About 80% of moderate-to-severe sleep apnea goes undiagnosed. Not because it's hard to detect — because most people never know they should get checked.
The good news: there's a free, validated screening tool you can use in under 2 minutes. It's called STOP-BANG, and it's the same questionnaire used in many sleep clinics and pre-surgery assessments worldwide.
You can take the STOP-BANG test online here, or read on to understand how it works.
What Is Sleep Apnea?
Sleep apnea is a condition where breathing repeatedly stops and starts during sleep. The most common form, obstructive sleep apnea (OSA), happens when the throat muscles relax too much and block the airway.
Each breathing pause briefly wakes the brain (often without you remembering it) so you can resume breathing. Over a full night, this can happen dozens or even hundreds of times — fragmenting sleep and lowering oxygen levels.
Untreated sleep apnea is linked to:
- Daytime fatigue and difficulty concentrating
- High blood pressure
- Higher risk of heart disease and stroke
- Type 2 diabetes
- Increased risk of car accidents from drowsy driving
What Is the STOP-BANG Test?
STOP-BANG is an 8-question screening tool developed by Dr. Frances Chung at the University of Toronto in 2008. It's widely used because it's quick, validated in multiple studies, and works well for both men and women.
The name is an acronym for the 8 questions:
- S — Snoring loudly (loud enough to be heard through a closed door)
- T — Tired during the day, fatigued, or sleepy often
- O — Observed stopping breathing or gasping during sleep
- P — High blood Pressure (treated or untreated)
- B — BMI over 35
- A — Age over 50
- N — Neck circumference greater than 40 cm (15.7 in)
- G — Gender male
Each "yes" answer counts as 1 point. Total score: 0 to 8.
How to Interpret Your STOP-BANG Score
The original scoring categories used in clinical research are:
- 0–2 points: low risk of moderate-to-severe sleep apnea.
- 3–4 points: intermediate risk. Worth discussing with a doctor, especially if symptoms are present.
- 5–8 points: high risk. Strong recommendation to seek a clinical sleep evaluation.
Refined criteria can boost specificity: a score of 3+ combined with male sex, BMI over 35, or neck size over 40 cm raises the likelihood of moderate-to-severe apnea significantly.
Is STOP-BANG Reliable?
Multiple peer-reviewed studies have validated STOP-BANG against polysomnography (the gold-standard sleep study). Key findings:
- Sensitivity for moderate-to-severe apnea is around 90% at a cutoff of 3+ points — meaning the test rarely misses someone who has the condition.
- Specificity is lower — meaning a high score doesn't guarantee you have apnea, just that your risk is elevated enough to investigate.
This is exactly what a screening tool should do: cast a wide net and refer high-risk individuals to proper testing.
What to Do With Your Score
If you scored 0–2: your risk of moderate-to-severe apnea is low. If you still snore loudly or feel tired during the day, an app like SleepWell can track snoring and breathing patterns over time so you have data to share with a doctor if symptoms persist.
If you scored 3–4: bring this up at your next medical appointment. A primary care doctor can decide whether referral to a sleep specialist is warranted. Track your sleep at home in the meantime.
If you scored 5+: don't wait. Book an appointment with your doctor and mention your STOP-BANG score directly. They can refer you for a proper sleep study (either at-home or in a clinic).
How Apps Can Complement the Test
The STOP-BANG questionnaire captures risk factors, but it doesn't observe what actually happens during your sleep. Some Android apps add a layer of overnight tracking using the phone's microphone:
- Snoring intensity and duration — useful context for your doctor.
- Detection of breathing pauses — apps like SleepWell flag long quiet gaps in breathing sounds, especially when fused with heart rate from a Wear OS watch.
- Oxygen drops — when paired with Health Connect data from compatible smartwatches, apps can correlate apnea-suspect events with SpO2 dips.
None of this replaces a sleep study, but it provides weeks of real-world data instead of a single questionnaire snapshot.
Take the Test
Ready to check your risk? Take the free STOP-BANG screening test now. It takes about 2 minutes, no account required.
Sleep apnea is common, treatable, and dangerous when ignored. The STOP-BANG test is one of the simplest ways to find out if you should investigate further — and it costs nothing to take.
If your score raises a flag, the next step is a conversation with a healthcare professional. Apps and questionnaires are starting points, not endpoints.