Test Catalog

Test ID: FIBRO    
FibroTest-ActiTest, Serum

Useful For Suggests clinical disorders or settings where the test may be helpful

Evaluating hepatic fibrosis in chronic hepatitis C patients


Diagnosing fibrosis in carriers of chronic hepatitis B virus


Evaluating hepatic fibrosis in co-infected HIV carriers


Providing access to new-generation non-interferon treatment for hepatitis


Evaluating fibrosis in patients suffering from metabolic conditions (nonalcoholic fatty liver disease) and patients who consume excess alcohol

Testing Algorithm Delineates situations when tests are added to the initial order. This includes reflex and additional tests.

This test is a patented test algorithm developed by BioPredictive. FibroTest combines 5 standard biomarkers (gamma-glutamyltransferase, total bilirubin, alpha-2-macroglobulin, apolipoprotein A1, and haptoglobin). The ActiTest adds a marker for inflammatory activity (alanine aminotransferase: ALT). These markers are weighted depending on the patient's age and gender.


Testing is compliant with BioPredictive's technical recommendations and approvals.

Clinical Information Discusses physiology, pathophysiology, and general clinical aspects, as they relate to a laboratory test

Fibrosis and inflammatory activity are the 2 main causes of liver disease.


FibroTest-ActiTest estimates the levels of fibrosis and cirrhosis in the liver as well as the level of necroinflammatory activity. The estimation is made by measuring 6 standard serum biomarkers (gamma-glutamyl transferase, total bilirubin, alpha-2-macroglobulin, apolipoprotein A1, haptoglobin, and alanine aminotransferase). The activity score is a measure of liver inflammation caused by disease. Results from these tests are combined with the patient’s age and sex to estimate hepatic fibrosis and inflammatory activity scores.


Hepatic fibrosis is typically compared to a form of scar tissue that progresses throughout the liver. The most serious stage of fibrosis is known as cirrhosis.

Reference Values Describes reference intervals and additional information for interpretation of test results. May include intervals based on age and sex when appropriate. Intervals are Mayo-derived, unless otherwise designated. If an interpretive report is provided, the reference value field will state this.

FibroTest-ActiTest, Interpretation


FibroTest Score





No fibrosis



No fibrosis



Minimal fibrosis



Minimal fibrosis



Moderate fibrosis



Advanced fibrosis



Advanced fibrosis



Severe fibrosis (Cirrhosis)

*Boundary values can apply to 2 stages based on rounding. For example, a FibroTest score of 0.305 will round up to 0.31 and be staged F1. A FibroTest score of 0.314 will round down to 0.31 and be staged F1-F2.


ActiTest Score





No activity



No activity



Minimal activity



Minimal activity



Significant activity



Significant activity



Severe activity

*Boundary values can apply to 2 grades based on rounding. For example, an ActiTest score of 0.285 will round up to 0.29 and be graded A0-A1. An ActiTest score of 0.294 will round down to 0.29 be graded A1.



< or =18 years: 178-495 mg/dL

>18 years: 100-280 mg/dL





<12 months: No established reference values

> or =1 year: 7-55 U/L



<12 months: No established reference values

> or =1 year: 7-45 U/L




<24 months: No established reference values

2-17 years

Low: <115 mg/dL

Borderline low: 115-120 mg/dL

Acceptable: >120 mg/dL

> or =18 years: > or =120 mg/dL



<24 months: No established reference values

2-17 years

Low: <115 mg/dL

Borderline low: 115-120 mg/dL

Acceptable: >120 mg/dL

> or =18 years: > or =140 mg/dL




0-11 months: <178 U/L

12 months-6 years: <21 U/L

7-12 years: <24 U/L

13-17 years: <43 U/L

> or =18 years: 8-61 U/L



0-11 months: <178 U/L

12 months-6 years: <21 U/L

7-12 years: <24 U/L

13-17 years: <26 U/L

> or =18 years: 5-36 U/L



30-200 mg/dL



0-6 days: Refer to www.bilitool.org for information on age-specific (postnatal hour of life) serum bilirubin values.

7-14 days: <15.0 mg/dL

15 days to 17 years: < or =1.0 mg/dL

> or =18 years: < or =1.2 mg/dL

Interpretation Provides information to assist in interpretation of the test results

FibroTest-ActiTest provides a score that assesses hepatic fibrosis (F0-F4) and a score that assesses hepatic inflammatory activity (A0-A3). Interpretation of the score is provided in the report. Individual results from the 6 component tests are also provided with institution-specific reference intervals.


Fibrosis is reported relative to a scale ranging from F0-F4 (F0=no fibrosis, F1=minimal fibrosis, F2=moderate fibrosis, F3=advanced fibrosis, F4=severe fibrosis). Fibrosis scores may overlap (eg, F0/F1, F1/F2).


