National Health and Nutrition Examination Survey
Participant Involvement and Benefits
The National Health and Nutrition Examination Survey is a population-based survey designed to collect information on the health and nutrition of the U.S. household population. You may have come across data gathered through NHANES during your professional education. NHANES data have been used to influence policy and improve the health of the U.S. population in many ways including: getting lead removed from gasoline; creating and updating the pediatric growth charts; and establishing national baseline estimates for cholesterol, blood pressure, and Hepatitis C in the U.S.
There are two parts to this survey: the home interview and the health examination. We obtain written informed consent from each participant for both the in-home interview and the health exam. During the in-home interview participants are asked questions about health status, disease history, and diet. The health examination is performed in a mobile exam center (MEC). The MEC is made up of four trailers, linked sideways, containing high-tech medical equipment. During the health examination many tests are performed; however, no internal exams or invasive procedures are done. Some of these tests (e.g. digital images of the retina) are not normally performed at a physician’s office and could give the participant and his/her doctor additional information on his/her health. The examinations a participant will have depend on that participant’s age and gender.
For a list of examinations, see Health Exam Tests. Participants are informed that the NHANES health exam is not a substitute for their regular health care visits.
All participants receive a written Report Of Findings [PDF - 78 KB] approximately 12 weeks after the exam. If the survey program detects an abnormal value, the participant is notified immediately by letter.
For additional information on participant involvement and benefits please refer to the Participant Page.
Notification and Referral for Selected Infectious Diseases
The NHANES is conducted by the National Center for Health Statistics, which is part of the Centers for Disease Control and Prevention (CDC). The objective of the survey is to assess the health and nutritional status of adults and children in the United States. We gather and protect all information in keeping with the requirements of Federal Law. The Public Health Service Act (42 USC 242k) authorizes data collection. Section 308(d) of that law (42 USC 242 m) and the Privacy Act of 1974 (5 USC 552A) prohibit us from giving out information that identifies individuals in the survey without their consent.
Because the survey is for health research purposes only, our methods encompass procedures for measuring health status in the general population. These methods are not always similar to those used in clinical settings. Additionally, our survey physicians do not complete a history or physical exam on individual participants and therefore do not diagnose medical conditions. If a health problem is suspected based on findings from the survey protocol, participants are informed and referred to their local health care provider or health department clinic for evaluation and management. The legal obligation to report notifiable diseases to authorities will be fulfilled by the local provider or health department clinic if the participant’s clinical or laboratory assessment by the provider meets the case definition for infectious conditions under public health surveillance in their state.
The following is the survey protocol for notification and referral:
Participants are given STD/HIV test results by a health educator certified in HIV counseling by phone one month after their examination. Adults who do not call in receive up to 3 reminder letters. Teenagers are reminded by telephone. Participant identity is confirmed by a password. A participant with a positive test result based on the lab assays described below, is counseled and referred to his/her local doctor or health department STD clinic for repeat testing and evaluation. Upon request, a results letter is mailed to the participant: In addition to test results, laboratory assays used are reported in the letter as follows:
Explanation of the laboratory assays:
Chlamydia and gonorrhea
Urine is tested using a ligase chain reaction (LCR) test (Abbott) designed to detect the presence of DNA of chlamydia and/or gonorrhea.
Herpes Type 2
Blood is tested by type-specific immunodot assay developed and performed by scientists at the Emory University School of Medicine to detect andt-HSV-2 antibodies.
Blood is tested using an enzyme-linked immunoassay (ELISA) to detect antibody to HIV with a western blot confirmation of positive ELISA tests.
- High-risk types - A vaginal swab is tested using the Digene Hybridâ Capture II test to detect the presence of HPV types: 16/18/31/35/39/45/51/52/56/58/59/68.
- Low-risk types - A vaginal swab is tested using the Digene Hybridâ Capture II test to detect the presence of HPV types: 6/11/42/43/44.
National Center for Health Statistics
3311 Toledo Rd
Hyattsville, MD 20782-2064
1 (800) 232-4636
TTY: 1 (888) 232-6348
- Contact CDC–INFO