Why Is 24-Hour Monitoring More Accurate Than a Single Reading?

Blood pressure naturally fluctuates throughout the day and night. It rises during physical activity, stress, and caffeine consumption, and falls during rest and sleep. A single reading taken in a doctor's clinic captures only one moment — and may not represent your true average blood pressure.

Two common phenomena make single readings particularly unreliable:

White Coat Hypertension

Some patients experience elevated blood pressure readings in a clinical environment due to anxiety or stress — even though their blood pressure is normal during the rest of the day. This is known as white coat hypertension. Without 24-hour monitoring, these patients may be unnecessarily diagnosed with hypertension and prescribed medication they do not need.

Masked Hypertension

The opposite can also occur. Some patients have normal blood pressure readings in the clinic but elevated blood pressure during daily life — particularly during work, exercise, or overnight. This is called masked hypertension and carries real cardiovascular risk that a clinic reading alone would miss.

24-hour ABPM resolves both of these problems by recording blood pressure repeatedly across a full day and night cycle, capturing the true pattern of your blood pressure.

When Might Your Doctor Refer You for ABPM?

Your GP or specialist may refer you for 24-hour blood pressure monitoring for a number of clinical reasons:

• Suspected white coat hypertension — elevated clinic readings in a patient who may have normal blood pressure outside the clinic
• Suspected masked hypertension — normal clinic readings in a patient with cardiovascular risk factors
• Confirming a new diagnosis of hypertension — before starting long-term medication
• Assessing blood pressure control on existing medication — to determine whether current treatment is effective across the full 24-hour cycle
• Evaluating resistant hypertension — blood pressure that remains elevated despite multiple medications
• Assessing overnight blood pressure — nocturnal blood pressure patterns carry independent cardiovascular risk
• Pre-operative blood pressure assessment — before planned surgery
• Pregnancy-related blood pressure concerns — monitoring for pre-eclampsia or gestational hypertension
• Assessing symptoms such as dizziness, headaches, or visual disturbance that may be related to blood pressure fluctuations

What to Expect

At Your Fitting Appointment

The fitting appointment takes approximately 15 minutes. A cardiac technician will:

• Place a blood pressure cuff on your non-dominant arm — this is the same type of cuff used for a standard blood pressure reading but slightly smaller
• Connect the cuff via a thin tube to a small recording device — about the size of a mobile phone — worn on a belt or strap
• Take several test readings to confirm the monitor is recording correctly
• Explain how to wear the device and what to expect over the monitoring period

During the 24-Hour Recording Period

Once fitted, you leave the clinic and go about your normal activities. The monitor will automatically inflate the cuff and take a reading at regular intervals — typically every 20 to 30 minutes during the day and every 30 to 60 minutes overnight.

During the recording:

• Continue your normal routine — work, exercise, meals, sleep
• When the cuff inflates, stop what you are doing, relax your arm by your side, and stay still until the reading is complete — this takes about 30 seconds
• Keep a simple diary of your activities — note times you eat, exercise, take medication, experience stress, and go to sleep and wake up
• Do not shower, bathe, or get the monitor wet
• You may find the overnight inflations briefly wake you — this is normal and most patients adjust

Returning the Monitor

After 24 hours, return to the clinic to have the monitor removed. This takes only a few minutes. The data is downloaded and a report is generated by a cardiologist for your referring doctor.

After the Test

The cardiologist will analyse the full 24-hour recording, including daytime averages, night-time averages, overall averages, and the pattern of blood pressure variation across the day. The report is sent to your referring doctor, typically within 48 to 72 hours.

Key findings that the report may identify include:

• Sustained hypertension — consistently elevated blood pressure across day and night
• White coat hypertension — elevated clinic readings with normal ambulatory readings
• Masked hypertension — normal clinic readings with elevated ambulatory readings
• Non-dipping pattern — blood pressure that does not fall normally during sleep, which carries additional cardiovascular risk
• Adequacy of current medication — whether treatment is controlling blood pressure across the full 24-hour period

Where to Have ABPM in South-East Queensland

SmartCare Diagnostics offers 24-hour ambulatory blood pressure monitoring at five locations:

• Springfield — SmartCare Diagnostics, Springfield Central
• Upper Mt Gravatt — SmartCare Diagnostics
• North Lakes — SmartCare Diagnostics
• Capalaba — SmartCare Diagnostics
• Ipswich — SmartCare Diagnostics

For eligible Medicare cardholders, 24-hour blood pressure monitoring is bulk billed. A valid referral from your GP or specialist is required.

To book an ABPM test or refer a patient, contact SmartCare Diagnostics on bookings@smartcd.com.au or visit smartcd.com.au.

Frequently Asked Questions