Dia gnostic accuracy of the R-Factor in diff erentiating between neonatal hepatitis and biliary atresia in infants

Abstract

Introduction: Liver function test is a part of safe and aff ordable routine blood biochemical tests and provides useful information for the diagnosis and management of liver dysfunction. In this study we evaluated the value of the R factor in distinguishing between intrahepatic and extrahepatic causes of infant cholestasis. Methods: Receiver operating characteristic (ROC) analysis was performed to evaluate the diagnostic value of the R factor in each group in comparison with liver biopsy as the gold standard of diagnosis. The data were analyzed using SPSS statistical software and P < 0.05 indicated a significant difference. Results: The study included 37 neonatal hepatitis patients (group A) and 25 biliary atresia patients (group B). The R factor was calculated using the (ALT patient/ULN)/(ALP patient/ULN) formula; ROC analysis revealed that if the R factor was ≤ 0.09 the patient diagnosis would be biliary atresia with high sensitivity (92%) (p-value = 0.001). The corresponding specificity, positive predictive value (PPV), negative predictive value (NPV), diagnostic accuracy and area under the ROC curve (AUC) were 75.7%, 72%, 93%, 82% and 0.87, respectively. Conclusion: The study revealed that the R factor is a good diagnostic marker for differentiating between the most common intrahepatic and extrahepatic causes of infant cholestasis and has good diagnostic accuracy, sensitivity, specificity, PPV and NPV, in comparison with liver biopsy as the gold standard of diagnosis.