Table of Contents

Component Description

Testing of stored sera specimens from NHANES 2015-16 was conducted to examine the distribution of immunoglobulin G (IgG) levels against four Bordetella pertussis antigens (pertussis toxin [PT], filamentous hemagglutinin [FHA], pertactin [PRN] and fimbria types 2 and 3 [FIM]) to determine population-based antibody levels. Testing was also conducted to evaluate antibody levels to tetanus toxin (TT).

Pertussis: Although no immunologic correlates of protection have yet been identified for pertussis, IgG antibody levels against four virulence factors (pertussis toxin (PT), fimbriae (FIM), filamentous hemagglutinin (FHA), and pertactin (PRN)) are used to assess immunogenicity following vaccination and disease (Mattoo, et al., 2005).

Tetanus: Data on minimum anti-tetanus antibody cut-off level for protection are sparse. Antibodies levels ≥0.01 IU/mL as measured by in vivo toxin neutralization assays are generally considered protective (Borrow, et al., 2007).

Eligible Sample

Participants aged 6 years and over, who gave consent for their samples to be used in future research and had stored samples from 2015-2016, were eligible.

Description of Laboratory Methodology

Microsphere-based multiplex antibody capture assay (MMACA): This assay tested antibodies to tetanus toxin (TT) and four Bordatella pertussis antigens (PT, FIM, FHA, PRN). MMACA quantifies antibodies to multiple antigens in a single reaction, using extremely low amount of capture antigen and sample volume (Rajam, et. al., 2019). The MMACA is a highly sensitive, specific, accurate, precise, and rapid test. Diluted serum specimens are incubated with antigen-conjugated fluorescent beads. After a series of washes, antibody bound to the antigens on the beads are detected with phycoerythrin (PE) labeled species-specific secondary-reporter antibody. The XMap technology platform is used to populate the antigen conjugated beads and simultaneously detect the PE reporter. The MMACA is calibrated to the WHO International Standard 06/140 for pertussis antibodies and TE-3 for TT antibodies. The reportable value (RV) of the assay is expressed as the serum concentration of anti-pertussis or TT antigen-specific IgG in IU/mL. The assay RV was calculated from a program developed by CDC that operates from the SAS system, version 9.0 or higher (SAS Institute, Cary, NC).  

Laboratory Quality Assurance and Monitoring

This laboratory assay was performed in the Microbial Pathogenesis and Immune Response Laboratory, Division of Bacterial Diseases, National Center for Immunization and Respiratory Diseases, Centers for Disease Control and Prevention, Atlanta, GA for analysis.

The following quality control criteria are applied to every run:

Reference Standard: R2 of the 4-PL curve fit must be ≥0.98 for each antigen, if it is <0.98 that antigen is repeated for all samples on the plate.

Positive Control: Calculated concentration must be within 2 standard deviations of the pre-established mean for each antigen. If it is outside the +/- 2SD range, the antigen is repeated for all samples on the plate. The long-term CV of the assay is 25%.

Negative Control: Raw signal must be ≤30 MFI units for each antigen. If it is >30MFI, the antigen is repeated for all samples on the plate.

Unknown Specimens: The CV of the concentration calculated from multiple dilutions must be <30% for each antigen. There must be at least 3 dilutions in the useable range unless all unused dilutions are below the limit of detection (allowing low samples only to pass with <3 dilutions). High concentration samples are repeated at a higher starting dilution, high CV samples are repeated at the same starting dilution.

Data Processing and Editing

Data was compiled into a database after all the assays were completed and passed quality control criteria. The data were not edited.

Analytic Notes

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.

Special Weights

Sample weights are required to analyze these data properly. Special sample weights for this sample are included in this data file and should be used when analyzing these data (WTSSPT).

Demographic and Other Related Variables

The analysis of NHANES laboratory data must be conducted using the appropriate survey design and demographic variables. The NHANES 2015-2016 Demographics File contains demographic data, health indicators, and other related information collected during household interviews as well as the sample design variables. The recommended procedure for variance estimation requires use of stratum and PSU variables (SDMVSTRA and SDMVPSU, respectively) in the demographic data file.

This laboratory data file can be linked to the other NHANES data files using the unique survey participant identifier (i.e., SEQN).

