Preanalytical factors of enhanced liver fibrosis (ELF™) laboratory testing: the score is affected by hemolysis

Liver fibrosis is a common condition that potentially leads to cirrhosis, liver dysfunction, and hepatocellular carcinoma. The Enhanced Liver Fibrosis (ELF™) test is a validated tool for assessing fibrosis. The influence of preanalytical factors on ELF™ test has not been described in previous literature. Thus, this study aims to investigate preanalytical factors affecting the ELF™ score. We evaluated the effects of hemolysis, icterus, and lipemia on the ELF™ score by measuring hyaluronic acid (HA), aminoterminal propeptide of type III procollagen (PIIINP), and tissue inhibitor of matrix metalloproteinase-1 (TIMP-1) concentrations and calculating the ELF™ scores in samples with interfering substances. The ELF™ scores and parameters were also compared between serum and lithium heparin plasma samples. Measurements were performed using a Siemens Healthineers Atellica IM 1600 analyzer. Hemolysis decreased PIIINP concentration by -21.3% and -40.5% in samples containing 1 and 2 g/L hemoglobin, respectively. Correspondingly, ELF™ scores decreased by 2.0% and 4.4%. By contrast, bilirubin and lipemia did not affect the ELF™ score. No difference in ELF™ scores was found between serum and plasma, but PIIINP concentration was 23.1% higher and TIMP-1 concentration was -38.3% lower in plasma compared with serum. Moderate hemolysis affects ELF™ scores, which might lead to a misinterpretation of patient results. Thus, we recommend automated hemolysis index testing for the ELF™ test. Significant differences in PIIINP and TIMP-1 concentrations between plasma and serum could affect individual patient results.