Table of Contents

Locator Record

Title: Hepatitis A (HEPA_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:The Hepatitis A assay used in this study can not differentiate between natural infection and vaccination. Therefore seropositivity for anti-HAV reflects either natural or vaccine induced immunity.
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

Survey participants aged 2 to 19 years 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).

The VITROS Anti-HAV Total assay is performed using the VITROS Immunodiagnostic Products Anti-HAV Total Reagent Pack and the VITROS Immunodiagnostic Products Anti-HAV Total Calibrator on the VITROS ECi/ECiQ Immunodiagnostic System.

A competitive immunoassay technique is used which involves pre-incubation of anti-HAV in the sample with HAV antigen in the assay reagent, followed by incubation with a conjugate reagent that contains biotinylated mouse monoclonal anti-HAV antibody and horseradish peroxidase (HRP)-labeled mouse monoclonal anti-HAV antibody. The immune complex is captured by streptavidin on the wells. Unbound materials are removed by washing.

The bound HRP conjugate is measured by a luminescent reaction. 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 (a substituted acetanilide) increases the level of light produced and prolongs its emission. The light signals are read by the VITROS ECi/ECiQ Immunodiagnostic System. The binding of HRP is indicative of the absence of anti-HAV antibody.

There have been changes (from the previous 2 years of NHANES) to instruments and lab methods.

 

Data Processing and Editing

Read the General Documentation on Laboratory Data file for detailed data processing and editing protocols. The analytical methods are described in the Analytic Notes for Data Users section below. Detailed instructions on specimen collection and processing can be found on the NHANES website.

The age range changed from 2005-2006. In 2005-2006 all participants aged 2 and older were eligible for the test. In 2007-2008 participants aged 2 to 19 years were eligible for the test.

 

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 LABDOC 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 ranges and constraints for hepatitis testing are as follows:
The hepatitis A antibody test is performed on all participants aged 2 to 19 years.

The assay used can not differentiate between natural infection and vaccination. Therefore seropositivity for anti-HAV reflects either natural or vaccine induced immunity.

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

Codebook and Frequencies

SEQN - Respondent sequence number

Variable Name:
SEQN
SAS Label:
Respondent sequence number
English Text:
Respondent sequence number.
Target:
Both males and females 2 YEARS - 19 YEARS

LBXHA - Hepatitis A Antibody (Anti-HAV)

Variable Name:
LBXHA
SAS Label:
Hepatitis A Antibody (Anti-HAV)
English Text:
Hepatitis A Antibody (Anti-HAV)
Target:
Both males and females 2 YEARS - 19 YEARS
Code or Value Value Description Count Cumulative Skip to Item
1 Positive 1202 1202
2 Negative 1419 2621
3 Indeterminate 1 2622
. Missing 684 3306