laboratory tests. The correlation coefficient obtained from the application of this model was 0.809. To measure the predictive value of the proposed model, we used it to estimate collagen content in an additional 16 patients with chronic liver disease and compared the estimated to the actual amount of collagen determined by direct measurement. The correlation coefficient was 0.937. These results suggest that application of the model would be useful for the assessment of collagen content of fibrotic liver.