Activity is reported relative to a scale ranging from A0-A3 (A0=no activity, A1=minimal activity, A2=significant activity, A3=severe activity). Activity scores may overlap (eg, A0/A1, A1/A2).

Cautions Discusses conditions that may cause diagnostic confusion, including improper specimen collection and handling, inappropriate test selection, and interfering substances

Defer the test in transient situations that could modify the components of FibroTest-ActiTest, such as:

-Acute hemolysis, which could decrease haptoglobin and increase unconjugated bilirubin

-Acute hepatitis, whether drug-induced, viral (superinfection by hepatitis A virus: HAV, hepatitis B virus: HBV, Epstein-Barr virus: EBV), or autoimmune. Massive hepatic necrosis leads to a large increase of transaminases and total bilirubin.

-Acute inflammation, as with concomitant bacterial or acute viral infection: bronchopulmonary or urinary tract infection. The large increase of haptoglobin can lead to false-negative results.

-Extrahepatic cholestasis, such as gallstones


The advice of a liver disease specialist should be sought for interpretation in chronic states in which the components of the test could be modified, such as chronic hemolysis, particularly in patients with a cardiac valvular prosthesis; Gilbert disease; protease inhibitors used in HIV treatment, which can increase unconjugated bilirubin (Indinavir, Atazanavir); or gamma glutamyltransferase (GGT) and alanine aminotransferase (Ritonavir).


The interpretation of FibroTest has been validated in renal transplant patients. In patients with renal insufficiency or who are on dialysis, FibroTest had an acceptable diagnostic value, though lower than in transplanted patients.


As a general rule, isolated extreme values of 1 of the 6 components should signal caution in interpreting the results, particularly in the following cases:

-Haptoglobin below 12 mg/dL, in which hemolysis or anhaptoglobinemia (more frequent in western African patients) must be ruled out.

-Haptoglobin above 320 mg/dL, in which acute inflammation must be ruled out.

-Transaminases above 622 IU/L, in which acute hepatitis must be ruled out.

-Bilirubin above 1.75 mg/dL and GGT below 50 IU/L, in which Gilbert syndrome must be suspected.

-Alpha2-macroglobulin above 590 mg/dL


In case of discordance between a biopsy result and a FibroTest result, it is advisable to seek the advice of a liver disease specialist.


Haptoglobin is an acute-phase reactant and increases with inflammation or tissue necrosis. Low haptoglobin is normal for the first 3 to 6 months of life; testing is not performed on patients younger than 2 years-old per BioPredictive.


GGT activity is inducible by drugs such as phenytoin and phenobarbital and, therefore, elevations should not be considered indicative of liver disease until drug use is ruled out. Elevations are also seen after ingestion of alcoholic beverages. In very rare cases, gammopathy, in particular, type IgM (Waldenstrom macroglobinemia) may cause unreliable results.


Bilirubin specimens should be protected from light and analyzed as soon as possible. Grossly hemolyzed specimens should be rejected because hemoglobin inhibits the diazo reaction and falsely decreased results may be seen. Compounds that compete for binding sites on serum albumin contribute to lower serum bilirubin levels (eg, penicillin, sulfisoxazole, acetylsalicylic acid).

Clinical Reference Recommendations for in-depth reading of a clinical nature

1. BioPredictive: Technical Recommendations for FibroTest and FibroMax assays, Bio Predictive. Accessed  February 2018. Available at biopredictive.com/products/fibromax/

2. Halfon P, Bourliere M, Deydier R, et al: Independent prospective mulitcenter validation of biochemical markers (FibroTest-ActiTest) for the prediction of liver fibrosis and activity in patients with chronic hepatitis C: the fibropaca study. Am J Gastroenterol. 2006 Mar;101(3):547-555. doi: 10.1111/j.1572-0241.2006.00411.x

3. Houot M, Ngo Y, Munteanu M, Marque S, Poynard T: Systematic review with meta-analysis: direct comparisons of biomarkers for the diagnosis of fibrosis in chronic hepatitis C and B. Aliment Pharmacol Thera. 2016 Jan;43:16-29. doi: 10.1111/apt.13446

4. Anastasiou J, Alisa A, Virtue S, Portmann B, Murray-Lyon I, Williams R: Noninvasive markers of fibrosis and inflammation in clinical practice: prospective comparison with liver biopsy. Eur J Gastroenterol Hepatol. 2010 Apr;22(4):474-480. doi: 10.1097/MEG.0b013e328332dd0a

5. Martínez SM, Crespo G, Navasa M, Forns X: Noninvasive assessment of liver fibrosis. Hepatology. 2011 Jan;53(1):325-335. doi: 10.1002/hep.24013