Should blood pressure (BP) always be recorded in even numbers?

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Last updated: March 21, 2025View editorial policy

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From the Guidelines

Blood pressure should be recorded as accurately as possible, without rounding to even numbers, to ensure precise patient assessment and treatment decisions. In clinical practice, blood pressure readings are recorded as the exact measurements obtained, whether they are even or odd numbers, using modern digital blood pressure devices that can display readings in single-digit increments, including odd numbers like 121/79 mmHg 1. According to the 2017 ACC/AHA/AAPA/ABC/ACPM/AGS/APhA/ASH/ASPC/NMA/PCNA guideline for the prevention, detection, evaluation, and management of high blood pressure in adults, proper documentation of accurate BP readings is crucial, and recordings should be made using the nearest even number only when using the auscultatory technique, but this does not imply that all BP readings should be rounded to even numbers 1.

Key points to consider when recording blood pressure include:

  • Properly documenting accurate BP readings
  • Recording SBP and DBP as onset of the first Korotkoff sound and disappearance of all Korotkoff sounds, respectively
  • Noting the time of most recent BP medication taken before measurements
  • Averaging the readings, using an average of ≥2 readings obtained on ≥2 occasions to estimate the individual’s level of BP
  • Providing patients the SBP/DBP readings both verbally and in writing 1.

In real-life clinical medicine, recording blood pressure accurately, whether the reading is an even or odd number, is essential for making informed treatment decisions and ensuring the best possible patient outcomes. The practice of rounding blood pressure to even numbers is an outdated convention that is not supported by current medical standards and could potentially mask important clinical information 1.

From the Research

Blood Pressure Measurement

The question of whether blood pressure (BP) should always be recorded in even numbers is not directly addressed in the provided studies. However, the studies do discuss the importance of accurate blood pressure measurement and the various methods used to obtain these measurements.

Methods of Blood Pressure Measurement

  • The auscultatory method, which uses a stethoscope and sphygmomanometer, is considered the gold standard for non-invasive BP measurement 2.
  • Oscillometric devices, which use electronic sensors to measure BP, are also commonly used and can provide accurate measurements in most cases 3, 4.
  • The use of mercury devices is being restricted, and alternative methods such as aneroid sphygmomanometers are being recommended 5, 3.

Accuracy of Blood Pressure Measurement

  • Accurate BP measurement is essential for diagnosis and management of hypertension, and inaccurate measurements can lead to diagnostic errors and incorrect treatment decisions 2, 6.
  • Various factors can influence the accuracy of BP measurement, including patient positioning, cuff size, and correct use of the stethoscope 2.
  • Regular maintenance and recalibration of BP measuring equipment are necessary to ensure accuracy of readings 2.

Recording Blood Pressure Measurements

  • BP measurements are typically recorded as a fraction, with systolic and diastolic pressures measured in millimeters of mercury (mmHg) 2.
  • There is no specific guidance in the provided studies on whether BP should always be recorded in even numbers.

References

Guideline

Guideline Directed Topic Overview

Dr.Oracle Medical Advisory Board & Editors, 2025

Research

How to take and record a manual blood pressure measurement.

Nursing standard (Royal College of Nursing (Great Britain) : 1987), 2025

Research

Blood pressure measurement in research and in clinical practice: recent evidence.

Current opinion in nephrology and hypertension, 2004

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

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