Background: The enhanced liver fibrosis (ELF) blood test has recently been recommended by the National Institute for Health and Care Excellence to test for advanced fibrosis in nonalcoholic fatty liver disease. The ELF test involves calculating a score from the concentrations of serum biomarkers: tissue inhibitor of matrix metalloproteinases-1 (TIMP-1), aminoterminal propeptide of procollagen type III (P3NP), and hyaluronic acid (HA). Blood samples for the ELF score are often acquired in primary care and may be stored before analysis. However, the effect of preanalytical storage on the ELF test is not known.
Methods: We conducted experiments to assess the stabilities of the ELF score, P3NP, HA, and TIMP-1 under medium- to long-term storage at −80 °C, repeated freeze-thawing, and refrigeration at 4 °C for days.
Results: Mean TIMP-1 concentrations increased during medium- to long-term storage (+16.5%) and refrigeration (+4.9%), but were stable during freeze-thawing. Mean P3NP concentrations were stable under medium- to long-term storage, but increased during refrigeration (+7.4%) and freeze-thawing (+9.3%). Mean HA concentrations decreased during medium- to long-term storage (−12.3%) but were stable during refrigeration and freeze-thawing. Despite changes in biomarker concentrations, the changes in the mean ELF score were not clinically significant and not >0.1 U (0.7%).
Conclusions: The ELF score was stable, with no clinically significant changes under common storage conditions. These findings demonstrate that the ELF score is robust in situations where analysis may be delayed.
Authors' Disclosures or Potential Conflicts of Interest: Upon manuscript submission, all authors completed the author disclosure form.
Employment or Leadership: W.M. Rosenberg, iQur Limited.
Consultant or Advisory Role: W.M. Rosenberg, Siemens Healthineers.
Stock Ownership: W.M. Rosenberg, iQur Limited.
Honoraria: W.M. Rosenberg, Siemens Healthineers.
Research Funding: This work was funded by iQur Limited and supported by researchers at the National Institute for Health Research Biomedical Research Centre University College London Hospitals.
Expert Testimony: None declared.
Patents: None declared.
Role of Sponsor: No sponsor was declared.
- Received December 12, 2016.
- Accepted February 3, 2017.
- © 2017 American Association for Clinical Chemistry