STOP-BANG Score — OSA Screening Calculator

Screen for obstructive sleep apnea risk using the STOP-BANG questionnaire. 8 yes/no questions with risk stratification, perioperative guidance, and predictive performance data.

About the STOP-BANG Score — OSA Screening Calculator

The STOP-BANG questionnaire is the most widely validated screening tool for obstructive sleep apnea (OSA), used in preoperative assessments, primary care, and sleep medicine referral triage. Its eight simple yes/no questions — Snoring, Tiredness, Observed apnea, high blood Pressure, BMI > 35, Age > 50, Neck circumference > 40 cm, and male Gender — can be answered in under two minutes without any laboratory testing or equipment.

OSA affects approximately 15-30% of men and 10-15% of women, but an estimated 80% of moderate-to-severe cases remain undiagnosed. Untreated OSA is independently associated with hypertension, atrial fibrillation, stroke, type 2 diabetes, motor vehicle accidents, and perioperative complications. The STOP-BANG score of ≥ 3 identifies patients at increased OSA risk with a sensitivity of 93% for moderate-to-severe OSA.

In the perioperative setting, a high STOP-BANG score triggers enhanced monitoring protocols: avoidance of unnecessary opioids, preference for regional anesthesia, lateral positioning, continuous pulse oximetry, and consideration of CPAP in the post-anesthesia care unit. This calculator provides score interpretation, risk stratification, and actionable clinical recommendations for each risk category.

Why Use This STOP-BANG Score — OSA Screening Calculator?

With 80% of moderate-to-severe OSA cases undiagnosed, STOP-BANG provides a rapid, no-cost screening pathway that can be administered in any clinical setting — the waiting room, preoperative clinic, or primary care visit. Identifying OSA early enables treatment (CPAP, oral appliances, weight loss) that reduces cardiovascular risk, improves quality of life, and prevents perioperative complications.

How to Use This Calculator

  1. Answer each of the 8 STOP-BANG questions as Yes or No.
  2. For "Observed apnea," select Unsure if no bed partner has reported this.
  3. Each Yes answer scores 1 point; the total ranges from 0 to 8.
  4. Review the risk classification (Low: 0-2, Intermediate: 3-4, High: 5-8).
  5. Check perioperative recommendations if the score is being used for surgical planning.
  6. For scores ≥ 3, discuss referral for formal polysomnography with the patient.

Formula

STOP-BANG Score = Sum of Yes answers (0-8) S: Snoring (loud) → 1 point T: Tired/Sleepy during day → 1 point O: Observed stop breathing → 1 point P: Blood Pressure (treated) → 1 point B: BMI > 35 → 1 point A: Age > 50 → 1 point N: Neck > 40 cm → 1 point G: Gender (Male) → 1 point

Example Calculation

Result: STOP-BANG = 5 — High risk for moderate-to-severe OSA

Five out of eight criteria met (snoring, tiredness, BMI > 35, age > 50, male gender). This places the patient in the high-risk category with high probability of moderate-to-severe OSA. Formal polysomnography is recommended, and perioperative precautions should be taken if surgery is planned.

Tips & Best Practices

Practical Guidance

Use consistent units, verify assumptions, and document conversion standards for repeatable outcomes.

Common Pitfalls

Most mistakes come from mixed standards, rounding too early, or misread labels. Recheck final values before use. ## Practical Notes

Use this for repeatability, keep assumptions explicit. ## Practical Notes

Track units and conversion paths before applying the result. ## Practical Notes

Use this note as a quick practical validation checkpoint. ## Practical Notes

Keep this guidance aligned to expected inputs. ## Practical Notes

Use as a sanity check against edge-case outputs. ## Practical Notes

Capture likely mistakes before publishing this value. ## Practical Notes

Document expected ranges when sharing results.

Frequently Asked Questions

A score of 3 seems very common — does everyone have OSA?

A STOP-BANG ≥ 3 has high sensitivity (93%) but low specificity (36%), meaning it correctly identifies most people with OSA but also flags many who do not have it. This is appropriate for a screening tool — it casts a wide net. The formal diagnosis still requires polysomnography.

Can women have OSA despite the G (male gender) criterion?

Absolutely. Women can score up to 7 on the other criteria. OSA is underdiagnosed in women because they often present differently — with insomnia, morning headaches, and fatigue rather than classic loud snoring. The male gender criterion reflects the 2:1 male predominance, not exclusivity.

What happens during a polysomnography (sleep study)?

An overnight sleep study (PSG) monitors brain waves (EEG), eye movements, muscle tone, airflow, respiratory effort, oxygen saturation, heart rhythm, and body position during sleep. It determines the Apnea-Hypopnea Index (AHI) — the number of breathing disturbances per hour — which defines OSA severity.

How does STOP-BANG compare to Epworth Sleepiness Scale?

Epworth measures daytime sleepiness specifically and has lower sensitivity for OSA than STOP-BANG. STOP-BANG is preferred for OSA screening because it includes demographic and anthropometric risk factors. Epworth is useful for monitoring treatment response and assessing hypersomnolence from any cause.

Why is neck circumference included?

Large neck circumference (> 40 cm / 16 inches) indicates increased soft tissue around the airway, which predisposes to airway collapse during sleep. It is an independent risk factor for OSA even after controlling for BMI, making it a uniquely informative screening criterion.

What are the perioperative risks of undiagnosed OSA?

Patients with OSA have 2-3× higher rates of postoperative respiratory complications, cardiac events, ICU transfers, and difficult intubation. Opioid sensitivity is increased, and postoperative desaturation is common. Enhanced monitoring and judicious opioid use are critical.

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