Is temporal artery biopsy essential in all cases of suspected giant cell arteritis?

Objective. Temporal artery biopsy (TAB) is performed in cases of suspected giant cell arteritis (GCA), and is the gold-standard for diagnosis of the disease. Current American College of Rheumatology (ACR) classification criteria may aid in the diagnosis of GCA. We aimed to assess whether TAB is essential in all cases of suspected GCA, or whether ACR criteria can replace the need for this procedure in some cases. Methods. Retrospective analysis of 216 patients who underwent TAB in a single hospital between 2000 and 2013. Pre-TAB and post-TAB ACR criteria were calculated. Sensitivity and specificity of ACR criteria for the diagnosis of GCA were assessed. Results. Overall, 55 patients had histological evidence of GCA. Out of 161 patients with negative TAB findings, 34 were diagnosed with GCA, and 127 were not diagnosed with GCA. Sensitivity of TAB for the diagnosis of GCA was 61.7%. Sensitivity and specificity of ACR criteria for diagnosis of GCA before performing TAB were 68.5% and 58%, respectively. Sensitivity and specificity of ACR criteria after performing TAB biopsy were 89.8% and 64.5%, respectively. Conclusion. Temporal artery biopsy should be performed in the majority of patients with suspected GCA, and may be obviated only in patients with a pre-TAB ACR score of <= 1. In all other cases, when GCA is suspected, ACR criteria should not be a substitute to TAB, as they are not highly specific.