Table of Contents

Component Description

Among adults aged 20-64 years, randomly selected, who participated in NHANES between 2005 and 2006 and had stored serum samples available, Salmonella and Campylobacter antibody testing was conducted. IgG, IgA and IgM antibodies were measured using enzyme immunoassays.

Eligible Sample

Surplus sera from adults aged 20-64 years who participated in NHANES years 2005 to 2006.

Description of Laboratory Methodology

25μL of sample is required for each assay. Specimens, calibrators and controls are pre-diluted 1:200 prior to placing them in the test wells. Cut-off calibrator, controls and subject samples are diluted in PBS with 1% Bovine serum albumin, mixed briefly by vortex to assure good distribution of the sample in the diluent, and then transferred to the test plate by a Biomek NXP robot prior to incubation. After washing the wells, conjugate is added with another incubation and wash step following. Substrate is added and allowed to incubate before the addition of stop/color reagent. The plates are read at an absorbance of 405 nm using a reference wavelength of 540 nm.

Data Processing and Editing

Data were submitted after all the antibody testing was complete. The data were not edited.

Data Access: All data will be publicly available. 

Laboratory Quality Assurance and Monitoring

Commercial alkaline phosphatase conjugates were used for the anti IgA and IgM antibody testing. CDC produced monoclonal antibody HP 6043 with a alkaline phosphastase conjugate was used for anti IgG antibody detection. All QA/QC procedures recommended by the manufacturer were followed. NHANES serum was tested in quadruplicate, and accepted if the standard deviation was less than 0.200. Serum results with a high standard deviation were retested if after a outlying value was excluded, the standard deviation was still over 0.200.

Analytic Notes

The EIA indices have yet to be determined. Preliminary laboratory evaluations using the MedCalc™ ROC curve analysis software has been performed. The indices are considered to be tentative pending a formal evaluation by Enteric Diseases Epidemiology Branch statisticians.
Salmonella IgA positive value: .323
Salmonella IgG positive value: .446
Salmonella IgM positive value: .222
Campylobacter IgA positive value: .481
Campylobacter IgG positive value: .229
Campylobacter IgM positive value: .375
Analysis and mathematical modeling of the NHANES serum results are awaiting the final statistical analysis of the validation data.

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 20 YEARS - 64 YEARS

SSSalIgA - Salmonella IgA

Variable Name:
SSSalIgA
SAS Label:
Salmonella IgA
English Text:
Salmonella IgA
Target:
Both males and females 20 YEARS - 64 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0 to 2.471 Range of Values 1172 1172
. Missing 14 1186

SSSalIgG - Salmonella IgG

Variable Name:
SSSalIgG
SAS Label:
Salmonella IgG
English Text:
Salmonella IgG
Target:
Both males and females 20 YEARS - 64 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0 to 2.212 Range of Values 1173 1173
. Missing 13 1186

SSSalIgM - Salmonella IgM

Variable Name:
SSSalIgM
SAS Label:
Salmonella IgM
English Text:
Salmonella IgM
Target:
Both males and females 20 YEARS - 64 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0 to 1.681 Range of Values 1178 1178
. Missing 8 1186

SSCamIgA - Campylobacter IgA

Variable Name:
SSCamIgA
SAS Label:
Campylobacter IgA
English Text:
Campylobacter IgA
Target:
Both males and females 20 YEARS - 64 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0 to 2.796 Range of Values 1170 1170
. Missing 16 1186

SSCamIgG - Campylobacter IgG

Variable Name:
SSCamIgG
SAS Label:
Campylobacter IgG
English Text:
Campylobacter IgG
Target:
Both males and females 20 YEARS - 64 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0 to 3.632 Range of Values 1170 1170
. Missing 16 1186

SSCamIgM - Campylobacter IgM

Variable Name:
SSCamIgM
SAS Label:
Campylobacter IgM
English Text:
Campylobacter IgM
Target:
Both males and females 20 YEARS - 64 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0 to 1.992 Range of Values 1170 1170
. Missing 16 1186