• Component Description
• Eligible Sample
• Description of Laboratory Methodology
• Laboratory Quality Assurance and Monitoring
• Data Processing and Editing
• Analytic Notes
• References
• Codebook
  • SEQN - Respondent sequence number
  • SSFHA - Pertussis Filamentous hemagglutinin ab
  • SSFHAL - Pertussis Filamentous hemag ab cmt code
  • SSFIM - Pertussis Fimbriae antibody IU/mL
  • SSFIML - Pertussis Fimbriae antibody comment code
  • SSPT - Pertussis toxin antibody IU/mL
  • SSPTL - Pertussis toxin antibody comment code
  • SSPRN - Pertactin antibody IU/mL
  • SSPRNL - Pertactin antibody comment code
  • SSTT - Tetanus toxin antibody IU/mL
  • SSTTL - Tetanus toxin antibody comment code
  • WTSSPT - Adjusted examination weight

National Health and Nutrition Examination Survey

2015-2016 Data Documentation, Codebook, and Frequencies

Pertussis and tetanus – Serum (Surplus) (SSPT_I)

Data File: SSPT_I.xpt

First Published: June 2022

Last Revised: NA

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

• Borrow R, Balmer P & Roper MH (2007) World Health Organization The Immunological Basis for Immunization Series Module 3: Tetanus (Revision), p 1-52.
• Mattoo S, Cherry JD. Molecular pathogenesis, epidemiology, and clinical manifestations of respiratory infections due to Bordetella pertussis and other Bordetella subspecies. Clinical microbiology reviews. 2005;18(2):326-382.
• Rajam G, Carlone G, Kim E, et al. Development and validation of a robust multiplex serological assay to quantify antibodies specific to pertussis antigens. Biologicals. 2019 Jan;57:9-20.

Codebook and Frequencies