Reasons for a negative temporal artery biopsy:
(1) The process is not involving a temporal artery.
(2) The surgeon selected a suboptimal biopsy site (for example,taking the biopsy from the asymptomatic side).
(3) The surgeon took too small a biopsy.
(4) The surgeon biopsied a pulsatile artery rather than one that is not (a nodular, pulseless artery is more likely to show involvement).
(4) The arterial involvement is patchy, with "skip" lesions that may be missed.
(5) There was a failure in pathologic processing (inadequate sectioning of the specimen)
(6) The pathologist failed to recognize a focus of inflammation.
where:
• Use of Doppler ultrasonography might be helpful in finding an involved segment.
Adequate pathologic processing involves:
(1) making relatively thin cross sections of the artery
(2) taking multiple levels of each block
(3) using appropriate stains to enhance detection of inflammatory cells
