Component Description
Accurate measurement of blood pressure (BP) is a major public health concern; it is essential for hypertension screening, as well as for disease management. This section provides data for three consecutive blood pressure (BP) measurements and other methodological measurements to obtain an accurate blood pressure.
Eligible Sample
Heart rate is measured on all children 0-7 years of age; radial pulse is measured on examinees 8 years and older; and blood pressure (BP) is measured on all examinees 8 years and older. Participants with any of the following on both arms were excluded from the exam: rashes, gauze dressings, casts, edema, paralysis, tubes, open sores or wounds, withered arms, a-v shunts, radical mastectomy or if BP cuff does not fit on the arm.
Protocol and Procedure
After resting quietly in a sitting position for 5 minutes and determining the maximum inflation level (MIL), three consecutive blood pressure readings are obtained. If a blood pressure measurement is interrupted or incomplete, a fourth attempt may be made. All BP determinations (systolic and diastolic) are taken in the mobile examination center (MEC).
Quality Assurance & Quality Control
The BP examiners are certified for blood pressure measurement through a training program from Shared Care Research and Education Consulting. Certification is achieved when physician examiners meet all requirements of the training program. The initial training includes:
- didactic instruction about BP measurement and propensity for error;
- practice listening to systolic and diastolic BP sounds using a standardized audio-video tape presentation;
- audio-video tape test;
- written exam;
- examiner and gold standard instructor simultaneously listening to BP of a minimum of 20 volunteers of all ages through a Y- stethoscope to compare measures; and
- observation of protocol technique using a checklist.
Certification requires a score of 100 per cent on the audio-video tape test. Correct answers on the audio-video tape test require the examiner’s answers and the standardized test answers to be within +/- 2mm mercury (Hg) on 92 per cent of 24 measures (12 systolic, 12 diastolic), and within +/- 4mm Hg on 100 percent of 24 measures (12 systolic, 12 diastolic). For more information on quality assurance and control, see Ostchega et al. (Ostchega et al).
For more details on the QA/QC process for this component, please refer to the Physician Section of the MEC Operations Manual located on the NHANES website at the following link:
https://wwwn.cdc.gov/nchs/nhanes/continuousnhanes/default.aspx?BeginYear=2009
Analytic Notes
Changes Since 2007-2008:
There was no change since 2007-2008.
Exam sample weights should be used for analyses. Please refer to the NHANES Analytic Guidelines (https://wwwn.cdc.gov/nchs/nhanes/analyticguidelines.aspx) and the on-line NHANES Tutorial (https://www.cdc.gov/nchs/tutorials/) for further details on the use of sample weights and other analytic issues.