Frequency of icteric interference in clinical chemistry laboratory tests and causes of severe icterus

Abstract

Objectives The aims of this study were to identify the causes of severe icterus in an academic medical center patient population and to assess the impact of icterus on clinical chemistry testing using assay package insert thresholds. Design and Methods : In this retrospective study at an academic medical center core clinical laboratory, icteric, hemolysis, and lipemia indices were available for all serum and plasma chemistry specimens analyzed on Roche Diagnostics cobas 8000 analyzers over a 12-month period, encompassing 414,502 specimens from 94,081 unique patients (51,851 females; 42,230 males) including children, inpatient, outpatient, and emergency department patients. Extensive chart review was done for all 57 patients (4 pediatric, 53 adult; 534 total specimens) who had one or more samples with an icteric index of 40 or higher (defined as severe icterus). Results Specimen icteric index exceeded package insert icteric index thresholds in 0.14% of clinical chemistry assays, with the highest number of instances for creatinine (1358 samples, 0.6% of total tests), total protein (1194 samples, 2.2%), and ammonia (161 samples, 3.9%). The 57 patients with an icteric index of 40 or higher accounted for 49.7% of all instances where the icteric index exceeded the specific assay package insert limit. The most common etiologies of this group of 57 patients were alcohol-related liver disease (34 patients), biliary tract disease (7 patients), and neoplasms (6 patients). Conclusions Approximately half of all instances where specimen icteric index exceeded assay package insert thresholds occurred in a small cohort of patients with severe liver/biliary tract disease.

Bivalirudin Monitoring in Pediatric Ventricular Assist Device and Extracorporeal Membrane Oxygenation: Analysis of Single-Center Retrospective Cohort Data 2018–2022

“…Despite distinctly different methodologies to functionally measure bivalirudin, the two assays correlated strongly with each other. Ultimately, the Bival dTT was chosen for use in our clinical practice due to spectrophotometric interference observed at high bilirubin concentrations with the chromogenic assay, which has been reported as a limitation of this type of testing (12, 13). Identification of a reliable, readily available monitoring assay is an important step in improving the safety of bivalirudin administration and optimally balancing hemostasis in ECMO and VAD patients.…”

Definition of icteric interference index for six biochemical analytes

“…Icterus is one of the most frequent endogenous interferences in clinical laboratories, caused by the presence of bilirubin ( 2 , 3 ). Mainali et al , described in their study that 0.14% of clinical chemistry assays presented bilirubin interferences ( 4 ). The other most common endogenous interferences are haemolysis, which causes the release of cellular content, and lipaemia, because of the produced turbidity.…”