Detection Limits

Two variables are provided for each of these analytes. The variable name ending in “L” (ex., SSFHAL) indicates whether the result was below the lower limit of quantitation (LLOQ): the value “0” means that the result was at or above the LLOQ, “1” indicates that the result was below the LLOQ.  The other variable (ex., SSFHA) provides the analytic result for that analyte.  Uncensored analytic results were provided regardless of whether they were above, at, or below the LLOQ.

The lower limit of quantitation (LLOQ in IU/ml):

Variable Name

English Text

Lower Limit of Quantitation (LLOQ) (IU/ml)

SSFHA

Pertussis Filamentous hemagglutinin antibody IU/mL

0.15

SSFIM

Pertussis Fimbriae antibody IU/mL

0.06

SSPT

Pertussis toxin antibody IU/mL

0.08

SSPRN

Pertactin antibody IU/mL

0.04

SSTT

Tetanus toxin antibody IU/mL

0.007

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 6 YEARS - 150 YEARS

SSFHA - Pertussis Filamentous hemagglutinin ab

Variable Name:
SSFHA
SAS Label:
Pertussis Filamentous hemagglutinin ab
English Text:
Pertussis Filamentous hemagglutinin antibody IU/mL
Target:
Both males and females 6 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0.19 to 3549.45 Range of Values 5911 5911
. Missing 0 5911

SSFHAL - Pertussis Filamentous hemag ab cmt code

Variable Name:
SSFHAL
SAS Label:
Pertussis Filamentous hemag ab cmt code
English Text:
Pertussis Filamentous hemag ab comment code
Target:
Both males and females 6 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0 At or above LLOQ 5911 5911
1 Below LLOQ 0 5911
. Missing 0 5911

SSFIM - Pertussis Fimbriae antibody IU/mL

Variable Name:
SSFIM
SAS Label:
Pertussis Fimbriae antibody IU/mL
English Text:
Pertussis Fimbriae antibody IU/mL
Target:
Both males and females 6 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0.03 to 5201.99 Range of Values 5903 5903
. Missing 8 5911

SSFIML - Pertussis Fimbriae antibody comment code

Variable Name:
SSFIML
SAS Label:
Pertussis Fimbriae antibody comment code
English Text:
Pertussis Fimbriae antibody comment code
Target:
Both males and females 6 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0 At or above LLOQ 5896 5896
1 Below LLOQ 7 5903
. Missing 8 5911

SSPT - Pertussis toxin antibody IU/mL

Variable Name:
SSPT
SAS Label:
Pertussis toxin antibody IU/mL
English Text:
Pertussis toxin antibody IU/mL
Target:
Both males and females 6 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0.02 to 1454.71 Range of Values 5902 5902
. Missing 9 5911

SSPTL - Pertussis toxin antibody comment code

Variable Name:
SSPTL
SAS Label:
Pertussis toxin antibody comment code
English Text:
Pertussis toxin antibody comment code
Target:
Both males and females 6 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0 At or above LLOQ 5901 5901
1 Below LLOQ 1 5902
. Missing 9 5911

SSPRN - Pertactin antibody IU/mL

Variable Name:
SSPRN
SAS Label:
Pertactin antibody IU/mL
English Text:
Pertactin antibody IU/mL
Target:
Both males and females 6 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0.06 to 20144.94 Range of Values 5911 5911
. Missing 0 5911

SSPRNL - Pertactin antibody comment code

Variable Name:
SSPRNL
SAS Label:
Pertactin antibody comment code
English Text:
Pertactin antibody comment code
Target:
Both males and females 6 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0 At or above LLOQ 5911 5911
1 Below LLOQ 0 5911
. Missing 0 5911

SSTT - Tetanus toxin antibody IU/mL

Variable Name:
SSTT
SAS Label:
Tetanus toxin antibody IU/mL
English Text:
Tetanus toxin antibody IU/mL
Target:
Both males and females 6 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0.001 to 146.297 Range of Values 5910 5910
. Missing 1 5911

SSTTL - Tetanus toxin antibody comment code

Variable Name:
SSTTL
SAS Label:
Tetanus toxin antibody comment code
English Text:
Tetanus toxin antibody comment code
Target:
Both males and females 6 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0 At or above LLOQ 5823 5823
1 Below LLOQ 87 5910
. Missing 1 5911

WTSSPT - Adjusted examination weight

Variable Name:
WTSSPT
SAS Label:
Adjusted examination weight
English Text:
Adjusted examination weight
Target:
Both males and females 6 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
6109.60849 to 268739.96713 Range of Values 5911 5911
. Missing 0 5911