Temporal artery biopsy: is there any value in examining biopsies at multiple levels?

Aims-To analyse the cost-effectiveness of three strategies for examining te mporal artery biopsies based on data from cases examined over the past 10 y ears. Methods-Of a total of 172 temporal artery biopsies, five were unsuitable fo r further analysis, 47 had already had levels cut, and 120 had levels cut a s part of the study. All the biopsies were examined blind before and after levels. A tree with eventual diagnostic outcomes for different strategies w as constructed and economic and sensitivity analyses performed. Welcan unit s were used to assess technical workload. Results-Only one of the 132 initially normal cases and two of 14 diagnosed with periarterial lymphocytic infiltration (PALI) revealed giant cell arter itis after examining the tissue at multiple levels. Fifteen cases (8.9%) sh owed PALI not previously observed. The marginal cost for each extra case of giant cell arteritis detected was 83.5 Welcan units for a strategy of rout ine levels on all sections, and 21 Welcan units for a strategy of only cutt ing levels if PALI was present on the initial section. These costs were sen sitive to the frequency of giant cell arteritis in cases with PALI and to t he relative extra cost of moving from cutting single section to routine lev els. Conclusions-Routinely examining a temporal artery biopsy at multiple levels does not increase the diagnostic field of the test, although selective fur ther examination may be indicated in some cases. The significance of PALI i s uncertain. The cost-benefit of the different strategies in terms of clini cal decision. making revolve around the perceived risk inherent in not maki ng a diagnosis of giant cell arteritis.