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Test Catalog

Test ID: HCVL    
Hepatitis C Virus Antibody Confirmation, Serum

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

Confirming the presence of hepatitis C virus (HCV)-specific IgG antibodies in serum specimens that are reactive by HCV antibody screening tests

 

Distinguishing between true- and false-reactive HCV antibody screening test results

 

This test is not intended for use as an HCV antibody screening test for blood or human cells/tissue donors

 

This assay is not useful for detection of early or acute hepatitis C (<2 months from exposure) as immunocompromised patients may not develop detectable HCV antibodies in blood until 6 months after infection

 

This assay is not useful for differentiating between past (resolved) and chronic hepatitis C

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

This test is available as a confirmatory test for reactive Hepatitis C virus (HCV) antibody screening test results.

 

See Hepatitis C: Testing Algorithm for Screening and Diagnosis in Special Instructions.

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

Laboratory testing for hepatitis C virus (HCV) infection in patients and donors of organ, blood, cells, tissue, and tissue products usually begins by screening for the presence of HCV antibodies (anti-HCV) in serum, using an FDA-approved anti-HCV screening test. Specimens that are repeatedly reactive by screening tests should be confirmed by more HCV-specific tests, such as direct detection of HCV RNA by the reverse transcriptase-PCR (RT-PCR) or confirmatory detection of HCV antibodies by serologic assays using recombinant HCV-specific antigens. In patients with reactive HCV antibody screening test results but negative or undetectable HCV RNA test results, HCV antibody confirmatory tests would be useful to distinguish between true- and false-reactive HCV antibody screening test results.

 

HCV antibodies are usually not detectable during the first 2 months following infection, and they are usually detectable by the late convalescent stage (>6 months after onset) of infection. These antibodies do not neutralize the virus, and they do not provide immunity against this viral infection. Loss of HCV antibodies may occur in the years following resolution of infection.

 

Despite the value of serologic confirmation of HCV infection, several limitations of this test exist:

-There may be a long delay (up to 6 months) between exposure to the virus and development of detectable HCV antibodies, especially in immunocompromised patients

-A positive test result does not distinguish between past (resolved) and chronic HCV infection

-Serologic tests cannot predict or monitor response to antiviral therapy

 

See Hepatitis C: Testing Algorithm for Screening and Diagnosis in Special Instructions.

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.

Negative

Interpretation Provides information to assist in interpretation of the test results

A positive result indicates the presence of hepatitis C virus (HCV)-specific IgG antibodies due to past (resolved) or chronic hepatitis C. Past (resolved) HCV infection (accounting for about 25% of all HCV-infected patients) can be distinguished from chronic HCV infection (about 75% of all cases) only by direct detection of HCV RNA using molecular test methods; eg, HCVQN / Hepatitis C Virus (HCV) RNA Detection and Quantification by Real-Time Reverse Transcription-PCR (RT-PCR), Serum. HCV RNA is present in acute or chronic hepatitis C but not in past (resolved) HCV infection.

 

A negative result indicates the absence of HCV-specific IgG antibodies. A reactive HCV antibody screening test result with a negative HCV antibody confirmatory result indicates a probable false-reactive screening test result.

 

An indeterminate result indicates that HCV-specific IgG antibodies may or may not be present. Indeterminate results should be interpreted along with patient's risk factors for HCV infection and clinical findings. Individuals at risk for HCV infection with indeterminate results should be retested with an HCV antibody confirmatory test in 1 to 2 months to determine the definitive HCV antibody status. Molecular tests to detect HCV RNA may be necessary to determine HCV infection status in those at-risk immunocompromised patients with indeterminate HCV antibody confirmatory test results due to delayed appearance of fully complement of HCV-specific antibodies.

 

An unreadable result indicates nonspecific cross reactivity was present and HCV-specific antibody bands could not be visualized reliably. Repeat confirmatory serologic testing in 1 to 2 months or HCV RNA (HCVQN / Hepatitis C Virus [HCV] RNA Detection and Quantification by Real-Time Reverse Transcription-PCR [RT-PCR], Serum) is recommended for at-risk patients.

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

Performance characteristics have not been established for the following types of specimen:

-Cadaveric specimens

-Grossly hemolyzed (hemoglobin level of >100 mg/dL)

-Presence of particulate matter

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

1. American Association for the Study of Liver Diseases/Infectious Diseases Society of America/International Antiviral Society-USA. Recommendations for Testing, Managing, and Treating Hepatitis C. Accessed January 27, 2015. Available at www.hcvguidelines.org

2. Carithers RL, Marquardt A, Gretch DR: Diagnostic testing for hepatitis C. Semin Liver Dis 2000;20(2):159-171

3. Pawlotsky JM: Use and interpretation of hepatitis C virus diagnostic assays. Clin Liver Dis 2003;7:127-137

4. Centers for Disease Control and Prevention: Guidelines for laboratory testing and result reporting of antibody to hepatitis C virus. MMWR Morb Mortal Wkly Rep 2003;52(No. RR-3):1-14 Accessed April 2020. Available at www.cdc.gov/mmwr/preview/mmwrhtml/rr5203a1.htm

5. Centers for Disease Control and Prevention: Testing for HCV infection: an update of guidance for clinicians and laboratorians. MMWR Morb Mortal Wkly Rep 2013;62:362-365 Accessed April 2020. Available at www.cdc.gov/mmwr/preview/mmwrhtml/mm6218a5.htm?s_cid=mm6218a5_w

Special Instructions Library of PDFs including pertinent information and forms related to the test