Types of Sleep Studies: HST, In-Center, MSLT, and more | Advanced Sleep Medicine Services, Inc.

Home Sleep Testing (HST)

HST is a type of diagnostic polysomnography which is self-administered by the patient in his/her home. It is used to diagnose sleep apnea by recording several channels of information: respiratory effort, pulse, oxygen saturation, nasal flow and snoring. HST is a cost-effective alternative to in-center sleep testing for many patients if it is highly likely that the patient has moderate to severe sleep apnea, and if the patient has no other significant medical issues such as pulmonary diseases, neuromuscular disease or congestive heart failure. HST cannot be performed on children and cannot diagnose other sleep disorders such as restless leg syndrome, periodic limb movement disorder or narcolepsy. These patients should be tested in a sleep center.

Most common reason for performing this test: Suspected sleep disorder, rule out suspected sleep disorder, can only diagnose sleep apnea (cannot diagnose other sleep disorders) and may require follow-up in-lab study. HST does not monitor EEG (brain activity).

CPT Code: 95806, G0399 or G0398 (based on insurance and type of testing device used)

In-center Polysomnography (PSG)

In-center polysomnography (PSG) records your brain waves, heartbeat and breathing as you sleep. It also charts your eye movements, limb movements and oxygen in your blood. PSG is also referred to as a diagnostic study, attended PSG, fully attended overnight sleep study. PSG can diagnose or rule out sleep disorders such as obstructive and central sleep apnea, restless leg syndrome (RLS) and more.

Most common reason for performing this test: Suspected sleep disorder, rule out suspected sleep disorder, rule out a sleep disorder such as sleep apnea before performing MSLT. In children, PSG may be used to diagnose or rule out suspected sleep apnea due to enlarged tonsils or adenoids, an obese child may have OSA due to excess fat around the airway

CPT Code: 95810 or 95782 (children under 6 years)

Split Night Polysomnography (50/50 or split)

Split night polysomnography is an in-center test that begins with diagnostic polysomnography and switches to PAP therapy titration once the patient shows sufficient apnea events. This test is often ordered when sleep apnea is highly likely and can eliminate the need for a second night sleep study if the titration is successfully completed.

Most common reason for performing this test: Suspected sleep disorder, rule out suspected sleep disorder, rule out sleep disorder before performing MSLT diagnose sleep apnea and THEN titrate on PAP device to find the correct pressure setting to treat sleep apnea.

CPT Code: 95811 or 95783 (children under 6 years)

Titration

A titration study is performed when a patient has been previously diagnosed with sleep apnea (either with an in-center or in-home sleep study) and is used to determine the optimal PAP settings which eliminate all or most apnea events.

Most common reason for performing this test: Patient was previously diagnosed with sleep apnea and is placed on PAP the entire night, pressure is titrated (moved up and down). A patient may return for a titration after changes in health, such as major weight loss or gain.

CPT Code: 95811 or 95873 (children under 6 years)

Bi-level or BiPAP Titration

A titration study is performed when a patient has been previously diagnosed with sleep apnea (either with an in-center or in-home sleep study) and has not found an optimal CPAP pressure. Bilevel or BiPAP may be more comfortable for some patient with higher pressure requirements as it has two pressure settings: the prescribed pressure for inhalation (ipap), and a lower pressure for exhalation (epap).

Most common reason for performing this test: Patient was previously diagnosed with OSA and has tried CPAP but was not comfortable with the high pressure or events were not eliminated. Patient is placed on bi-level PAP the entire night, pressure is titrated (moved up and down) to find optimal pressure that eliminates most events.

CPT Code: 95811 or 95873 (children under 6 years)

Adaptive Servo Ventilation (ASV) Titration

An ASV titration study is performed when a patient has been previously diagnosed with sleep apnea (either with an in-center or in-home sleep study) and may benefit from using an ASV PAP device.

