Table 1.

The American College of Rheumatology (ACR) classification criteria for GCA.

(i)Age at disease onset >50 years: development of symptoms or findings beginning at the age of >50 years. (ii)New headache: new onset of or new type of localized pain in the head. (iii)Temporal artery abnormality: temporal artery tenderness to palpation or decreased pulsation, unrelated to arteriosclerosis of cervical arteries. (iv)Elevated ESR: ESR55 mm/hour by the Westergren method. (v)Abnormal artery biopsy: biopsy specimen with artery showing vasculitis characterized by a predominance of mononuclear cell infiltration or granulomatous inflammation, usually with multinucleated giant cells.

For purposes of classification, a patient shall be said to have GCA (TA) if at least three of these five criteria are present. The presence of any three or more criteria yields a sensitivity of 93.5% and a specificity of 91.2%.