Helicobacter pylori has been shown to be the causative agent in chronic-active gastritis, and evidence has almost completely satisfied Koch's postulates for this organisms' pathogenicity in primary duodenal ulcers. More recent evidence has suggested that chronic H. pylori infection as well as early age of H. pylori-acquisition is a critical precursor to gastric carcinoma. Questions must be addressed in a carefully considered manner that combines systematic, demographic epidemiology with the knowledge of H. pylori positivity or negativity. Furthermore, at-risk cohorts should be particularly examined to address unresolved controversies regarding route of transmission, environmental risk factors (i.e., food or water), inheritability or familial tendencies for infection susceptibility, factors leading to carcinogenesis, the demographics of susceptibility in very young children, and possible growth disturbances caused by H. pylori infection. Because NHANES will have numerous data on environmental exposures, these data was analyzed to add information on potential route of transmission for this organism.
Participants aged 3 and above years were tested.
The Wampole Laboratories (Wampole) H. pylori IgG Enzyme-Linked Immunosorbent Assays (ELISA) is intended for the detection and qualitative determination of IgG antibodies to Helicobacter pylori in human serum. This assay is intended for use as an aid in the diagnosis of H. pylori infection in persons with gastrointestinal symptoms. For in vitro diagnostic use only.
Enzyme linked immunosorbent assays (ELISA) rely on the ability of biological materials, (i.e. antigens) to adsorb to plastic surfaces such as polystyrene (solid phase). When antigens bound to the solid phase are brought into contact with a participant's serum, antigen-specific antibody, if present, will bind to the antigen on the solid phase forming antigen-antibody complexes. Excess antibody is removed by washing. This is followed by the addition of goat anti-human IgG conjugated with horseradish peroxidase, which then binds to the antibody-antigen complexes. The excess conjugate is removed by washing, followed by the addition of chromogen substrate tetramethylbenzidine (TMB). If specific antibody to the antigen is present in the participant's serum, a blue color developed. When the enzymatic reaction is stopped with 1N H2SO4, the contents of the wells turn yellow. The color, which is proportional to the concentration of antibody in the serum, is read on a suitable spectrophotometer or ELISA microwell plate reader. The sensitivity, specificity, and reproducibility of enzyme-linked immunoassays are comparable to other serological tests for antibody, such as immunofluorescence, complement fixation, hemagglutination, and radioimmunoassays.
Specimens were processed, stored and shipped to University of Washington, Seattle, Washington. Detailed specimen collection and processing instructions are discussed in the NHANES Laboratory/Medical Technologists Procedures Manual (LPM). Read the LABDOC file for detailed data processing and editing protocols. The analytical methods are described in the Description of the Laboratory Methodology section.
The NHANES quality control and quality assurance protocols (QA/QC) 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.
The analysis of NHANES 2001 laboratory data must be conducted with the key survey design and basic demographic variables. The NHANES 2001 Household Questionnaire Data Files contain demographic data, health indicators, and other related information collected during household interviews. 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.
A value <0.90 is considered negative for the presence of detectable IgG antibody. Values between 0.91-1.09 are considered equivocal and values greater than 1.10 indicates the presence of detectable IgG antibody.
The variable names and variable descriptors are as follows:
SEQN Sequence number
LB2HP1 Helicobacter pylori result
WTMEC1YR Full sample 1 year MEC weight
| Code or Value | Value Description | Count | Cumulative | Skip to Item |
|---|---|---|---|---|
| 0.01 to 4.5 | Range of Values | 4296 | 4296 | |
| . | Missing | 398 | 4694 |
| Code or Value | Value Description | Count | Cumulative | Skip to Item |
|---|---|---|---|---|
| 3718.159075 to 383168.555251 | Range of Values | 4694 | 4694 | |
| . | Missing | 0 | 4694 |