Utility of the I-index as a pre-screening tool for total bilirubin testing: a retrospective study in a regional hospital

Abstract Objectives This study evaluates the efficacy of the icteric index as a pre-screening tool for hyperbilirubinemia in adult patients. Methods The use of this index would help optimize the use of clinical laboratory resources. Results A retrospective analysis of 3,194 serum samples revealed a strong correlation between icteric index and total bilirubin levels (r=0.972), with an area under the ROC curve of 0.90. An index cut-off value of 1.2 yielded a sensitivity of 100 % and a specificity of 87 %. This performance guarantees the detection of the totality of hyperbilirubinemia cases and the absence of false negatives, albeit with some false positives. This method would avoid around 79 % of unnecessary total bilirubin tests, resulting in estimated annual cost savings of over 1,500 Euros. Conclusions In conclusion, the icteric index is an effective, inexpensive, and safe tool for improving the diagnostic performance of laboratory tests without compromising the quality of care.