Understanding the level of sleep studies is essential for diagnosing sleep disorders accurately. There are three different types of sleep studies a level 3, level 2, and level 1 sleep study each varying in complexity, cost, and monitoring requirements. Choosing the right option helps identify issues such as sleep apnoea and ensures effective treatment planning. Follow the article below to find the best solution for your needs with CPAP Discount Warehouse.
What is a sleep study?
A sleep study, also called polysomnography, is a painless overnight test that records how the body functions during sleep. It uses sensors and leads to monitor brain activity, breathing, oxygen levels, heart rate, and leg movements. This procedure helps detect sleep disorders such as sleep apnea, insomnia, excessive tiredness, and sleep-related breathing or movement problems.
There are five main types of sleep studies, each using different methods to assess specific sleep characteristics and disorders. By analyzing how your body responds during sleep, a sleep study can identify issues that may require treatment or lifestyle changes.
Level of sleep studies
Level 1 – Polysomnography – In-Lab
The Level 1 sleep study is used to determine the causes of excessive daytime sleepiness and to diagnose various sleep disorders. The Level 1 study records brain waves, heart rate, and breathing during sleep. It also records eye and limb movements and blood oxygen levels.
Level 1 tests are useful in particularly severe cases or when a sleep disorder unrelated to breathing or leg movements is suspected.
Level 1 polysomnography (PSG) in a sleep laboratory under the supervision of a sleep specialist, including ≥7 channels. Overnight diagnostic sleep study lasting at least 8 hours for patients aged 18 and older to confirm the diagnosis of a sleep disorder.
Level 2 – Polysomnography – At Home or Lab
Level 2 home sleep studies are a valuable tool for diagnosing sleep disorders, particularly obstructive sleep disorders. Level 2 studies are the most comprehensive home studies and include ≥ 7 channels. Under appropriate clinical conditions, these studies can provide results equivalent to those of a complete diagnostic study in a laboratory.
The main difference between Level 1 and Level 2 sleep studies lies in the conditions under which the studies are conducted and the scope of monitoring expected.
Level 3 – Home Sleep Apnea Test – HSAT
The Level 3 sleep test, also known as the Home Sleep Test (HSAT), measures respiratory airflow, breathing effort, oxygen content, and heart rate. This diagnostic test is used to monitor behavior during sleep and detect sleep apnea or other respiratory disorders.
The Level 3 sleep study is most suitable for people who suspect they have sleep apnea or are at risk of developing it. The diagnostic sleep study lasts at least 8 hours and is performed on patients over the age of 18 to confirm the diagnosis of a sleep disorder.
Sleep test results
During a sleep study, breathing is most commonly measured using small plastic nasal tubes that detect nasal pressure. These sensors identify periods when airflow is reduced or completely stops due to a partial or complete blockage of the upper airway. Each episode lasting more than 10 seconds is recorded as either a hypopnoea or an apnoea.
The total number of apnoeas and hypopnoeas is divided by the total sleep time to calculate the Apnoea-Hypopnoea Index (AHI) the number of partial or complete blockages per hour of sleep which is a key measure of sleep apnoea severity. The standard AHI ranges are:
<5 – Normal
5–15 – Mild obstructive sleep apnea
15–30 – Moderate obstructive sleep apnea
>30 – Severe obstructive sleep apnea
Your sleep study report will clearly display the AHI (sometimes referred to as the Respiratory Disturbance Index – RDI). While the overall AHI gives a strong indication of sleep apnoea severity, it is also important to review results by sleep position and sleep stage. For example, if you spend only a short time sleeping on your back during the study, the AHI may underestimate the severity if breathing issues are worse in that position. Your report will typically include a detailed table showing AHI values across different body positions and sleep stages to ensure accurate diagnosis and treatment planning.
>>> How is sleep apnea diagnosed? Sleep Apnea Testing
What types of sleep studies are provided by our partner - CLM Sleep?
Diagnostic and Investigative Services
A diagnostic sleep study, also known as a Level 1 sleep study, is a comprehensive overnight assessment performed in a hospital or accredited sleep clinic. Using advanced monitoring equipment, it tracks multiple sleep parameters to deliver the gold standard in diagnosing sleep disorders. This detailed evaluation provides crucial insights into sleep quality and helps identify conditions such as sleep apnoea, narcolepsy, and restless legs syndrome.
