ROC curves in evaluation of serum fibrosis indices for hepatic fibrosis

AIM: Use Receiver operating characteristic (ROC) curves to find out the relationship between serum level of hyaluronic acid (HA), type III procollagen (PCIII), N-terminal procollagen III peptide (PIIINP), laminin (LN), type IV collagen (C-IV) and hepatic fibrosis, as well as to determine their value in clinical practice. METHODS: 114 serum samples from chronic hepatitis patients were assayed for fibrosis indices including HA, PCIII, PIIINP, LN and IV-C with radioimmunoassay (RIA). Liver biopsy was also performed in all these patients and the biopsy material was examined histopathologically. RESULTS: ROC curves analysis showed that area under the curve (AUC) of PIIINP, HA, PCIII, C-IV and LN was 0.800, 0.728, 0.727, 0.583 and 0.463, respectively. The analysis also showed that PIIINP (r=0.452), HA (r=0.497) and PCIII (r=0.404) have greater diagnosis performances than C-IV (r=0.238) and LN (r=0.128) according to fibrosis staging. The sensitivity of HA plus PIIINP was 55.1 %, it was the most sensitive combination. Combined three or more than three indices that based on HA, the specificity was 100 %. Using combination assays can improve the specificity, but its sensitivity was not high. Serum fibrosis indices increased as the grade of inflammation aggravated. But only PIIINP and PCIII had significant difference between G1 and G2 (PIIINP: 13.16+/-8.07 vs8.32+/-5.09; PCIII: 164.22+/-65.69 vs 138.23+/-77.63). The coefficient correlation of the results of inflammation grade and fibrosis staging to HA was 0.525 and 0.553 respectively, that to PCIII, 0.446 and 0.412, that to LN, 0.234 and 0.194, and that to IV-C, 0.363 and 0.351, respectively. CONCLUSION: Serum fibrosis indices can indicate tendency of hepatic fibrosis, but it cannot replace liver biopsy. However, as diagnostic markers, more efficient serum fibrosis indices for the diagnosis of hepatic fibrosis need to be explored.