What is the recommended method for confirming a diagnosis of hypertension in a 46-year-old patient with elevated office blood pressure readings, according to NICE (National Institute for Health and Care Excellence) CKS (Clinical Knowledge Summaries)?

How to Check Blood Pressure in the Office According to NICE CKS Principles

When blood pressure is elevated in the office, you should take at least 2 readings during the same visit (separated by at least 1 minute), and if these readings differ by more than 10 mm Hg, take a third reading—use the average of the last 2 readings as your office BP value. 1

Initial Office Measurement Protocol

Proper Measurement Technique

• Ensure the patient rests quietly for 3-5 minutes before measurement in a comfortable temperature room 1
• Have the patient empty their bladder and avoid smoking, coffee, or exercise for 30 minutes prior 1
• Use a validated electronic upper-arm cuff device with appropriate cuff size (covering 75-100% of arm circumference) 1
• Position the patient seated with back supported, feet flat on floor uncrossed, arm supported at heart level, and cuff on bare arm 1, 2
• Take no conversation during measurement 1

Number of Readings Per Visit

• Take 3 measurements at 1-minute intervals 1
• If the first 2 readings differ by >10 mm Hg or BP is unstable due to arrhythmia, take additional readings 1
• Record the average of the last 2 measurements as the office BP for that visit 1

Confirming the Diagnosis: Multiple Visits Required

How Many Office Visits

• Hypertension diagnosis requires elevated BP readings (≥140/90 mm Hg) at 2-3 separate office visits 1
• The exception is BP ≥160/100 mm Hg, which should be confirmed within a few days or weeks rather than months 1

Out-of-Office Confirmation is Essential

For office BP in the 130-159/85-99 mm Hg range, you must confirm with out-of-office monitoring (home BP or 24-hour ambulatory BP monitoring) before diagnosing hypertension, as 10-30% of these patients have white coat hypertension. 1, 3

Which Reading to Use as "Real"

The Gold Standard Approach

• Ambulatory BP monitoring (ABPM) is the reference standard for confirming hypertension diagnosis 1, 4
• ABPM thresholds: 24-hour average ≥130/80 mm Hg, daytime ≥135/85 mm Hg, nighttime ≥120/70 mm Hg 3
• ABPM is superior because it predicts cardiovascular events independent of office BP and detects masked hypertension in 25.8% of patients 1, 4

Practical Alternative: Home BP Monitoring

• If ABPM is unavailable, home BP monitoring is acceptable 1, 3, 4
• Protocol: Measure twice daily (morning and evening) for 7 days, taking 2 readings each time separated by 1 minute 3, 2, 5
• Discard day 1 readings and average all remaining measurements—hypertension threshold is ≥135/85 mm Hg 3, 5
• Home BP detects masked hypertension in 11.1% of patients, though less sensitively than ABPM 4

Critical Pitfalls to Avoid

Common Measurement Errors That Falsely Elevate BP

• Using incorrect cuff size, measuring over clothing, unsupported arm, full bladder, crossed legs, or talking during measurement all bias readings upward 1
• These errors lead to over-diagnosis and over-treatment of hypertension 1

Don't Rely on Single Visit Diagnosis

• Never diagnose hypertension based on a single office visit unless BP ≥180/110 mm Hg with evidence of end-organ damage 3
• Office BP alone has significantly lower specificity than ABPM, with only 60-70% of elevated office readings confirmed as true hypertension 1

White Coat Effect is Common

• 15-30% of patients with elevated office BP have white coat hypertension (normal out-of-office BP) 1, 6
• These patients are at intermediate cardiovascular risk and may not require immediate drug treatment 1, 6
• Conversely, 10-15% have masked hypertension (normal office BP but elevated out-of-office BP) who do require treatment 1, 3

Practical Algorithm Summary

1. First office visit: Take 3 readings at 1-minute intervals after 5-minute rest, average the last 2 1

2. If BP 130-159/85-99 mm Hg: Arrange out-of-office monitoring (preferably ABPM, alternatively 7-day home BP) before confirming diagnosis 1, 3

3. If BP ≥160/100 mm Hg: Repeat office measurement within days to weeks, then confirm with out-of-office monitoring 1

4. If BP ≥180/110 mm Hg: Confirm within 1 week and assess for hypertensive emergency 3

5. Use out-of-office BP as the definitive value for diagnosis, as it correlates better with cardiovascular outcomes and target organ damage than office BP 1, 4