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CPAP Clarity

NoSAS Score

Five quick facts about you, scored the way the NoSAS authors published, to see whether a sleep apnea conversation with your doctor makes sense.

years
What sex were you assigned at birth?

The score was built on sex recorded as male or female in the study.

Do you snore?

If nobody has told you either way, pick Not sure and we will show the score both ways.

in

Measure around your neck with a soft tape.

Body mass index (BMI)

Type 0 inches if your height is an exact number of feet.

Still needed: age, sex, snoring, neck size, height and weight.

What This Tool Does

The NoSAS score adds up points for five things a doctor can check in a minute: neck size, body mass index (BMI), snoring, age and sex. The total runs from 0 to 17. Its authors found that people scoring 8 or more were more likely to have clinically significant sleep-disordered breathing, the group of conditions that includes obstructive sleep apnea. The questions above are written in our own words; the points and the cutoff are exactly as published.

Where the Score Comes From

The score was built by a team at Lausanne University Hospital in Switzerland and published in The Lancet Respiratory Medicine in 2016 (Marti-Soler and colleagues). They used 2,121 adults aged 40 to 85 from HypnoLaus, a population study in which participants had a clinical check-up and a full overnight sleep recording at home, and looked for the simplest set of facts that picked out people with clinically significant sleep-disordered breathing.

They then tested the score on a separate group in Brazil, the EPISONO cohort in São Paulo (adults aged 20 to 80). Its ability to separate people with and without the condition, measured as the area under the curve, was 0.74 in the Swiss group and 0.81 in the Brazilian one. In the same Swiss data, STOP-Bang scored 0.67 and the Berlin questionnaire 0.63.

Two limits are worth knowing. The score gives no points for symptoms such as breathing pauses someone has seen or heavy daytime sleepiness, so a low score can miss a person whose warning signs are symptoms rather than body measurements. And it was designed to help decide who to test, not to replace the test.

How the Points Add Up

  • A neck of more than 40 cm (about 15.7 in) adds 4 points. Exactly 40 cm adds nothing.
  • A BMI of 25 to under 30 adds 3 points, and a BMI of 30 or more adds 5.
  • Snoring adds 2 points.
  • Being older than 55 adds 4 points. Age 55 itself adds nothing.
  • Being male adds 2 points.

A total of 8 or more is at or above the published cutoff. We round your neck size and BMI to one decimal place and score that rounded value, so the number you see is the number that counted.

Before You See Your Doctor

Bring your total and the list of what counted. If you scored 8 or more, or you have symptoms whatever your score, it is worth asking whether a sleep test makes sense for you; many people can now be tested at home. If you did not know whether you snore, ask someone who has heard you sleep before the appointment, because that answer alone can move the score across the cutoff.

Frequently Asked Questions

What is a normal NoSAS score?

The NoSAS score runs from 0 to 17. Its authors used 8 points or more as the cutoff for a higher chance of clinically significant sleep-disordered breathing, so a score of 0 to 7 is below that cutoff and 8 to 17 is at or above it. A score under 8 does not rule sleep apnea out, and a score of 8 or more does not mean you have it.

How many points does each NoSAS factor add?

A neck circumference of more than 40 cm adds 4 points. A BMI of 25 to under 30 adds 3, and a BMI of 30 or more adds 5. Snoring adds 2, being older than 55 adds 4, and being male adds 2. The maximum is 17.

Is the NoSAS score better than STOP-Bang?

In the 2016 paper that introduced it, the NoSAS score separated people with and without clinically significant sleep-disordered breathing better than STOP-Bang and the Berlin questionnaire in the authors' Swiss cohort. That comparison came from the authors' own study groups, so it is one result, not a final ranking. Any of these screeners is a reason to talk to a doctor, not a substitute for a sleep test.

Does a high NoSAS score mean I have sleep apnea?

No. The NoSAS score estimates who is more likely to have sleep-disordered breathing so that a doctor can decide who to test. Only an overnight sleep test, read by a clinician, can diagnose sleep apnea. If your score is 8 or more, it is worth discussing with your doctor, who may suggest a home or in-lab sleep test.

I already use CPAP. Is the NoSAS score useful for me?

Not very. The NoSAS score is for people who have not been tested. If you are already diagnosed and using CPAP, your machine's own data says far more about how therapy is going than a screening score can. You can import your SD card on the CPAP Clarity home page to see it.

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