Can one have a normal ESR with temporal arteritis?

As one could probably guess by the question itself, the answer is yes. For some reason, I thought that ESR was a super sensitive test but as it turns out its not as good as I perceived.

Retrospective study by Parikh et al. noted that sensitivity of elevated ESR was 76-86% (not 100%) and elevated CRP was 97.5%. Together, sensitivity was 99%. Of note, normal ESR value dependent on age and sex; normal CRP value independent of these factors.

Take home point: in patient with high pretest probability of temporal arteritis ie > 50 years old, with new onset of localized headache, temporal artery tenderness, abrupt onset of visual disturbances, jaw claudication (jaw hurts with eating) and polymyalgia rheumatica (aching and morning stiffness in the shoulders, hips, neck and torso); even if ESR is normal, consider checking CRP +/- temporal artery biopsy.

Source

Parikh, Mona, et al. "Prevalence of a Normal C-Reactive Protein with an Elevated Erythrocyte Sedimentation Rate in Biopsy-Proven Giant Cell Arteritis." Opthalmology v 113, October 2006, pgs 1842-1845.