Rate of Discordant Findings in Bilateral Temporal Artery Biopsy to Diagnose Giant Cell Arteritis

OBJECTIVE: To determine to what extent performing simultaneous bilateral temporal artery biopsies might increase the diagnostic sensitivity in giant cell arteritis (GCA). METHODS: In total 173 consecutive pathology reports of temporal artery biopsies were reviewed for histological findings by a single pathologist. The rate of discordance of biopsy results was calculated in patients with GCA. RESULTS: Biopsies were performed bilaterally and simultaneously in 132 cases; 51 had positive results. In 38 the biopsy was positive on both sides (concordant results), while in 13 patients only one side was positive (discordant results), reaching a discordance rate of 13/51=0.255. Therefore 12.7% of the patients (one-half of the discordance rate) could have been misdiagnosed as biopsy-negative had a biopsy been done only unilaterally in those 51 cases. CONCLUSION: These data suggest that performing bilateral temporal artery biopsies increases the diagnostic sensitivity of the procedure by up to 12.7%, compared to unilateral biopsies.