Can Sleep Studies Be Inaccurate? Here’s What To Know

Sleep studies are a useful tool for diagnosing sleep disorders like sleep apnea. But how accurate are they really?

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Illustration of sleep study results and accuracy

If you’re considering a sleep study or have recently undergone one, you know that they’re not exactly fun. If you have to go to a lab, there are electrodes and other machinery that doesn’t exactly promote a good night’s sleep. Home tests might be less frustrating, but you may have heard they can give mixed results. 

That might lead you to ask, can sleep studies be inaccurate? If you undergo a sleep study and it doesn’t catch anything, can you be sure there’s not a lurking disorder?   

In truth, sleep studies aren’t always accurate, especially home tests. Still, they’re very useful in many situations. 

Below, we’ll discuss sleep studies in full. We’ll talk about the pros and cons of lab tests vs. home tests and their accuracy. That way, you can decide which tests to undergo and what to do with the results. 

Sleep Studies: An Overview 

Sleep studies are a series of tests that measure sleep quality, allowing doctors to diagnose sleep issues such as sleep apnea, restless leg syndrome, and other parasomnias. Given the prevalence of obstructive sleep apnea (OSA) in particular, sleep studies are vital diagnostic tools. 

Obstructive Sleep Apnea and Sleep Studies

Researchers estimate that OSA affects more than 1 billion people globally, putting sufferers at a higher risk of stroke, heart disease, and other illnesses.  

If you suspect you have OSA, undergoing a sleep study may be a crucial step in getting proper treatment. But what if the sleep study says you don’t have anything wrong despite numerous symptoms like snoring and next-day fatigue? Can sleep study results be wrong? 

Two Types of Sleep Studies

Sleep study accuracy depends on the type of sleep study you undertake.

Doctors use two types of sleep studies to diagnose OSA: polysomnography (PSG) and home sleep tests (HSTs)

PSGs are the gold standard when it comes to sleep studies. They are generally accurate, and doctors have been using them for decades to diagnose common sleep issues. 

Home sleep tests are newer and may not be as accurate. However, they offer major benefits, like sleeping in your bed. 

Below, we’ll dive into each test in detail, including a discussion on how accurate they really are. 

Polysomnography 

Polysomnography tests use electrodes on your scalp, temples, legs, and chest to measure certain sleep markers. A doctor will also observe you as you sleep. Between the electrodes and the physician’s observations, a PSG test measures: 

  • Eye movement
  • Blood pressure
  • Brain activity
  • Heart rate
  • Skeletal movements
  • Breathing patterns
  • Noises such as snoring 

PSGs must occur in a lab setting, either in a hospital or a sleep clinic, meaning you must spend the night away from home. 

Because they measure so many different markers, diagnoses from PSG tests tend to be accurate, especially when a doctor suspects OSA. However, there are some sleep issues that PSGs aren’t as great at catching. Night seizures, for example, may happen too infrequently to be seen in one night of observed sleep. 

During a PSG test, the sleeper may also experience the “first-night effect.” A first-night effect is when someone has trouble sleeping in a new environment. Disturbed and disrupted sleep from being in a hospital or clinic bed may lead to an underdiagnosis of OSA. 

Pros

  • PSGs are very accurate, especially when diagnosing sleep apnea. 
  • PSGs may also reveal other sleep issues that a home test is unable to catch, like restless leg syndrome.

Cons

  • PSGs require a physician and specialized equipment, making them very expensive.
  • PSGs aren’t comfortable, and sleeping in a hospital bed may create the first-night effect. The first-night effect may make it hard to catch very mild OSA. 
  • PSGs only study one night of sleep, so conditions like night seizures may be difficult to catch. 

Home Sleep Tests

Home sleep tests use simple equipment that patients can operate independently, including a finger oxygen reader, chest belt, and nasal tube. They can measure basic sleep patterns, but they don’t provide a ton of information. That can make it tricky for a doctor to make an accurate diagnosis using an HST. 

However, home sleep tests are very cost-effective and convenient. When you use a home sleep test, you sleep in your bed. There’s no need to travel to a sleep center or pay for a physician to observe your sleep. 

For this reason, insurance companies tend to love home sleep tests. And in some cases, a home sleep test should work well. If a doctor suspects you to have moderate to severe sleep apnea, a home sleep test can catch enough information to make an official diagnosis. 

However, home tests can only catch moderate to severe OSA. They can’t catch other forms of sleep apnea or other sleep disorders. They also aren’t good at detecting mild OSA. 

Pros

  • Home sleep tests don’t require a physician or special equipment, making them cost-effective.
  • You can perform a home sleep test in the comfort of your bed. You don’t have to spend the night in a clinic.

Cons

  • Home sleep tests aren’t as accurate as PSGs. They can provide false negatives if you have a mild form of OSA. 
  • Home sleep tests don’t work for any condition other than OSA.

Frequently Asked Questions

Before we go, let’s answer a few common questions about sleep tests and sleep disorders. 

When Is a Home Sleep Apnea Test Appropriate? 

A home sleep apnea test is appropriate when a doctor suspects you have moderate to severe obstructed sleep apnea. 

What Can Mimic Sleep Apnea? 

General fatigue, hypothyroidism, depression, and certain medication side effects can mimic sleep apnea symptoms.

Can Anxiety Be Mistaken for Sleep Apnea? 

Anxiety and sleep apnea can cause fatigue which causes patients to mistake one for the other. A sleep study can help determine what’s happening.

Can Sleep Apnea Be a Symptom of Something Else?

Certain diseases such as heart failure and Parkinson’s can increase your risk of developing sleep apnea. However, sleep apnea can also exist on its own without other conditions. 

So, Can Sleep Studies Be Inaccurate? 

If you’re considering a sleep study, you might wonder, can a sleep study be wrong?

Typically, PSGs are accurate because they provide physicians with detailed information using multiple measures. Home sleep tests are more likely to have inaccuracies because they don’t measure as many patient inputs resulting in less information for the physician to diagnose. So, it’s easier to miss something.  

Although they are not perfect, sleep tests are still valuable. Sleep tests help pinpoint sleep disorders that contribute to poor health. If a home test doesn’t show evidence of a disorder your doctor still suspects, you can always try a more accurate polysomnography test. 

Nate Devore
Nate Devore
For over 15 years Nate has been obsessed with solving his own personal and difficult health challenges related to sleep, energy, and fatigue. As one of our sleep experts at sleeping.com, Nate is passionate about helping you get the best night’s sleep possible.

Medical Disclaimer: The content on this page should not be taken as medical advice or used as a recommendation for any specific treatment. Always consult your doctor before making any decisions.

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