Which clinical features and lab findings increase the likelihood of temporal arteritis?

Testing for thrombocytosis more helpful than ESR

Lab tests using ESR have been examined in various studies. A high ESR (>100 mm/hour) may only slightly increase the chance of temporal arteritis (TABLE). Five studies³ have documented that thrombocytosis (platelets >375,000/mm³) is more helpful for ruling in temporal arteritis than an elevated ESR.⁴ Conversely, normal platelets are more accurate for ruling out temporal arteritis than a normal ESR.

Recommendations from others

According to the American College of Rheumatology, a patient is said to have temporal arteritis when 3 of the following 5 criteria are met:

• age of onset ≥50 years of age
• new onset of localized headache
• temporal artery tenderness or decreased pulsation
• ESR >50 mm/hour
• abnormal artery biopsy.^5,6