FIB-4 With Reflex to Enhanced Liver Fibrosis (ELF)™

Serum and whole blood

Serum: 2 mL divided into two tubes, 1 mL for initial testing and 1 mL for possible reflex

Whole blood: tube filled to capacity

Serum: 1.5 mL divided into two tubes, 0.75 mL for initial testing and 0.75 mL for possible reflex

Whole blood: tube filled to capacity

Gel-barrier tube or red-top tube and lavender-top (EDTA) tube

According to the 2022 American Association of Clinical Endocrinology clinical practice guidelines, patients considered at high risk for Nonalcoholic Fatty Liver Disease (NAFLD), now known as metabolic dysfunction-associated steatotic liver disease (MASLD), should be screened for NAFLD and advanced fibrosis using the following blood-based tests:

• To assess the risk of NAFLD with liver fibrosis, use liver fibrosis prediction calculations. The preferred noninvasive initial test is the FIB-4.

• Consider persons belonging to the “high risk” group who have an indeterminate or high FIB-4 score for further workup with an ELF test.

The FIB-4 index is reported to be a simple, accurate, non-invasive and readily available laboratory test index that can help in the evaluation of patients with NAFLD for the presence of liver fibrosis, indication for liver biopsy, and other liver-related complications.

The Enhanced Liver Fibrosis (ELF™) blood test is a simple, accurate, non-invasive test that provides a simple, unitless numeric score that is generated via an algorithm for use in advanced liver fibrosis. It is indicated as a prognostic marker in conjunction with other laboratory findings and clinical assessments in patients with advanced fibrosis (F3 or F4) due to non-alcoholic steatohepatitis (NASH) to assess the likelihood of progression to cirrhosis and liver-related clinical events. Because ELF™ uses a blood sample rather than a biopsy, it can be used routinely for the same patient over time.

Clumping may cause false low platelet count. Platelet satellitism around neutrophils will cause a pseudothrombocytopenia. RBC or WBC fragments including fragmented fragile leukemic cells and neutrophil pseudoplatelets may cause falsely elevated counts.

AST and ALT: kinetic

Platelet Count: automated cell counter

ELF Reflex if performed: The ELF™ test consists of three fully automated, two-site sandwich immunoassays using direct chemiluminometric technology. The component assays use two monoclonal mouse antibodies: The first antibody is an acridinium ester-labeled antibody. The second antibody is a biotin-labeled antibody. The solid phase contains streptavidin-coated paramagnetic particles. The ELF™ score is derived from an algorithm that combines PIIINP, TIMP-1, and HA. ELF™ is a trademark of Siemens Healthcare Diagnostics.