Hepatitis viruses constitute a major public health problem because of the morbidity and mortality associated with the acute and chronic consequences of these infections. New immunization strategies have been developed to eliminate the spread of hepatitis B virus (HBV) and hepatitis A virus (HAV) in the United States. Recommendations have also been developed for the prevention and control of hepatitis C virus (HCV) infection. Because of the high rate of asymptomatic infection with these viruses, information about the prevalence of these diseases is needed to monitor prevention efforts. By testing a nationally representative sample of the U.S. population, NHANES will provide the most reliable estimates of age-specific prevalence needed to evaluate the effectiveness of the strategies to prevent these infections. In addition, NHANES provides the means to better define the epidemiology of other hepatitis viruses. NHANES testing for markers of infection with hepatitis viruses will be used to determine secular trends in infection rates across most age and racial/ethnic groups, and will provide a national picture of the epidemiologic determinants of these infections.
All participants aged 6 years or older are eligible to be tested.
Serum specimens are processed, stored, and shipped to the Division of Viral Hepatitis, National Center for HIV/AIDS, Viral Hepatitis, STD, and TB Prevention, Centers for Disease Control and Prevention. Detailed instructions on specimen collection and processing can be found on the NHANES website.
Hepatitis C Antibody (anti-HCV)
The VITROS Anti-HCV assay is performed using the VITROS Anti-HCV Reagent Pack and VITROS Immunodiagnostic Products Anti-HCV Calibrator on the VITROS ECi/ECiQ or VITROS 3600 Immunodiagnostic System.
An immunometric technique is used. This involves a two-stage reaction. In the first stage, HCV antibody present in the sample binds with HCV recombinant antigens coated on the wells. Unbound sample is removed by washing. In the second stage, horseradish peroxidase (HRP)-labeled antibody conjugate (mouse monoclonal anti-human IgG) binds to any human IgG captured on the well in the first stage. Unbound conjugate is removed by washing.
A reagent containing luminogenic substrates (a luminol derivative and a peracid salt) and an electron transfer agent, is added to the wells. The HRP in the bound conjugate catalyzes the oxidation of the luminol derivative, producing light. The electron transfer agent increases the level and duration of the light produced. The light signals are read by the VITROS ECi/ECiQ or VITROS 3600 Immunodiagnostic System. The amount of HRP conjugate bound is indicative of the level of anti-HCV present in the sample.
Positive specimens are repeated in duplicate according to the same procedure. Repeatedly positive specimens are tested supplementally using the Chiron RIBA Processor System (Chiron Corporation, Inc.).
The Chiron RIBA HCV 3.0 Strip (confirmation test)
The Chiron RIBA 3.0 Strip Immunoblot Assay (SIA; Chiron Corporation, Inc.) is an in vitro qualitative enzyme immunoassay for the detection of anti-HCV in human serum or plasma.
Detection of anti-HCV by SIA methodology is based upon traditional Western and dot blotting techniques, in which specific immunogens (i.e. antigenic polyproteins) encoded by the HCV genome are immobilized onto a membrane support. Visualization of anti-HCV reactivity in specimens to the individual HCV-encoded proteins is accomplished with anti-human IgG enzyme-conjugates in conjunction with a colorimetric enzyme substrate. Samples with a positive RIBA result are reported as confirmed positive for antibody to HCV. Samples with a negative RIBA result are reported as negative for antibody to HCV and indeterminate RIBA results are reported as indeterminate.
Hepatitis C RNA (HCV-RNA)
The AMPLIPREP COBAS TaqMan HCV Test is an in vitro nucleic acid amplification test for the quantitation of Hepatitis C Virus RNA in human serum or plasma performed on the COBAS AMPLIPREP Instrument and the COBAS TaqMan 48 Analyzer.
Hepatitis C genotype
The VERSANT® HCV Genotype 2.0 Assay (LiPA) is a line probe assay designed to identify Hepatitis C virus (HCV) genotypes 1 to 6 in human serum or EDTA plasma samples. Subtype information is available in the majority of cases.
There were no changes (from the previous 2 years of NHANES) to equipment, lab methods, or lab site for anti-HCV, RIBA or genotype testing. The AMPLIPREP COBAS TaqMan HCV Test replaced the COBAS AMPLICOR HCV Test for HCV RNA testing.
The analytical methods are described in the Description of Laboratory Methodology section above.
The NHANES quality control and quality assurance protocols (QA/QC) meet the 1988 Clinical Laboratory Improvement Act mandates. Detailed QA/QC instructions are discussed in the NHANES Laboratory/Medical Technologists Procedures Manual (LPM).
Refer to the 2011-2012 Laboratory Data Overview for general information on NHANES laboratory data.
The analysis of NHANES 2011-2012 laboratory data must be conducted using the appropriate survey design and demographic variables. The NHANES 2011-2012 Demographics File contains demographic data, health indicators, and other related information collected during household interviews as well as the sample weight variables. The Fasting Questionnaire File includes auxiliary information such as fasting status, the time of venipuncture, and the conditions precluding venipuncture. The demographics and fasting questionnaire files may be linked to the laboratory data file using the unique survey participant identifier (i.e., SEQN).
The age range and constraints for hepatitis C testing are as follows:
The screening hepatitis C antibody test is performed on all examinees 6 years old or older. Samples testing positive for anti-HCV by the screening test were tested in the confirmatory RIBA assay for antibody to hepatitis C virus. Samples with a positive RIBA result are reported as confirmed positive for antibody to HCV. Samples with a negative RIBA result are reported as negative for antibody to HCV. Samples with an indeterminate RIBA result are reported out as such and subsequently tested for HCV RNA to confirm the infection status of the patient. Samples that tested negative for anti-HCV by the screening test were not tested by RIBA. These samples were reported as negative for antibody to HCV. Samples that tested positive or indeterminate for HCV RNA were subsequently tested for HCV genotype.
Exam sample weights should be used for analyses. Please refer to the NHANES Analytic Guidelines and the on-line NHANES Tutorial for further details on the use of sample weights and other analytic issues.
| Code or Value | Value Description | Count | Cumulative | Skip to Item |
|---|---|---|---|---|
| 1 | Positive | 93 | 93 | |
| 2 | Negative | 6952 | 7045 | |
| 5 | Indeterminate | 19 | 7064 | |
| . | Missing | 757 | 7821 |
| Code or Value | Value Description | Count | Cumulative | Skip to Item |
|---|---|---|---|---|
| 1 | Positive | 64 | 64 | |
| 2 | Negative | 33 | 97 | |
| . | Missing | 7724 | 7821 |
| Code or Value | Value Description | Count | Cumulative | Skip to Item |
|---|---|---|---|---|
| 1 | Genotype 1a | 42 | 42 | |
| 2 | Genotype 1b | 14 | 56 | |
| 3 | Genotype 1 other than 1a/1b/or with subtype not determined | 0 | 56 | |
| 4 | Genotype 2 | 4 | 60 | |
| 5 | Genotype 3 | 2 | 62 | |
| 6 | Genotype 4 | 0 | 62 | |
| 7 | Genotype 5 | 0 | 62 | |
| 8 | Genotype 6 | 0 | 62 | |
| 9 | Genotype undetermined | 1 | 63 | |
| . | Missing | 7758 | 7821 |