Accuracy of Biochemical Markers and Platelet Count for Diagnosis of Liver Fibrosis Staging in Patients with Liver Fibrosis, Loghman Hakim & Taleghani Hospitals, Tehran, Iran (2000-2004)

Liver biopsy is the best known technique for evaluation of liver fibrosis. However, alternative diagnostic methods have been investigated to replace this invasive procedure. Our aim was to assess the diagnostic performance of platelet count and biochemical markers for the staging of liver fibrosis in our patients. In a descriptive study, records of all consecutive patients who underwent liver biopsy at Loghman Hakim & Taleghani hospitals between March 2000 and March 2004 were retrospectively studied. The clinical and laboratory data were obtained from patients'' clinical records. Liver histology samples were reviewed by an expert pathologist. The platelet count, serum albumin levels, and the ratio of serum aspartate aminotransferase (AST) levels to platelet count were used as markers for fibrosis. Cutoff points for some of these markers were established using the ROC curve. One hundred thirty patients (94 males & 36 females) were studied. The AST/platelet ratio at the cutoff point 0.39 had a positive predictive value (PPV) of 0.70 and a negative predictive value (NPV) of 0.54 to differentiate patients without liver fibrosis from those with moderate fibrosis. This ratio had a PPV = 0.76 and NPV = 0.70 to differentiate patients without liver fibrosis from those with severe fibrosis when used at a cutoff point of 0.25. The platelet count at the cutoff point of 158500 was used for the distinction of mild from moderate fibrosis. The platelet count at the cutoff point of 151000 and serum albumin at the cutoff point of 3.6 were used for distinction of mild from severe fibrosis. No single marker was found to diagnose different stages of fibrosis. The AST/platelet ratio had an appropriate cutoff point to differentiate patients without liver fibrosis from patients with moderate to severe liver fibrosis. The clinical utility of these tests requires further investigation.