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. 2026 Sep;72(9):554. doi: 10.46747/cfp.7209554

Blood pressure measurement techniques

Tony Nickonchuk 1, Adrienne J Lindblad 2, Danielle Perry 3, Scott Garrison 4
PMCID: PMC13566721  PMID: 42728063

Clinical question

Do recommended blood pressure (BP) measurement techniques impact the accuracy of readings?

Bottom line

Cuff size, arm position, bladder distention, and leg crossing affect systolic BP (SBP) and diastolic BP (DBP) measurement accuracy (1 mm Hg lower to 20 mm Hg higher). Thin clothing does not impact readings. A 5-minute rest before measurement may give more accurate readings if SBP is 140 mm Hg or higher. Hypertension Canada recommendations are reasonable.

Evidence

Results are statistically significant unless indicated.

  • Larger, higher-quality randomized crossover trials are reported due to limitations of systematic reviews.1

  • Cuff size (195 patients): Compared to an appropriate cuff size,2 a larger cuff (ie, small arm with regular cuff) resulted in a 3.6 mm Hg SBP decrease and a 1.3 mm Hg DBP decrease. A smaller cuff (ie, large arm with regular cuff) increased SBP by 4.8 mm Hg and DBP by 1.8 mm Hg; an extra-large arm using a regular cuff increased SBP by 19.5 mm Hg and DBP by 7.4 mm Hg.

  • Arm position (supported at heart level, hand on lap, or arm hanging at side [133 patients])3: Lap increased SBP by 3.9 mm Hg and DBP by 4.0 mm Hg compared with supported. Side increased SBP by 6.5 mm Hg and DBP by 4.4 mm Hg compared with supported at arm level.

  • Leg position (111 patients)1: Crossed legs at knee versus feet on ground increased SBP to 8 from 3 mm Hg, and increased DBP by 2 mm Hg. No difference when legs were crossed at the ankles.

  • Rest period (113 patients)4: No rest versus 5-minute rest found no meaningful difference in patients with an SBP of less than 140 mm Hg. For those with an SBP of 140 mm Hg or greater, results were inconsistent and ranged from no effect to 4 mm Hg or more increase.

  • Clothing (201 participants)1: No difference between thin-sleeved (<2 mm) and bare-arm measurements.

  • Bladder (172 women; ultrasound-confirmed full bladder; not randomized)1: Full bladder versus empty resulted in an increase of 4.2 mm Hg in SBP and 2.8 mm Hg in DBP.

  • Talking: May raise SBP by 4 to 19 mm Hg, but suboptimal randomization processes were used.1

  • Environment: No difference between quiet and private, and noisy or public environments.5

Context

  • A 5 mm Hg reduction in SBP reduces major cardiovascular events by 10%; small measurement errors may be clinically meaningful.6

  • Hypertension Canada’s recommended measurement techniques7 align with protocols used in trials.

  • Automated office and home measurements using standardized techniques correlate more closely with awake ambulatory measurements than manual office readings.8

  • Guidelines recommend validated, automated devices for measurement.7

Implementation

Lower SBP targets (<130 mm Hg) lower the risk of cardiovascular events versus higher targets (<140 mm Hg) (eg, 5% versus 7% at 3 years).9 Lower targets are associated with more side effects (eg, hypotension and electrolyte abnormalities [7% versus 5%]).9 Initiate treatment at a BP of 140/90 mm Hg or greater (or ≥130/80 mm Hg with cardiovascular disease or 10-year risk ≥20%), with a target SBP of less than 130 mm Hg for all patients if tolerated.9 If busy, measurements can be taken without a 5-minute rest. If the initial reading is 140/90 mm Hg or greater, average repeat readings after rest to reduce variability.10

Tools for Practice articles are adapted from peer-reviewed articles at http://www.toolsforpractice.ca and summarize practice-changing medical evidence for primary care. Coordinated by Dr Adrienne J. Lindblad, articles are developed by the Patients, Experience, Evidence, Research (PEER) team and supported by the College of Family Physicians of Canada. Feedback is welcome at toolsforpractice@cfpc.ca.

Footnotes

Competing interests

None declared

References

  • 1.Kallioinen N, Hill A, Horswill MS, Ward HE, et al. Sources of inaccuracy in the measurement of adult patients’ resting blood pressure in clinical settings: a systematic review. J Hypertens. 2017. Mar;35(3):421-41. doi: 10.1097/HJH.0000000000001197. [DOI] [PMC free article] [PubMed] [Google Scholar]
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  • 10.Einstadter D, Bolen SD, Misak JE, Bar-Shain DS, et al. Association of Repeated Measurements With Blood Pressure Control in Primary Care. JAMA Intern Med. 2018. Jun 1;178(6):858-60. doi: 10.1001/jamainternmed.2018.0315. [DOI] [PMC free article] [PubMed] [Google Scholar]

Articles from Canadian Family Physician are provided here courtesy of College of Family Physicians of Canada

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