Diagnostic Approach for Obstructive Sleep Apnea
Polysomnography (PSG) is the gold standard diagnostic test for OSA and should be performed in conjunction with a comprehensive sleep evaluation under the supervision of a board-certified sleep medicine physician. 1
Initial Clinical Evaluation
Do not use clinical tools, questionnaires, or prediction algorithms alone to diagnose OSA—they have poor diagnostic accuracy and must be followed by objective testing. 1
The clinical evaluation must include:
Sleep History Components
- Nocturnal symptoms: snoring patterns, witnessed apneas, gasping/choking episodes, restless sleep, and nocturia 2, 3
- Daytime manifestations: excessive sleepiness (quantified by Epworth Sleepiness Scale), morning headaches, decreased concentration/memory, irritability, and fatigue 2, 3
- Associated conditions: obesity, hypertension, stroke, congestive heart failure, and diabetes 2, 3
Physical Examination Focus
- Anthropometric measurements: BMI and neck circumference 2
- Upper airway anatomy: modified Mallampati score, retrognathia, lateral peritonsillar narrowing, macroglossia, tonsillar hypertrophy, elongated/enlarged uvula 2
- Systems assessment: respiratory, cardiovascular, and neurologic examination 1
Diagnostic Testing Algorithm
For Uncomplicated Patients with Suspected Moderate-to-Severe OSA
Either in-laboratory PSG or home sleep apnea testing (HSAT) with a technically adequate device is acceptable. 1, 2, 3
- This applies to patients presenting with signs/symptoms indicating increased risk of moderate-to-severe OSA 1
- HSAT is appropriate when there are no complicating factors 3
Mandatory PSG Indications (Cannot Use HSAT)
PSG is required—not optional—for patients with: 1, 2
- Significant cardiorespiratory disease 1, 2
- Potential respiratory muscle weakness due to neuromuscular conditions 1, 2
- Awake hypoventilation or suspected sleep-related hypoventilation 1, 2
- Chronic opioid medication use 1, 2
- History of stroke 1
- Severe insomnia 1, 2
- Symptoms suggesting other sleep disorders 3
When Initial Testing is Negative or Inadequate
If a single HSAT is negative, inconclusive, or technically inadequate, PSG must be performed. 1
If the initial PSG is negative but clinical suspicion remains high, consider a second PSG. 1
Split-Night Protocol Option
A split-night diagnostic protocol may be used instead of full-night PSG when clinically appropriate, allowing diagnosis in the first half and treatment titration in the second half. 1
- This is a weak recommendation with lower certainty of benefit 1
- Clinical judgment determines appropriateness 1
Diagnostic Criteria for OSA
OSA is diagnosed when: 3
- ≥5 obstructive respiratory events per hour (apneas, hypopneas, or respiratory effort-related arousals) PLUS symptoms (daytime sleepiness, snoring, witnessed apneas, or awakenings with gasping/choking), OR
- ≥15 obstructive respiratory events per hour even without symptoms (due to cardiovascular risk) 3
Severity Classification by AHI
- Mild OSA: AHI 5-14 events/hour 2
- Moderate OSA: AHI 15-30 events/hour 2
- Severe OSA: AHI >30 events/hour 2
Critical Pitfalls to Avoid
Never rule out OSA based on absence of daytime sleepiness alone—many patients with severe OSA do not report sleepiness. 3
Self-reported symptoms are unreliable for diagnosis—objective testing with PSG or HSAT is always required. 3
Clinical prediction tools cannot substitute for PSG or HSAT—they have low diagnostic accuracy at all AHI thresholds and their harms outweigh benefits when used as sole diagnostic tools. 1
Supervision Requirements
All diagnostic testing must occur under supervision of a board-certified sleep medicine physician with comprehensive sleep evaluation before testing and adequate follow-up after testing. 1, 2
This ensures: 2
- Appropriate differential diagnosis consideration
- Proper interpretation of study findings
- Expert guidance in prescribing therapy
- Identification of associated medical conditions