National Health and Nutrition Examination Survey 1999-2000: effect of observer training and protocol standardization on reducing blood pressure measurement error

J Clin Epidemiol. 2003 Aug;56(8):768-74. doi: 10.1016/s0895-4356(03)00085-4.


Objective: We describe the National Health and Nutrition Examination Survey (NHANES) blood pressure (BP) observer training and protocol standardization and evaluate the quality of BP measurement.

Methods: The participants were persons aged 8 years and older who had their BP measured (n=7467) during NHANES 1999-2000. Cuff width/arm circumference ratio (CW/AC), end digit preference, and observer agreement were examined.

Results: In stepwise principal components multiple regression analysis, CW/AC accounted for less than 2% of variability R(2) in all readings. The frequencies for all end digits were close to 20% ("0" end digit=21% systolic and 23% diastolic). No overall observer effect was present for mean systolic BP readings. A significant observer effect (P<.0001) was detected for mean diastolic BP readings of <90 mm Hg. For readings of > or =90 mm Hg, there was no significant observer effect (P=.157).

Conclusion: We conclude that NHANES BP measurements do not demonstrate the variability that is commonly caused by observer and technical error.

Publication types

  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Adolescent
  • Adult
  • Aged
  • Aged, 80 and over
  • Bias
  • Blood Pressure Determination / instrumentation
  • Blood Pressure Determination / standards*
  • Child
  • Clinical Protocols
  • Diastole
  • Female
  • Health Surveys
  • Humans
  • Institutionalization
  • Male
  • Middle Aged
  • Quality Assurance, Health Care*
  • Regression Analysis
  • Sensitivity and Specificity
  • Systole