How Is Sleep Apnea Diagnosed?

Medically reviewed by Valerie Cacho, MD

Sleep apnea is diagnosed based on information from a physical exam, medical history, and certain sleep testing procedures. This sleep disorder can cause you to stop breathing for short periods while you sleep. Breathing restarts eventually, but the pattern of stopping and restarting can affect your airways and heart health.

You may have a hard time noticing symptoms of sleep apnea, so it's best to reach out to a healthcare provider if you think you have it. They may work with a sleep medicine specialist if they suspect you have sleep apnea. This may be known as your "care team."

Related: Why Do You Have Restless Legs?

Medical History

It's standard practice for a healthcare provider to ask you about your medical history at the initial appointment. They may ask you the following questions to learn more about your personal and family medical history, symptoms, and lifestyle habits:

• Are there any changes in your life that may be affecting your sleep patterns?

• Do you drink alcohol or use tobacco?

• Do you have a parent or sibling with a sleep disorder?

• Do you sleep on your back?

• Do you snore?

• Do you wake up in the middle of the night?

• Do you wake up in the mornings feeling tired or with a headache?

• What do your exercise and eating habits look like?

• What quality of sleep are you getting?

It's also common for a healthcare provider to discuss any other health conditions that you have that may increase your risk of sleep apnea. These conditions include:

• A history of heart attack and irregular heart rhythm

• High blood pressure

• History of stroke

• Obesity

• Type 2 diabetes

Physical Exam

There are no physical exams that exist to help healthcare providers diagnose sleep apnea, but they will likely:

• Check your weight

• Measure the circumference of your neck

• Measure your vitals (e.g., blood pressure, heart rate, temperature)

• Take a look inside your mouth and throat for any signs of an obstruction, such as a large tongue or inflamed tonsils

A healthcare provider may discuss your weight with you during your appointment. Research has shown that people who are overweight are twice as likely to develop sleep apnea, and those with obesity are four times as likely. Keep in mind that not all people with sleep apnea have obesity.

Procedures

A healthcare provider can use two procedures to diagnose you with sleep apnea: a laboratory polysomnography and a home sleep apnea test. A sleep medicine specialist typically reviews and interprets the results after the tests are complete.

Polysomnography

Healthcare providers consider polysomnography to be the gold standard of sleep apnea testing. This sleep study takes place in a laboratory designed to look much like a hotel room and involves wearing several monitors. A sleep medicine expert may also refer to this test as an "overnight sleep study."

A healthcare provider may require you to wear one or more of the following monitors while you sleep:

• Bands: Worn over your chest and abdomen to measure how your body functions and moves as you breathe

• Electrodes: Placed on your head to measure your brain waves or on your chest to measure your heart rate and rhythm

• Nasal cannula: A thin, flexible plastic that fits inside of your nose, which can measure your breathing and airway pressures

• Pulse oximeter monitor: Worn on your finger to measure your oxygen levels throughout the night

A sleep technician will be available at the laboratory (but not inside the room) to monitor your breathing, heart rate, oxygen levels, and movements. This test will also record how often you wake up at night due to snoring, gasping, or choking.

It's common for people who undergo this test to have difficulty sleeping. That's OK because several factors—such as testing anxiety and being away from your normal bed—can contribute to this.

Home Testing

Laboratory testing is the standard, but home sleep apnea testing is possible. Home sleep apnea testing has a sensitivity and specificity rate of about 79%, meaning it accurately diagnoses nearly four out of five people with sleep apnea. This percentage depends on the device used, pre-test probability, and likelihood of sleep apnea based on your initial symptoms.

Home sleep apnea tests involve applying monitors to yourself. These monitors will check your breathing, upper airway airflow, heart rate and oxygen levels. This form of testing doesn't always measure your leg movements or changes in positioning when you sleep, but some devices can.

At-home testing is generally safe for most people. A care team will likely recommend laboratory-based testing for more accurate measurements if you have heart or lung disease history.

Diagnostic Criteria

The care team or other sleep medicine experts will typically diagnose sleep apnea using a measurement called the apnea-hypopnea index (AHI). They calculate this measurement based on your results from laboratory or at-home testing. Apnea occurs when you stop breathing during your sleep. Hypopnea occurs when you are breathing, but your oxygen levels drop by at least 3% while you sleep.

A healthcare provider will use the AHI to measure whether you have sleep apnea and the severity of your condition. This assessment is based on scores, or numbers that are measured in events per hour of sleep. Events are incidents when your airway narrows to a significant amount while sleeping.

The scores for diagnostic criteria come in ranges that are different for children and adults. Here's a breakdown:

These results aren't the only measure a healthcare provider will use for diagnosis. They will consider your AHI results, symptoms, and overall health to determine the treatments that are right for you.

Related: What Causes Sleepwalking (Somnambulism)?

A Quick Review

It's a good idea to visit a healthcare provider for proper testing and diagnosis if you think you have sleep apnea. They will ask about your medical history and perform a physical exam. The healthcare provider can either recommend a lab-based or at-home sleep study. Receiving an accurate diagnosis can help a care team figure out treatments to improve your symptoms and quality of sleep. 

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