White-coat and masked hypertension

With white-coat hypertension, your blood pressure is high at the clinic and normal at home. Masked hypertension is the reverse, and clinic checks miss it. You can find either one with a seven-day home average or a 24-hour monitor.

The four combinations

Your clinic number and your out-of-office number can each be high or normal.

You can’t tell which box you’re in from clinic visits alone, because you also need numbers from outside the clinic.

The lines, by setting

The US guideline uses 130/80 in the clinic and at home, and lower lines on a 24-hour monitor for the full day and for the night.

The US guideline writers worked out which 24-hour monitor numbers match each clinic number, and outcome studies later found similar values.

Why the doctor’s number runs higher

Part of the gap comes from the setting, and a rushed cuff check isn’t the same as a quiet measurement after 5 minutes of rest.

If your clinic number looks high, ask for a repeat at the end of the visit, seated and quiet, and then bring your home numbers.

How common they are

Estimates vary widely, since they depend on the group, the definition and the monitor. One review gave a range of 16 to 55 percent for white-coat hypertension found with home monitoring.

If your clinic numbers are normal, a home week is a cheap way to look. According to a 2026 review of the 2025 US guideline, checking outside the office may be reasonable to rule out masked hypertension in adults with a clinic number under 130/80.

What the risk looks like

These are hazard ratios compared with people who have normal blood pressure, so 1.36 means 36 percent higher.

Researchers don’t agree about white-coat hypertension. Some who pooled studies found added risk in people who are untreated, and others found none. A white-coat diagnosis doesn’t mean you’re in the clear, and you still need regular rechecks. The risk with masked hypertension is much closer to sustained hypertension. People often have no idea they have it, because every clinic visit looks fine.

You may see older pages quote a 2018 New England Journal of Medicine study of a Spanish registry, which gave masked hypertension a hazard ratio of 2.83. The authors retracted that paper in 2020 after finding errors in the data and analysis, so we don’t use it. In 2023 the Lancet published a corrected analysis of the same registry, with 59,124 patients. The researchers again found higher risk of death with masked and sustained hypertension, and found that 24-hour numbers predicted death better than clinic numbers.

How to find out

A home week

Take a seven-day home week with a validated upper-arm cuff in the right size. The how-to covers the setup, and the home average tool does the math.

Keep clinic numbers out of your home average. They measure something different, and mixing them in hides the gap you’re looking for.

A 24-hour monitor

An ambulatory monitor is a cuff you wear for a day and a night. It takes measurements on a schedule, including while you sleep. Ask your doctor for one if your home and clinic numbers disagree, if your home numbers are close to a line, or if you’re worried about your pressure at night. Home and 24-hour results don’t always match.

What to do with the answer

If you take medication and see a gap, keep taking it as prescribed and show the numbers to your prescriber. The 2025 US guideline says it’s important to rule out a white-coat effect before treatment is stepped up, so your log gives your doctor evidence to work with. Never change a dose on your own.

If you have chest pain, shortness of breath, back pain, weakness, numbness, vision change or trouble speaking, call emergency services, whatever the number. At a systolic (the top number) of 180 or higher, or a diastolic (the bottom number) of 120 or higher, with no symptoms, follow the emergency steps.