• Component Description
• Eligible Sample
• Description of Laboratory Methodology
• Laboratory Quality Assurance and Monitoring
• Data Processing and Editing
• Analytic Notes
• Codebook
  • SEQN - Respondent sequence number
  • WTANA6YR - ANA Subsample 6 year Weight
  • SSDFSS - Dense fine speckled signal
  • SSDFSE - Dense fine speckled EIS unit
  • SSDFSR - Dense fine speckled result

National Health and Nutrition Examination Survey

1999-2004 Data Documentation, Codebook, and Frequencies

Autoantibodies - Anti-DFS70 Autoantibody Analyses (Surplus) (SSDFS_A)

Data File: SSDFS_A.xpt

First Published: July 2022

Last Revised: NA

Component Description

IgG autoantibody testing of a subsample of stored serum from 1999-2004 participants was conducted to estimate the prevalence and specificities of selected autoantibodies in the US population.

Eligible Sample

A one third subsample of participants aged 12 years and older from 1999-2004 who were examined, had available surplus sera, and with specific laboratory findings based on prior testing (tested positive for HEp-2 indirect immunofluorescence assay (IFA) with dense fine speckled pattern (AC-2)) were eligible for inclusion (see: https://wwwn.cdc.gov/Nchs/Nhanes/1999-2000/SSANA2_A.htm).

Description of Laboratory Methodology

Anti-DFS70 autoantibody determination using enzyme-linked immunosorbent assay (ELISA)
testing of IgG autoantibodies to human DFS70 antigen was performed by a DFS70 ELISA kit from Medical & Biological Laboratories Co., LTD (7808, Japan) as per manufacturer’s instructions. 

Laboratory Quality Assurance and Monitoring

ELISA analysis
Serum samples previously tested positive in HEp-2 indirect immunofluorescence assay (IFA) with nuclear dense fine speckled pattern (AC-2) were selected for anti-DFS70 autoantibody ELISA analyses. Established protocols were completed as outlined by the manufacturer with a positive-negative cutoff as recommended at 15 unit/mL. (i.e. 15 or under = negative).

Samples were analyzed in duplicates and values represent averaged data. Samples that showed discrepant results were repeated. Repeats were performed whenever there was any doubt for accuracy or technical issues.

Data Processing and Editing

Data Access: All data are publicly available.

Analytic Notes

The NHANES Survey Design:

The analysis of NHANES laboratory data should be conducted using the key survey design variables. The NHANES Demographic data files for each 2-year survey cycle contain core information on the survey participant including: variables for interview and examination status; demographic variables including age, gender, race/ethnicity; NHANES interview and examination sample weight variables and the survey design variables for strata and PSU (SDMVSTRA and SDMVPSU, respectively) which are recommended to be used in variance estimation.

The NHANES Questionnaire data files contain socio-economic data, health indicators, and other related information collected during household interviews. The Phlebotomy examination data file includes auxiliary information on duration of fasting, the time of day of the venipuncture, and the conditions precluding venipuncture. The demographic, questionnaire and phlebotomy examination files may be linked to the laboratory data file using the unique survey participant identifier SEQN. Autoantibody immunofluorescence and immunoprecipitation (ANA) data were obtained from a total of five NHANES cycles (NHANES III (phase 1, 1988-1991), 1999-2000, 2001-2002, 2003-2004, and 2011-2012 cohorts).

Weighting:

Subsample weights are required to analyze these data properly. Special subsample sample weights are included in this file, WTANA6YR. This file is intended to be used in conjunction with the SSANA_A and SSANA2_A files. 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.

Codebook and Frequencies