ASV is similar to the continuous positive airway pressure (CPAP) therapy that is used in the treatment of obstructive sleep apnea but there are significant differences. When the ASV unit detects significant reductions or pauses in breathing, it intervenes with just enough support to maintain the patient's breathing at 90% of what had been normal for that individual just prior to the decrease in breathing. When the breathing is stable, ASV provides just enough pressure support to help keep the airway open, providing an approximately 50% reduction in the work of breathing.

Most common reason for performing this test: Patient was previously diagnosed with sleep apnea (usually central sleep apnea or Cheynes-Stokes respirations) and is placed on ASV the entire night, pressure is titrated (moved up and down) to find optimal pressure that eliminates most events.

CPT Code: 95811 or 95873 (children under 6 years)

Variable Positive Airway Pressure (AVAPs or IVAPs) Titration

A variable PAP titration study is performed when a patient has been previously diagnosed with sleep apnea (either with an in-center or in-home sleep study) and may benefit from using an variable PAP device.

Variable PAP is a continuous positive airway pressure (CPAP) mode used during noninvasive positive pressure ventilation. It delivers a preset inspiratory positive airway pressure (IPAP) and expiratory positive airway pressure (EPAP). BPAP can be described as a Continuous Positive Airway Pressure system with a time-cycled change of the applied CPAP level. CPAP, BPAP and other non-invasive ventilation modes have been shown to be effective management tools for chronic obstructive pulmonary disease and acute respiratory failure.

Most common reason for performing this test: Patient likely has ALS or Lou Gehrig's Disease or another form of muscular dystrophy. AVAPs is used to evaluate the use of this device to normalize shallow breathing.

CPT Code: 95811 or 95873 (children under 6 years)

MSLT (Multiple Sleep Latency Test)

A series of daytime naps (performed after PSG the previous night) is the standard tool used to diagnose narcolepsy and idiopathic hypersomnia (excessive sleepiness). The patient may need to stop medications 2 weeks before the test. MSLT measures the time elapsed from the start of a daytime nap period to the first signs of sleep, called sleep latency. The test is based on the idea that the sleepier people are, the faster they will fall asleep. Sleep apnea or excessive leg movements are much more likely to be the cause of excessive daytime sleepiness. Narcolepsy is rare. Achieving REM sleep in two or more naps could be consistent with a diagnosis of narcolepsy. The four most common symptoms of narcolepsy are hallucinations, sleep paralysis, excessive daytime sleepiness, cataplexy (loss of muscle control).

Most common reason for performing this test: Suspected narcolepsy. Additionally, a patient previously diagnosed with sleep apnea and currently using PAP therapy continues to complain of excessive daytime sleepiness may be tested to rule out narcolepsy.

CPT Code: 95805 (almost always ordered with overnight polysomnography the preceeding night)

MWT (Maintenance of Wakefulness Testing)

MWT is used to see if someone with a sleep disorder is responding well to treatment. Results of multiple tests may be compared over a period of time. This can show if treatment is helping a patient overcome sleepiness. The MWT may be used to evaluate how well a person with a sleep disorder is able to stay awake. This is critical when the person’s job involves public transportation or safety. The results of the test will be only one factor used to assess the potential risk of a work-related accident.

Most common reason for performing this test: MWT is used to see if someone with a sleep disorder is responding well to treatment. Results of multiple tests may be compared over a period of time. This can show if treatment is helping a patient overcome sleepiness. This test may be ordered for a person whose job involves public transportation or safety.

CPT Code: 95805

Types of Sleep Studies

Many sleep disorders can be diagnosed through a sleep study. Learn about the different types of sleep studies and why they are performed.

Sleep Studies We Perform

Home Sleep Testing (HST)

In-center Polysomnography (PSG)

Split Night Polysomnography (50/50 or split)

Titration

Bi-level or BiPAP Titration

Adaptive Servo Ventilation (ASV) Titration

Variable Positive Airway Pressure (AVAPs or IVAPs) Titration

MSLT (Multiple Sleep Latency Test)

MWT (Maintenance of Wakefulness Testing)

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