National Health and Nutrition Examination Survey

2007 - 2008 Data Documentation, Codebook, and Frequencies

Hepatitis B: core antibody, surface antigen, and Hepatitis D antibody (HEPBD_E)

Data File: HEPBD_E.xpt

First Published: September, 2009

Last Revised: NA

Locator Record

Title: Hepatitis B: core antibody, surface antigen, and Hepatitis D antibody (HEPBD_E )
Contact Number: 1-866-441-NCHS
Years of Content: 2007 - 2008
First Published: September, 2009
Revised: NA
Access Constraints: None
Use Constraints: None
Geographic Coverage: National
Subject: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.
Record Source: NHANES 2007 - 2008
Survey Methodology: NHANES 2007 - 2008 is a stratified multistage probability sample of the civilian non-institutionalized population of the U.S.
Medium: NHANES Web site; SAS transport files

Component Description

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.

Eligible Sample

All participants aged 6 years and older are eligible to be tested.

Description of Laboratory Methodology

Blood specimens are processed, stored, and shipped to the Division of Viral Hepatitis, National Center for Infectious Diseases, National Centers for Disease Control and Prevention. Detailed specimen collection and processing instructions are discussed in the NHANES Laboratory/Medical Technologists Procedures Manual (LPM.)

Hepatitis B core antibody

The Ortho HBc ELISA Test System is a qualitative enzyme-linked immunosorbent assay (ELISA) for the detection of total antibody to anti-HBc in human serum or plasma. Anti-HBc appears in virtually all individuals infected with HBV and is an accurate serological marker of current and past infection.

ELISA procedures provide a means for routinely detecting antibodies to specific antigens. This FDA-licensed method is commercially obtained in kit form. The literature and instructions with each kit constitute the standard operating procedure (SOP) for the method.

Hepatitis B surface antigen

The AUSZYME Monoclonal test is a solid-phase “sandwich” enzyme immunoassay used to detect the presence of HBsAg, which indicates current infection with HBV. Specimens that test nonreactive by the AUSZYME Monoclonal tests (Abbott Diagnostics) are considered negative for HBsAg and are not tested further. All specimens considered reactive initially are repeat-tested in duplicate using the same procedure as that used in the initial test. If neither of the repeat tests is reactive, the specimen is considered negative for HBsAg. If the specimen is reactive in either of the repeat tests, the sample is considered repeatedly reactive.

Hepatitis D antibody

The International Immunodiagnostics HDV Ab assay is a competitive enzyme immunoassay (ELISA) for the determination of antibodies to Hepatitis D Virus or HDV in human plasma and sera with a 'two step” methodology. Anti-HDV antibodies, if present in the sample, compete with a virus specific polyclonal IgG, labeled with peroxidase (HRP), for a fixed amount of rec-HDV coated on the Microplate, in” two step" incubation. The concentration of the bound enzyme on the solid phase is inversely proportional to the amount of anti-HDV antibodies in the sample and its activity is detected by adding the chromagen/substrate in the second incubation. The concentration of HDV-specific antibodies in the sample is determined by means of a cut-off value that allows for the semi-quantitative detection of anti-HDV antibodies.

There were no changes (from the previous 2 years of NHANES) to equipment, lab methods or lab site.

Data Processing and Editing

Read the General Documentation of Laboratory Data file for detailed data processing and editing protocols. The analytical methods are described in the Analytic Notes for Data Users section below.

Laboratory Quality Assurance and Monitoring

The NHANES quality assurance and quality control (QA/QC) protocols meet the 1988 Clinical Laboratory Improvement Act mandates. Detailed quality control and quality assurance instructions are discussed in the NHANES Laboratory/Medical Technologists Procedures Manual (LPM). Read the General Documentation of Laboratory Data file for detailed QA/QC protocols. A detailed description of the quality assurance and quality control procedures can be found on the NHANES website.

Analytic Notes

The analysis of NHANES laboratory data must be conducted with the key survey design and basic demographic variables. The NHANES Household Questionnaire Data Files contain demographic data, health indicators, and other related information collected during household interviews. They also contain all survey design variables and sample weights for these age groups. The phlebotomy file includes auxiliary information such as the conditions precluding venipuncture. The household questionnaire and phlebotomy files may be linked to the laboratory data file using the unique survey participant identifier SEQN.

The age range and constraints for hepatitis testing are as follows:

Hep B

The hepatitis B core antibody test is performed on all examinees 6 years old and older while the hepatitis B surface antibody test is performed on all examinees 2 years old and older. The surface antigen is tested only when the core antibody test is positive. Participant results are coded positive for surface antigen if the surface antigen test is positive; they are coded negative for surface antigen if the test for surface antigen is negative or if the test for hepatitis B core antibody is negative.

Hep  D

The Hepatitis Delta Virus (HDV) is a RNA defective virus and infection with HDV only occurs in the presence of acute or chronic HBV infection. In NHANES, the test for antibody to HDV is performed on participants 6 years of age or older who test positive for antiHBc and HBsAg. The denominator for antiHDV has been derived to include all anti-HBc negative samples, the anti-HBc positive samples that were subsequently found to be HBsAg negative, and the samples that were anti-HBC positive and HBsAg positive that were subsequently found to be antiHDV negative.

Exam sample weights should be used for analyses. Please refer to the Analytic Guidelines for further details on the use of sample weights and other analytic issues. The Analytic Guidelines are available on the NHANES website

References

N/A.

Codebook and Frequencies