FIB-4

CPT: 84450; 84460; 85049
Print Share

Synonyms

  • Cirrhosis
  • Liver Fibrosis
  • NAFLD
  • NASH

Test Includes

Alanine aminotransferase (ALT/SGPT); aspartate aminotransferase (AST/SGOT); FIB-4 Index (by calculation); platelet count


Expected Turnaround Time

Within 1 day


Related Documents

For more information, please review the literature below.

NAFLD-NASH Capabilities Brochure

AACE Guidelines in NAFLD White Paper


Specimen Requirements


Specimen

Serum (preferred) or plasma and whole blood


Volume

1 mL (serum or plasma); fill tube to capacity (whole blood)


Minimum Volume

0.5 mL (serum or plasma); 0.5 mL (whole blood)


Container

Gel-barrier tube or red-top tube or green-top (heparin) tube or lavender-top (EDTA) tube (plasma), and a separate lavender-top (EDTA) tube (whole blood)


Collection

Separate serum or plasma from cells within 45 minutes of collection; invert EDTA tube immediately 8 to 10 times once tube is filled at time of collection.


Stability Requirements

Temperature

Period

Room temperature

1 day (stability determined by manufacturer or literature reference)

Refrigerated

3 days (stability determined by manufacturer or literature reference)

Frozen

Unstable (stability determined by manufacturer or literature reference)

Freeze/thaw cycles

Unstable (stability determined by manufacturer or literature reference)


Causes for Rejection

Serum/plasma: Gross hemolysis; improper labeling

Whole blood: Hemolysis; clotted specimen, tube not filled with minimum volume; improper labeling; transfer tubes with whole blood; specimen diluted or contaminated with IV fluid; specimen received with plasma removed; specimen collected in any coagulant other than EDTA


Test Details


Use

FIB-4 index is reported to be a simple, accurate, non-invasive, and readily available laboratory test index that can help in evaluation of patients with HCV and Non-Alcoholic Fatty Liver Disease (NAFLD) for the presence of liver fibrosis indication for liver biopsy, and other liver-related complications. It was also reported to be concordant with FibroSure test results.


Limitations

Clumping may cause false low 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.


Methodology

AST and ALT: Kinetic

Platelet Count: Automated cell counter


Reference Interval

0 – 1.29: low risk for advanced liver fibrosis

1.30 – 2.67: Indeterminate risk for advanced liver fibrosis

>2.67: high risk for advanced fibrosis and for developing of other liver-related events


Additional Information

The FIB-4 index value is calculated using the 4 parameters formula:

FIB-4 = [Age(Years) x AST (IU/L)] / [Platelets (10E3/L) x ALT^.5 (IU/L)]

The FIB-4 index was reported in a study of patients with HCV infection to correctly identify patients with severe fibrosis (METAVIR F3-F4) with area under the ROC curve of 0.85. A FIB-4 index of less than 1.45 had a negative predictive value of 94.7% to exclude extensive fibrosis (F3-F4) with a sensitivity of 74.3% and a specificity of 80.1%. A FIB-4 index of greater than 3.25 had a positive predictive value of 82.1% to confirm the existence of significant fibrosis (F3-F4) with a specificity of 98.2% and a sensitivity of 37.6%. In the same study, FIB-4 index was in agreement with FibroTest (known in the US as FibroSure) test results of 92.1% for exclusion of severe fibrosis (F3-F4) using a cutoff of less than 1.45, and agreement of 76.0% for detection of severe fibrosis (F3-F4) using a cutoff of greater than 3.25.

In more recent studies of patients with NAFLD, FIB-4 index was reported to have area under ROC curve of 0.802 for prediction of advanced fibrosis (F3-F4)using slightly different cutoffs of 1.30 and 2.67. A negative predictive value for the absence of advanced fibrosis at a cutoff of 1.30 was 83% and a positive predictive value for the presence of advanced fibrosis and hazard ratio for developing liver realated events at a cutoff of 2.67 was 80% and 14.6 respectively. A liver biopsy had been appropriately avoided in 54% of cases.


References

Angulo P, Bugianesi E, Bjornsson ES, et al. Simple noninvasive systems predict long-term outcomes of patients with nonalcoholic fatty liver disease. Gastroenterology. 2013 Oct;145(4):782-789.e4.23860502
Shah AG, Lydecker A, Murray K, et al. Comparison of noninvasive markers of fibrosis in patients with nonalcoholic fatty liver disease. Clin Gastroenterol Hepatol. 2009 Oct;7(10):1104-1112.19523535
Vallet-Pichard A, Mallet V, Nalpas B, et al. FIB-4: an inexpensive and accurate marker of liver fibrosis in HCV infection. Comparison with liver biopsy and fibrotest. Hepatology. 2007 Jul;46(1):32-36.17567829

LOINC® Map

Order Code Order Code Name Order Loinc Result Code Result Code Name UofM Result LOINC
403604 FIB-4 001123 AST (SGOT) IU/L 1920-8
403604 FIB-4 001545 ALT (SGPT) IU/L 1742-6
403604 FIB-4 015172 Platelets x10E3/uL 777-3
403604 FIB-4 011582 FIB-4 Index N/A

For Providers

Please login to order a test

Order a Test

© 2021 Laboratory Corporation of America® Holdings and Lexi-Comp Inc. All Rights Reserved.

CPT Statement/Profile Statement

The LOINC® codes are copyright © 1994-2021, Regenstrief Institute, Inc. and the Logical Observation Identifiers Names and Codes (LOINC) Committee. Permission is granted in perpetuity, without payment of license fees or royalties, to use, copy, or distribute the LOINC® codes for any commercial or non-commercial purpose, subject to the terms under the license agreement found at https://loinc.org/license/. Additional information regarding LOINC® codes can be found at LOINC.org, including the LOINC Manual, which can be downloaded at LOINC.org/downloads/files/LOINCManual.pdf