Temporal artery ultrasound versus temporal artery biopsy for giant cell arteritis

This is a protocol for a Cochrane Review (Diagnostic test accuracy). The objectives are as follows:. To determine the diagnostic accuracy of the 'halo sign' on temporal artery ultrasound in people with suspected GCA, using the ACR 1990 Classification as a reference standard. We will consider two tests:. triage test before temporal artery biopsy, if temporal artery biopsy is considered: a sensitivity of at least 95% with a minimum specificity of 50% will be required to rule out GCA and avoid biopsy in patients who test positive; a specificity of 95% and a sensitivity of 50% will be required to rule in GCA and refer for biopsy patients who test negative. replacement of temporal artery biopsy as one of the ACR 1990 criteria: this will be achieved if ultrasound shows sensitivity and specificity similar to biopsy.