Test Details
Methodology
AST and ALT: Kinetic
Platelet Count: Automated cell counter
Result Turnaround Time
Within 1 day
Turnaround time is defined as the usual number of days from the date of pickup of a specimen for testing to when the result is released to the ordering provider. In some cases, additional time should be allowed for additional confirmatory or additional reflex tests. Testing schedules may vary.
Test Includes
Alanine aminotransferase (ALT/SGPT); aspartate aminotransferase (AST/SGOT); FIB-4 Index (by calculation); platelet count
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), now known as Metabolic Dysfunction-Associated Steatotic Liver Disease (MASLD), 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 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.
References
Custom 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.
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 Instructions
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) |
Reference Range
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
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
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 | 98488-0 | ||
| Order Code | 403604 | |||||
| Order Code Name | FIB-4 | |||||
| Order Loinc | ||||||
| Result Code | 001123 | |||||
| Result Code Name | AST (SGOT) | |||||
| UofM | IU/L | |||||
| Result LOINC | 1920-8 | |||||
| Order Code | 403604 | |||||
| Order Code Name | FIB-4 | |||||
| Order Loinc | ||||||
| Result Code | 001545 | |||||
| Result Code Name | ALT (SGPT) | |||||
| UofM | IU/L | |||||
| Result LOINC | 1742-6 | |||||
| Order Code | 403604 | |||||
| Order Code Name | FIB-4 | |||||
| Order Loinc | ||||||
| Result Code | 015172 | |||||
| Result Code Name | Platelets | |||||
| UofM | x10E3/uL | |||||
| Result LOINC | 777-3 | |||||
| Order Code | 403604 | |||||
| Order Code Name | FIB-4 | |||||
| Order Loinc | ||||||
| Result Code | 011582 | |||||
| Result Code Name | FIB-4 Index | |||||
| UofM | ||||||
| Result LOINC | 98488-0 |