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Obstructive Sleep Apnoea

Sleep Studies & Referral

OSA can be diagnosed during a sleep study conducted either in a laboratory or at home. To qualify for a Medicare rebate for a home-based study, patients need to score 8 or more on ESS AND 5 or more on OSA 50 OR 3 or more on STOP-Bang.

OSA can be diagnosed during a sleep study or polysomnography (PSG) conducted either in a sleep laboratory or increasingly via a home-based study.

The pathway to having a sleep study can be through referral to a sleep or respiratory specialist who then organises the study or under certain criteria by direct referral from the GP. Reasons to consider referral to a sleep or respiratory medicine specialist are shown in the table below.

Table. Referral to a sleep or respiratory medicine specialist assessment requirements

A sleep specialist assessment is required if:

  • Very severe OSA
  • Excessive daytime sleepiness (ESS ≥ 16)
  • Sleepiness-related accident
  • OSA and patient represents a significant driving risk
  • OSA and high-risk occupation e.g., commercial driver, heavy machinery operator
  • Severe morbid obesity (BMI ≥ 45 kg/m2)
  • Alcohol abuse
  • Chronic opioid use
  • Heart failure
  • Neuromuscular or chest wall deformity
  • Uncontrolled psychological or psychiatric disorders
  • COPD (with FEV1/FVC ≤ 70% and FEV1 ≤ 50% predicted)
  • Supplemental oxygen required
  • Waking oxygen level ≤ 92%
  • Serum bicarbonate ≥ 28 mmol/L
  • Awake hypercapnia or sleep hypoventilation syndrome (e.g., CO2 ≥ 45 mmHg or SpO2 ≤ 90% for ≥ 30% of total sleep time on the diagnostic study)
  • Other significant sleep, respiratory, or cardiac disorders

The gold standard test for diagnosing OSA is with in-laboratory full polysomnography (PSG) with a sleep scientist in attendance throughout the night. However, in-laboratory PSG is limited in its availability, labour intensive and costly, so increasing attention has been focused on home sleep study testing (set up initially by a sleep scientist and patient proceeds with the overnight test at home unattended, or where the patient is able to set it up themselves). Traditionally, sleep studies have been divided into four categories.1

Table. Levels of sleep study relevant to OSA

  • Level 1 Full polysomnography (PSG) in sleep laboratory, attended by sleep scientist, comprising ≥7 channels
  • Level 2 Full PSG at home, unattended by sleep scientist, comprising ≥7 channels
  • Level 3 Portable testing at home, attended or unattended by sleep scientist, comprising 3-6 channels
  • Level 4 Portable testing at home, unattended by sleep scientist, comprising 1-2 channels

≥7 channels include airflow, oxygen saturation, respiratory effort, electrocardiography (ECG) and electroencephalography (EEG), limb movemen
3-6 channels include monitoring of breathing parameters without sleep assessment
1-2 channels include airflow, oxygen saturation, or heart rate

Choosing to order a sleep study at home has advantages (e.g. Increased patient comfort, shorter waiting time, avoids using hospital beds) and disadvantages (10% failure rate, patient or staff need to set up, no video recording made). A level 2 study is the most robust home study comprising ≥ 7 channels. In the correct clinical setting, this can produce equivalent results to a full in-laboratory diagnostic study. Level 3 or 4 home studies have more limited monitoring, between 1 to 4 channels. Level 3 and 4 studies have been shown to have reasonable diagnostic accuracy for confirming OSA in patients with a high pre-test probability of moderate-to-severe OSA without other significant medical or sleep comorbidities, and may be useful in improving access to diagnostic services, particularly in rural and remote regions. MBS reimbursement is currently unavailable for level 3 and 4 sleep study testing. Level 3 studies are being provided by some commercial sleep study providers, however, quality cannot be guaranteed in the absence of a professional accreditation process.

To help prioritise and reduce waiting lists, home studies may also be appropriate in some settings as a screening tool for patients with high pre-test probability of OSA (e.g. sleepy obese patients who snore and take antihypertensive drugs). Home-based tests (e.g. level 4 testing using two channels; oximetry and nasal pressure, e.g. ApneaLink) can be useful to rule in OSA in these patients, but not to rule out OSA; the tests have high specificity and high sensitivity when compared to full PSG (level 1). Therefore, if there is a strong clinical suspicion of OSA and the limited channel study is negative, the diagnosis should not be excluded without an in-laboratory sleep study and specialist review.

Patients who require urgent in-laboratory assessment include those with unstable cardiovascular status (e.g. nocturnal angina or recurring cardiogenic pulmonary oedema), hypercapnic respiratory failure, high pre-test probability of OSA who are about to undergo major surgery, and history of significant drowsiness while driving.

The model of care for OSA is area specific; rural services may differ from urban services regarding access to a sleep physician and sleep laboratory (monitored polysomnography) and be more dependent on home-based sleep studies (unmonitored polysomnography, overnight monitoring of respiration, oxygen saturation, and pulse, or pulse and oximetry monitoring only).2

Of note, to avoid conflicts of interest prescription of CPAP should not be affected by the financial interest in the selling of CPAP machines (Australasian Sleep Association. Best practice guidelines for the provision of CPAP therapy).

