What is the DSQ-Brief?

The DSQ-Brief is a 4-item screening scale for ME/CFS developed by Jason and colleagues at DePaul University in 2023. It assesses fatigue and post-exertional malaise, the two hallmark features of ME/CFS. In validation it achieved 96% accuracy against healthy controls, with 94% sensitivity and 98% specificity.

Does a positive DSQ-Brief screen mean I have ME/CFS?

No. A positive screen means your responses match the symptom pattern the tool looks for. It is not a diagnosis. Its accuracy also drops to around 82 to 84 percent when distinguishing ME/CFS from other fatiguing conditions such as long COVID or multiple sclerosis, which is why the full DSQ-2 is more informative. Discuss any result with your doctor.

How is the DSQ-Brief scored?

Each of the four symptoms is rated for frequency and severity over the past six months, each from 0 to 4. A symptom counts as present when both frequency and severity are rated 2 or higher. The screen is positive when all four symptoms meet this threshold.

Tools

ME/CFS screening questionnaire

The DSQ-Brief: a 4-item self-check

This is a free, interactive version of the DSQ-Brief, a short screening scale for myalgic encephalomyelitis / chronic fatigue syndrome (ME/CFS) developed by Leonard Jason and colleagues at DePaul University and published in 2023. It was drawn from the much longer DePaul Symptom Questionnaire and distilled down to the four items that best separate people with ME/CFS from those without it.

Those four items assess the two hallmark features of ME/CFS: fatigue and post-exertional malaise — the disproportionate worsening of symptoms after even minor physical or mental effort. In the validation study of 3,427 people, this 4-item screen achieved 96% accuracy against healthy controls, with 94% sensitivity and 98% specificity.

It is intended for anyone with persistent fatigue, a post-viral illness, or suspected ME/CFS who wants a quick, structured self-check before deciding whether to look into things further. It takes under two minutes. Answer each item for how it has been over the past six months, and you will get an immediate result with a per-symptom breakdown. No sign-up or email is required, and nothing you enter leaves your device.

This is not a diagnostic tool. A screening result reflects self-reported symptoms and is not a diagnosis of ME/CFS or any other condition. The DSQ-Brief is very good at telling ME/CFS apart from health, but less so from other fatiguing illnesses, so a result here is a starting point for a conversation with your doctor, not a conclusion. Based on: Jason LA, Benner S, Furst J, Cathey P. Developing and validating a brief screening scale for ME/CFS. Fatigue: Biomedicine, Health & Behavior. 2023.

For each symptom, rate how often you have had it and how severe it has been, over the past six months.

Your DSQ-Brief result

Symptom breakdown

Symptom	Frequency	Severity	Score	Threshold

Score is a 0–100 composite: (frequency + severity) ÷ 2 × 25. The threshold column shows whether the symptom met the 2/2 rule (both frequency and severity rated 2 or higher).

Why the full questionnaire matters

The DSQ-Brief screens for the core features of ME/CFS — fatigue and post-exertional malaise — and it does that well: 96% accuracy against healthy controls. Its accuracy drops to around 82–84%, though, when the task is telling ME/CFS apart from other conditions that also cause fatigue, such as long COVID, multiple sclerosis, or post-polio syndrome. Four questions can only tell you so much.

The full DePaul Symptom Questionnaire (DSQ-2) captures symptoms across eight domains — including orthostatic intolerance, cognitive impairment, pain, sleep disruption, and immune and temperature symptoms — that together build a far more complete picture. In validation studies the full questionnaire held 93–94% accuracy even against other chronic illnesses, and it screens your answers against the four major ME/CFS case definitions.

If you have 10–15 minutes, the full version gives you a detailed domain-by-domain breakdown you can take to a clinical appointment.

Take the full DSQ-2 questionnaire →

Understanding your result

This screen looks at four symptoms only. A positive result means all four were reported at a frequency and severity consistent with the pattern seen in ME/CFS in the validation study. It is not a diagnosis, and a negative result does not rule ME/CFS out — the four items here are deliberately narrow.

Post-exertional malaise, in particular, is the feature that most distinguishes ME/CFS from ordinary fatigue or deconditioning. If your symptoms clearly worsen in the hours or days after activity that used to be manageable, that is worth raising with a clinician regardless of the number this tool produces.

This result is not a diagnosis. It reflects what you have reported about your own symptoms. Discuss it with your doctor or specialist.