CPAP titration
A CPAP titration sleep study is a specialised test used to determine the optimal Continuous Positive Airway Pressure (CPAP) settings for people diagnosed with obstructive sleep apnoea. Conducted overnight in a hospital or dedicated sleep clinic, the study involves a sleep technologist closely monitoring you while you use a CPAP machine, which delivers a steady flow of air to keep the airway open during sleep. The goal is to identify the precise pressure level needed to effectively control OSA and support consistently restful sleep.
In-lab Polysomnography
Polysomnography actively monitors brain wave activity, blood oxygen levels, heart rate, and breathing throughout the night, while also tracking eye and leg movements. In Australia, this test is typically carried out overnight in a hospital-based sleep disorders unit or a dedicated sleep clinic to accurately assess and diagnose sleep-related conditions.
Home Sleep Studies
Home Sleep Test allow you to complete the assessment in the comfort of your own home, while recording key data such as body movements, heart rate, and blood oxygen levels. An Australian sleep physician then reviews these results alongside other details, such as an online sleep assessment, to provide a comprehensive and personalised sleep report.
Multiple Sleep Latency Test (MSLT)
The Multiple Sleep Latency Test (MSLT) is used to detect excessive daytime sleepiness by measuring how quickly a person falls asleep in a quiet environment during the day. Doctors use the MSLT to assess excessive daytime sleepiness and the underlying sleep disorders.
The MSLT is an objective test that measures the tendency to fall asleep under controlled conditions. The participant has 4-5 opportunities to fall asleep every two hours during their normal waking period.
Maintenance of Wakefulness Test (MWT)
The Maintenance of Wakefulness Test (MWT) is used to measure your level of alertness throughout the day, unlike sleep studies. This test shows whether you are able to stay awake for a certain period of time.
The MWT is a procedure that uses electrophysiological measurements to determine your ability to stay awake while sitting in a quiet, dark room. The Maintenance of Wakefulness Test (MWT) consists of a series of 40-minute tests, during which you will be asked to try to stay awake.
What can a sleep study diagnose?
A modern sleep test provides detailed data on heart rate, body movements, and blood oxygen levels, helping to diagnose sleep disorders such as sleep apnoea, sleep-related seizure disorders, sleep-related movement disorders, and sleep disorders that cause extreme daytime tiredness such as narcolepsy.
How much does a sleep study cost?
In Australia, sleep studies are generally classified into three main types to diagnose sleep disorders: Level 1 (in-lab) and Level 2 and 3 (home-based).
Level 1 Sleep Study (In-lab): Conducted overnight in a sleep clinic or hospital, this is the most comprehensive and accurate option, using full technician supervision and extensive monitoring. Costs typically range from $500 to $2,000, depending on the clinic and the level of testing required.
Level 2 Sleep Study (Home-based): Measures the same key indicators as Level 1 but is performed at home without technician supervision, making it more convenient and less expensive, usually $600 to $1,200.
Level 3 Sleep Study (Home-based): Focuses primarily on diagnosing sleep apnoea, monitoring airflow, heart rate, oxygen saturation, and respiratory effort. It is the most affordable option, generally $300 to $700.
**Note: The costs above do not include insurance coverage. To access Medicare rebates or private health insurance benefits, you will need a GP referral. Medicare may cover part or all of the cost, while private health insurance will reimburse according to individual policy terms.
>>> What is a Sleep study? 5 Steps to Get Tested for Sleep Apnea
FAQs
Is a sleep study covered by Medicare Australia?
Most patients experiencing moderate symptoms of sleep apnoea may be eligible for a Medicare bulk-billed Level 2 sleep study.
How does an in home sleep study work?
An at-home sleep study typically uses sensors to measure airflow through the nose and mouth and to track the movement of breathing muscles in the chest and abdomen.
Can a sleep study be wrong?
Avoid consuming caffeine or alcohol for at least eight hours before your sleep study, as both can interfere with normal sleep patterns and impact the accuracy of the test results.
Which sleep test is right for me?
The most reliable approach is to consult your doctor for personalised advice. However, in many cases you don’t need to request a referral or undergo a full polysomnography (PSG) immediately, as other sleep study options may be suitable first.
