Stop Bang Score Calculator

STOP-BANG is a screening instrument, not a diagnostic one, and its design reflects that purpose: it is deliberately tuned for high sensitivity at the cost of specificity, so that few people with significant obstructive sleep apnea are missed even though many who screen positive will turn out not to have it. The eight yes or no items split into a symptom half and an anthropometric half. STOP covers loud Snoring, daytime Tiredness, Observed apneas or choking during sleep, and treated high blood Pressure. BANG covers BMI above 35 kg per square meter, Age over 50, Neck circumference above 40 cm, and male Gender. Each scores one point, giving a range of 0 to 8. The physiologic rationale is that upper airway collapsibility rises with pharyngeal fat deposition, age-related loss of dilator muscle tone, and the longer male airway, while nocturnal hypoxia and sympathetic surges drive the hypertension captured by the P item. Interpretation is anchored to the apnea-hypopnea index measured by polysomnography, where 5 to 15 events per hour is mild, 15 to 30 moderate, and above 30 severe. A score of 0 to 2 gives a negative predictive value near 90 percent for moderate-to-severe disease. Scores of 3 to 4 are intermediate, and 5 to 8 confer high probability, with sensitivity for severe apnea approaching 100 percent at a threshold of 3 but specificity falling to roughly 25 to 40 percent. The main limitations are poor specificity in obese surgical populations, reliance on a bed partner for the observed-apnea item, and undercounting in women, whose apnea more often presents as insomnia and fatigue than as witnessed snoring.

The questionnaire was developed by Frances Chung and colleagues in the Department of Anesthesia at the University Health Network, Toronto Western Hospital, University of Toronto. The problem they were addressing was specifically perioperative: undiagnosed obstructive sleep apnea markedly increases the risk of difficult airway management, postoperative respiratory depression from opioids and sedatives, and unplanned intensive care admission, yet preoperative clinics had no practical way to screen the large volume of patients passing through. Existing tools were unsuited to the setting, since the Berlin Questionnaire was long and the Epworth Sleepiness Scale measures subjective sleepiness rather than apnea risk. Chung's group derived and validated the four-item STOP questionnaire in surgical patients and published it in Anesthesiology in 2008, then showed that adding the four demographic and anthropometric BANG items substantially improved sensitivity for moderate and severe disease. Validation was against attended polysomnography in surgical patients, with later studies extending it to sleep clinic, primary care, and general population samples. Meta-analyses published through the 2010s consistently reported sensitivity above 90 percent for moderate-to-severe apnea at a cut-off of 3. The Society of Anesthesia and Sleep Medicine issued guidelines in 2016 recommending preoperative screening with a validated tool, and STOP-BANG became the most widely used option internationally, translated into many languages and incorporated into preoperative assessment protocols and commercial driver medical examinations.