Patients with cluster headache often report a long diagnostic delay. This study creates and validates a screening test that could help speed up the diagnostic process. We invited patients to enrol in this diagnostic case–control study if a trigeminal autonomic headache had been suspected or confirmed. Patients in whom the diagnosis of a cluster headache was not made were controls. First, all participants answered 22 diagnostic questions with “yes” or “no”. Next, we eliminated questions that did not distinguish well between the groups. Then, the variables entered a regression model with the headache diagnosis as the dependent variable. Finally, we combined the remaining variables into a diagnostic scale and tested its accuracy. Seventy-four patients participated, 45 of whom suffered from a cluster headache. The analyses identified five questions distinguishing cluster headache patients and controls. These addressed smoking, being awakened by the pain, restlessness during the attack, unilateral tearing, and duration of the attack (hence, the “SMARTED” scale). The area under the ROC curve was 0.938; sensitivity and specificity, the positive and negative predictive values were 98%, 65%, 81% and 94%, respectively. The SMARTED scale validly and accurately screens for cluster headache in patients suspected of a trigeminal autonomic headache.