Introduction: In 1190, the American College of Rheumatology introduced guidelines for the diagnosis of giant cell arteritis. According to their classification scheme, a positive diagnosis is made if three out of five possible criteria are present these criteria include age greater than 50, new headache, temporal artery abnormality, elevated ESR or abnormal temporal artery biopsy. Since that time, there have been conflicting reports in the literature regarding the need for confirmatory temporal artery biopsy. In this study, we retrospectively reviewed 114 cases of suspected giant cell arthritis, which were referred for temporal artery biopsy. ACR criteria were compared the outcome of temporal artery biopsy.

Methods: A retrospective review of all patients (n=114) undergoing temporary biopsy for suspected GCA between 2006 and 2016 was completed. Data collected included biopsy results, ESR, CRP, age, and symptoms. Patients were separated into three groups based on biopsy results: positive, inconclusive or negative. Biopsy outcomes were analyzed with regarding ACR criteria for GCA. Pretest and posttest probabilities were assessed.

Results: Out of 114 patients 4 were considered inconclusive, 109 had negative biopsies, and 9 were positive. The ACR criteria only had a sensitivity of 0.66, specificity of 0.38 and a positive predictive value of 0.08 in predicting the outcome of the temporal artery biopsy. The negative predictive value of the ACR criteria was 0.975. The negative predictive value of ESR alone was 0.97.

Conclusions: Despite low pretest probabilities and positive predictive value, the ACR criteria showed a 97.5% negative predictive value and ESR alone showed a 97% negative predictive value. Hence, the necessity of a temporal artery biopsy in the absence of an ESR <50 should be questioned.

Patient Care: Our research can help identify patients who are in need of a temporal artery biopsy and those patients who can be treated for giant cell arteritis without a biopsy.

Learning Objectives: By the conclusion of this session, participants should be able to: diagnose giant cell arteritis based on diagnostic criteria Understand alternative diagnostic modalities for temporal arteritis. Compare the accuracy of temporal artery biopsy with the accuracy of clinical criteria

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