Temporal artery biopsy for giant cell arteritis.

OBJECTIVE: To evaluate the influence of temporal artery biopsy (TAB) techniques on establishing a diagnosis of giant cell arteritis (GCA).

METHODS: A retrospective review of 141 TAB pathology records from 1996 to 2002 was conducted. Histopathology slides on 136 TAB were reviewed by a single, independent, blinded pathologist.

RESULTS: The population included 101 (71.6%) women, mean age 75.8 years (range 45-92), and 40 men, mean age 73.9 years (range 47-90). The mean length of a TAB sample after formalin fixation was 1.76 cm (range 0.1-5.3). Surgeons performing the TAB represented 6 disciplines. Ophthalmologists had the largest volume, at 78 biopsies (55.3%), and the longest segments of artery, with a mean length of 2.37 cm (range 0.4-5.3) (p < 0.001). Comparison of biopsy interpretation provided a kappa coefficient of 0.8 (95% CI 0.69, 0.91). The 38 (27%) positive biopsies had a mean length of 2.07 cm (SD 1.1), and the 98 negative biopsies a mean length of 1.69 cm (SD 1.04) (p = 0.058). Biopsies < 1.0 cm length (n = 35, 25.7%) were less likely to be positive than those > or = 1.0 cm (p = 0.037). No significant differences in surgical discipline, hospital site, number of slides, or cross-sections/cm artery were found between the positive and negative biopsies.

CONCLUSION: Biopsy specimens reported positive for GCA tended to be longer than those reported as negative. A "threshold" size of 1.0 cm is associated with increased diagnostic yield. Lack of standardization of biopsy harvesting and processing techniques may contribute to variable sensitivity of TAB.