The NHANES program suspended field operations in March 2020 due to the
coronavirus disease 2019 (COVID-19) pandemic. As a result, data collection for
the NHANES 2019-2020 cycle was not completed and the collected data are not
nationally representative. Therefore, data collected from 2019 to March 2020
were combined with data from the NHANES 2017-2018 cycle to form a nationally
representative sample of NHANES 2017-March 2020 pre-pandemic data. These data
are available to the public. Please refer to the Analytic Notes section for more
details on the use of the data.
This section provides data for three consecutive oscillometric blood pressure
(BP) measurements and other methodological measurements to obtain an accurate
BP. Pulse is also reported.
Auscultatory BP measurement in NHANES ended after the 2017-2018 survey cycle.
Additional details and results from a methodology study, comparing auscultatory
and oscillometric BP measurement, are available in an NCHS Vital and Health
Statistics Series 2 Report at NCHS
website (Ostchega et al, 2021).
All examined participants, 8 years and older, in the NHANES 2017-March 2020
pre-pandemic sample were eligible. 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, and A-V shunts. Also,
women who have had an axillary nodal biopsy or resection, or a unilateral
radical mastectomy do not have their blood pressure measured in the affected
Protocol and Procedure
All BP measurements are taken in the mobile examination center (MEC). Prior
to obtaining BP measurements, upper arm circumference is measured, which is done
to guide selection of cuff size. Details on the protocol for obtaining upper arm
circumference is described in the Anthropometry Procedures Manual.
After resting quietly in a seated position for 5 minutes; three consecutive
BP measurements were taken 60 seconds apart using a digital upper-arm electronic
measurement device, Omron HEM–907XL. This device has been previously validated
by both the Association for the Advancement of Medical Instrumentation (AAMI)
and the International Protocol of the European Society of Hypertension for
taking BP measurements in populations aged 13 years and older (White et al,
2002; Ombani et al, 2007; Ostchega et al, 2010).
BP measurements were taken in the right arm unless specific conditions
prohibited the use of the right arm, or if participants reported any reason that
the measurements should not be taken in the right arm.
The NHANES 2017-2018
examination procedure manuals are available on the NHANES website.
Quality Assurance & Quality
The BP examiners were certified for BP measurement through a training
program and followed a standardized protocol. In addition, every three months
the examiners were observed by subject matter experts to assure that BP readings
were obtained following the standardized protocol.
Data Processing and Editing
The following are some specifications used in capturing the BP data:
- Systolic BP cannot be greater than 300 mmHg;
- Systolic blood pressure must be greater than diastolic BP;
- If there is no systolic BP, there can be no diastolic BP. However, there
can be a systolic measurement without a diastolic measurement.
The COVID-19 pandemic required suspension of NHANES 2019-2020 field
operations in March 2020 after data were collected in 18 of the 30 survey
locations in the 2019-2020 sample. Because the collected data were not
nationally representative, these data were combined with data from the previous
cycle (2017-2018) to create a 2017-March 2020 pre-pandemic data file. A special
weighting process was applied to the 2017-March 2020 pre-pandemic data file. The
resulting exam sample weights in the demographic data file should be used to
calculate estimates from the combined cycles. These exam sample weights are not
appropriate for independent analyses of the 2019-2020 data and will not yield
nationally representative results for either the 2017-2018 data alone or the
2019-March 2020 data alone. Please refer to the NHANES website for additional
information for the NHANES 2017-March 2020 pre-pandemic data, and for the
previous 2017-2018 public use data file with specific weights for that 2-year