Sleep Apnea Risk (STOP-BANG) Calculator

Understanding the STOP-BANG sleep apnea risk calculator — concept and principle

STOP-BANG is an eight-item yes/no questionnaire that estimates how likely you are to have obstructive sleep apnoea (OSA), in which the upper airway repeatedly collapses during sleep. It was built to screen patients before surgery and is now widely used to decide whether snoring or daytime sleepiness deserves a sleep study.

How it is calculated

Each "yes" scores 1 point and the score is the sum (0 to 8):

• Snoring loudly, Tired in the daytime, Observed stopped breathing, high blood Pressure.
• BMI above 35 kg/m², Age above 50, Neck above 40 cm, Gender male.

Bands: 0–2 low risk, 3–4 intermediate risk, 5–8 high risk. Following Chung and colleagues (2016), a score of 3–4 is moved up to high risk (escalated) when at least two STOP answers are yes together with male sex, BMI above 35 or neck above 40 cm.

The principle

The STOP items are symptoms of the disease: snoring and witnessed apnoeas come from a narrowed, collapsing airway, and tiredness reflects fragmented sleep. The BANG items are the strongest risk factors: neck fat and a high BMI narrow the airway, airway muscle tone declines with age, and OSA is more common in men. Each "yes" raises the probability, so the sum works as a simple risk ladder. Against overnight testing the tool is highly sensitive (it rarely misses significant OSA) but only moderately specific, so many high scorers turn out not to have it.

Worked example

1. Defaults: snoring 1, tired 1, observed 0, pressure 0, BMI 0, age 0, neck 1, male 1.
2. Score = 1 + 1 + 0 + 0 + 0 + 0 + 1 + 1 = 4.
3. 4 is in the 3–4 band, but two STOP items (snoring, tiredness) are yes and the person is male with a neck above 40 cm, so the result is high risk (escalated).

How to read the result

0–2 makes moderate-to-severe OSA less likely but does not rule it out when symptoms are strong. 3–4 justifies a sleep evaluation; 5–8 means a high probability and a clear reason to see a doctor. An escalated result carries the same message as a score of 5–8: the combination of symptoms and risk factors makes moderate-to-severe OSA more likely than the raw score suggests.

Common mistakes

• Counting occasional soft snoring as loud snoring.
• Answering "observed" as no just because you sleep alone.
• Measuring the neck over clothing or at the wrong level.

Frequently asked questions

Does STOP-BANG work for women?

Yes, but women tend to score lower because two items favour men. A symptomatic woman with a score of 3 still deserves evaluation.

What happens after a high score?

Usually a sleep study; if OSA is confirmed, options include CPAP, oral appliances and weight loss.

Why does neck size matter?

Fat around the neck presses directly on the upper airway, so it predicts collapse better than weight alone.

Sources: Chung F et al. STOP-Bang questionnaire: a tool to screen patients for obstructive sleep apnea. Anesthesiology 2008. · Chung F, Abdullah HR, Liao P. STOP-Bang Questionnaire: A Practical Approach to Screen for Obstructive Sleep Apnea. Chest 2016.