MBS criteria for sleep study

Current MBS criteria state that GPs can directly refer eligible patients for assessment of OSA using diagnostic home-based (unattended) (item 12250) or laboratory-based (item 12203) sleep studies if approved assessment tools have been used and suggest that the patient has a high pre-test probability of symptomatic, moderate-severe OSA. This would allow GPs to expedite diagnosis and treatment in a highly symptomatic group of patients with OSA. 3 A high pre-test probability of symptomatic, moderate-severe OSA is confirmed by an OSA50 score ≥5, STOP-BANG score ≥3, or high risk on the Berlin Questionnaire; and an elevated Epworth Sleepiness Scale score ≥ 8. GPs can also continue to refer patients to a respiratory and sleep physician for further investigation. Clinics can offer home-based sleep studies that are 100% bulk billed to Medicare for all patients with a Medicare card.

MBS description for item 12250 – home PSG

MBS description for item 12203 – sleep laboratory PSG

(a) the patient has, before the overnight investigation, been referred to a qualified adult sleep medicine practitioner by a medical practitioner whose clinical opinion is that there is a high probability that the patient has OSA; and

(b) the investigation takes place after the qualified adult sleep medicine practitioner has:

confirmed the necessity for the investigation; and

communicated this confirmation to the referring medical practitioner.

Table. Medicare Benefits Schedule (MBS) Diagnostic Services for Sleep Disorders 4

When referring, include the following information:

Patient details

  • Name, address, phone, date of birth
  • Whether an interpreter is required and if patient is not an Australian resident

Clinical details

  • Reason for referral, specific treatment requested, and start date
  • Medical history, current medications, allergies
  • Examination findings, investigations carried out and results, and management so far

General practitioner details

  • Name and practice, practice address, phone, and fax numbers


AHI - Apnoea-Hypopnoea Index
BBTi - Brief Behavioural Therapy for Insomnia
BMI - Body Mass Index (kg/m2)
BQ - Berlin Questionnaire
CBTi - Cognitive Behavioural Therapy for Insomnia
CELL - Coblation Endoscopic Lingual Lightening
COPD - Chronic Obstructive Pulmonary Disease
CVA - Cerebrovascular Accident
CPAP - Continuous Positive Airway Pressure
CSA - Central Sleep Apnoea
DASS - Depression Anxiety Stress Scale
DBAS - Dysfunctional Beliefs and Attitudes about Sleep
DBP - Diastolic Blood Pressure
DIMS - Difficulties Initiating and/or Maintaining Sleep
DISE - Drug-Induced Sleep Endoscopy
DISS - Daytime Insomnia Symptom Scale
ENT - Ear Nose and Throat
ESS - Epworth Sleepiness Scale
FOSQ - Functional Outcomes of Sleep Questionnaire
FSH - Follicle-Stimulating Hormone
FTP - Friedman Tong Position
GP - General Practitioner
HANDI - RACGP Handbook of Non-Drug Interventions
HGNS - Hypoglossal Herve Htimulation
ISI - Insomnia Severity Index
K10 - Kessler Psychological Distress Scale
MAD - Mandibular Advancement Device
MAS - Mandibular Advancement Rplint
MBS - Medicare Benefits Schedule
MMA - Maxillomandibular Advancement Surgery
MRA - Mandibular Repositioning Appliance
ODI - Oxygenation Desaturation Index
OSA - Obstructive Sleep Apnoea
PLMD - Periodic Limb Movement Disorder
PT - Positional Therapy
PTSD - Post-Traumatic Stress Disorder
PSG - Polysomnography
QSQ - Quebec Sleep Questionnaire
REM - Rapid Eye Movement
RFTB - Radiofrequency Thermotherapy of the Tongue Base
SBP - Systolic Blood Pressure
SCI - Sleep Condition Indicator
SE - Sleep Efficiency
SF36 - Short-Form (36) Health Survey
SMILE - Submucosal Minimally Invasive Lingual Excision
SNRIs - Serotonin-Norepinephrine Reuptake Inhibitors
SOL - Sleep Onset Latency
SSRI - Selective Serotonin Reuptake Inhibitors
TFTs - Thyroid Function Tests
TIB - Time In Bed
TORS - Transoral Robotic Surgery
TST - Total Sleep Time
UPPP - Uvulopalatopharyngoplasty
WASO - Wake After Sleep Onset

Quick links


  1. Hamilton GS, et al. Update on the assessment and investigation of adult obstructive sleep apnoea. Aust J Gen Pract. 2019;48(4):176-81
  2. Chai-Coestzer CL, et al. Primary care vs specialist sleep center management of obstructive sleep apnoea and daytime sleepiness and quality of life: a randomized trial. JAMA 2013; 309(10): 997-1004
  3. Hamilton GS, Chai-Coetzer CL. Update on the assessment and investigation of adult obstructive sleep apnoea. Aust J Gen Pract 2019 ;48
  4. www.mbsonline.gov.au/internet/mbsonline/publishing.nsf/Content/Factsheet-SleepDisorders