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FibroTest-ActiTest, Serum

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Updated Test Information:

Test Description
FibroTest-ActiTest, Serum
Synonym(s)

HCV FibroSure, Liver Fibrosis; Hepatic Fibrosis; Hepatic Inflammation; Hepatitis; Liver Inflammation; Chronic Hepatitis C; Chronic Hepatitis B

Test ID
FIBRO
General Information

Useful for:



  • 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 noninterferon treatment for hepatitis

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


Testing Algorithm:



  • 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

Specimen Type

Serum

Specimen Requirements

  • Preferred: Serum Gel (SST)

  • Acceptable: Red Top

Specimen Collection / Processing Instructions

  • Centrifuge and aliquot within 2 hours of collection

  • Centrifuged serum must be light protected within 4 hours of collection. It is acceptable to draw the blood and then protect it from light after centrifugation as long as it is within 4 hours of collection.

Required Information

Age and sex are required

Stability

  • Refrigerated (preferred): 7 days

  • Frozen: 14 days

  • Ambient: 24 hours

Unacceptable Specimen Conditions

  • Gross hemolysis

  • Gross lipemia

  • Gross icterus

  • Patients < 2 years of age

Limitations

  • 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, EpsteinBarr 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).

Methodology

  • INTF: Algorithm and interpretation provided through BioPredictive

  • APOAF: Automated Turbidimetric Immunoassay

  • A2MF: Nephelometry

  • HAPTF: Nephelometry

  • ALTF: Photometric Rate, L-Alanine with Pyridoxal-5-Phosphate

  • GGTF: Photometric Rate

  • TBILF: Photometric, Diazonium Salt (DPD)

Estimated TAT

1-3 days

Testing Schedule

Monday-Saturday

Test Includes

  • INTF FibroTest-ActiTest

  • APOAF Apolipoprotein A1

  • A2MF Alpha-2-Macroglobulin

  • HAPTF Haptoglobin

  • ALTF Alanine Aminotransferase (ALT)

  • GGTF Gamma Glutamyltransferase (GGT)

  • TBILF Bilirubin, Total

Retention

7 days

CPT Code(s)

81596

Additional Information
Minimum Sample Volume

1.5 mL

Reference Range
FibroTest Score Stage Interpretation
0.00-0.21* F0 No fibrosis
0.21-0.27* F0-F1 No fibrosis
0.27-0.31* F1 Minimal fibrosis
0.31-0.48* F1-F2 Minimal fibrosis
0.48-0.58* F2 Moderate fibrosis
0.58-0.72* F3 Advanced fibrosis
0.72-0.74* F3-F4 Advanced fibrosis
0.74-1.00 F4 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 Grade Interpretation
0.00-0.17* A0 No activity
0.17-0.29* A0-A1 No activity
0.29-0.36* A1 Minimal activity
0.36-0.52* A1-A2 Minimal activity
0.52-0.60* A2 Significant activity
0.60-0.62* A2-A3 Significant activity
0.62-0.100 A3 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.

 

Test (Units) Gender Age (years) Range Interpretation
ALPHA-2-MACROGLOBULIN (mg/dL)     100 - 280  
ALT (U/L) Males ≥ 1 7 - 55  
Females 7 - 45  
APOLIPOPROTEIN A1 (mg/dL) Males > 2 ≥ 120 Acceptable
Females 2 - 17 ≥ 120 Acceptable
≥ 18 ≥ 140 Acceptable
GAMMA-GLUTAMYLTRANSFERASE (U/L) Males < 6 < 21  
7 - 12 < 24  
13 - 17 < 43  
≥ 18 8 - 61  
Females < 6 < 21  
7 - 12 < 24  
13 - 17 < 26  
≥ 18 5 - 36  
HAPTOGLOBIN (mg/dL)     30 - 200  
BILIRUBIN, TOTAL (mg/dL)   < 17 ≤ 1.0  
  ≥ 18 ≤ 1.2  

 

 

 

 

Performing Lab

Mayo

LOINC Code(s)

1975-2, 1743-4, 1835-8, 1869-7, 2324-2, 46127-7, 48795-9, 48794-2, 88447-8, 48792-6, 48793-4, 88448-6, 48767-8, 74715-4