Clinical reference · Card 01 of 11 · Screening
The ETCH screen — three questions
Erwin Test for Cluster Headache. Ask all three questions, verbatim — the validation used these exact words.
1
Is this the worst pain you have ever experienced?Alone: sensitivity 0.94 (0.85–0.98), specificity 0.53 (0.44–0.60). Highly sensitive, poorly specific.
2
Does your pain last less than 4 hours?4 hours, not 3 — the validated cut-off. It separates cluster headache from migraine (4–72 h).
3
Do one or more of these occur during the headache: unilateral red eye, unilateral lacrimation, unilateral rhinorrhoea, or unilateral nasal congestion?Cranial autonomic features, same side as the pain.
YES TO ALL THREEn=224, headache-centre cohort
84%Sensitivity95% CI 73–92
89%Specificity95% CI 84–94
76%Positive predictive value95% CI 64–85
93%Negative predictive value95% CI 88–97
A screen, not a diagnosis. Confirm against ICHD-3 3.1 criteria (Card 02) and exclude red flags (Card 04). Validated in a specialist population — performance in unselected primary care is untested.
SOURCES Parakramaweera R, Evans RW, Schor LI, et al. Cephalalgia 2021;41(13):1298–1309. doi:10.1177/03331024211018138. PMID 34148408. Questionnaire © 2020 UTHealth Houston, CC BY-NC-ND 4.0.
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