National Health and Nutrition Examination Survey

DNA Specimens and Genetic Data Program

DNA samples were collected in the National Health and Nutrition Examination Survey (NHANES) III (1988-1994) and in subsequent NHANES cycles  (1999-2002, 2007-2008, 2009-2010, and 2011-2012). The program is a nationally representative collection of stored DNA samples and genetic data and will serve to add to the extensive amount of health, nutritional, and environmental information collected from NHANES.

Laboratory Methodology


DNA was extracted from crude lysates of cell lines created from blood of participants aged 12 years and over. For NHANES III Phase II (1991-1994), DNA concentrations per sample vary and are estimated to range from 7.5-65 nanograms of DNA per microliter with an average of approximately four micrograms of DNA in 100 µl.

NHANES 1999-2002, 2007-2012

DNA was purified from whole blood of participants aged 20 years and over. Aliquots of purified DNA were normalized to concentrations of approximately 50 nanograms of DNA per microliter.

DNA specimen by cycle
Cycle Age (years) DNA Source N
NHANES III Phase II 12+ crude cell lysates 7,159
1999-2002 20+ whole blood 7,839
2007-2008 20+ whole blood 4,612
2009-2010 20+ whole blood 4,893
2011-2012 20+ whole blood 4,147


Genetic Data Repository

Resulting genetic variants are deposited into the NHANES Genetic Data Repository after NCHS Quality Control Review. Most of the datasets will be found in the category of restricted datasets although there are a small number of anonymized datasets.

Restricted Datasets

For information about NHANES genetic datasets and weights review the Genetic Data Repository Information Sheet [PDF – 35 KB] and Weights Documentation [PDF – 35 KB].

Accessing the list of genetic variants is available via the NHANES Genetic Variant Search. For written instructions and additional information review the Genetic Variant Search Information Sheet [PDF-29 KB].

Questions: Email

Anonymized Genetic Datasets

A limited number of associated variants have been anonymized so the data can no longer be linked to the public use files and therefore not linkable to other NHANES data. Data available upon request with a data use agreement. List of anonymized datasets [PDF-63 KB]. Contact for more information.

Quality Control Review

Only variants that pass NCHS Quality Control Review are added to the Genetic Data Repository. Documentation of NCHS Quality Control Review procedures: For candidate gene studies [PDF-82 KB]


Proposal Guidelines

DNA Samples

DNA samples are available for NHANES III, 1999-2002, 2007-08, 2009-10, and 2011-12.

For additional information and proposal guidelines, please see the Federal Register.

Access the Genetic Data Repository

Proposals to analyze genetic datasets may be submitted to the Research Data Center (RDC). For additional information on submission guidelines, please go to the RDC website. Contact for more information.


Publications Using DNA Specimens and/or Genetic Data Repository

A list of publications resulting from collected DNA samples and/or genetic data repository.

Frequently Asked Questions

What kind of studies can I do with the NHANES DNA samples?

NHANES is a nationally representative study and DNA samples are best utilized to determine associations with diseases or conditions using the survey sample weights. Case-control studies are discouraged.

What are the proposal guidelines for accessing the Genetic Data Repository?

See the RDC website for the proposal process.

Page last reviewed: July 18, 2022