Biostatistical Classification of a Single Elevated Blood Pressure Reading
This single elevated reading of 140/90 mmHg among otherwise normal home measurements represents measurement error or random variability in biostatistical terms, not a systematic error or true hypertension.
Understanding Blood Pressure Variability
Blood pressure inherently varies from moment to moment, and a single aberrant reading does not indicate true hypertension. 1 The European Society of Hypertension guidelines explicitly acknowledge that patients should be informed "that values may differ between measurements because of spontaneous blood pressure variability." 1
- This phenomenon reflects the inherent biological variability of blood pressure, which fluctuates continuously throughout the day due to physiological factors 1
- A single elevated reading in the context of consistently normal home measurements does not meet diagnostic criteria for hypertension 1
Biostatistical Classification
In biostatistical terminology, this represents:
- Random error (as opposed to systematic error or bias) - an unpredictable deviation from the true value that occurs by chance 1
- Type I error could apply if this single reading led to a false diagnosis of hypertension (false positive) 1
- Measurement variability - the natural fluctuation in repeated measurements of the same parameter 1
Clinical Context and Proper Assessment
Multiple measurements are required to establish a diagnosis of hypertension, specifically a minimum of 12 readings over 7 days for home blood pressure monitoring. 1
- Home blood pressure thresholds for hypertension are ≥135/85 mmHg on average, not based on a single reading 1
- The American Heart Association emphasizes that "BP varies with time, whichever method of measurement is used" 1
- Diagnostic decisions should never be based on isolated measurements but rather on patterns across multiple readings 1
Important Distinction from White-Coat Effect
This scenario differs from white-coat hypertension, which involves consistently elevated office readings with normal home readings 1. Your scenario describes a single aberrant home reading, not a pattern of office-home discordance.