# Temporal Artery Biopsies: Understanding the Low Positivity Rate

## TL;DR

Temporal artery biopsies have a low positivity rate for giant cell arteritis, and the study identifies factors influencing biopsy results and clinical diagnosis discrepancies.

## Contribution

The study identifies factors associated with positive biopsy results and proposes refinements to improve diagnostic accuracy for giant cell arteritis.

## Key findings

- Temporal artery biopsy positivity rate was 16.6% in the study.
- General health deterioration was significantly associated with positive biopsy results.
- Clinical diagnoses by referring physicians often differed from biopsy results.

## Abstract

Objective

We compared the yield of temporal artery biopsies with the clinical diagnoses made by referring physicians and determined the factors associated with a positive biopsy.

Methods

This is a monocentric, retrospective analytical study of patients treated between January 2021 and December 2024 who underwent temporal artery biopsy for suspected giant cell arteritis. The primary endpoint was the biopsy positivity rate. We also studied patient-related factors, symptoms, and clinical variables, including surgical and pathological factors, to identify those associated with a positive biopsy result.

Results

The study included 72 patients (40 females, 32 males). General health deterioration (OR = 3.71, p = 0.05) was significantly associated with a positive biopsy in the univariate analysis. The average length of the biopsy specimen after fixation was 13.4 mm. The positivity rate of temporal artery biopsies was 16.6% (n=12), while in 55.5% of cases (n=40), referring physicians ultimately diagnosed typical isolated Horton’s disease (n=29, 40.2%) or isolated Horton’s disease associated (n=10, 13.8%) with pseudo-polyarthritis rheumatica.

Conclusion

The anatomic-clinical discordance highlighted in our study supports findings from the literature. This can be explained by factors related to the pathology itself but also by a proactive diagnostic approach and variability in performing the surgical procedure. We have proposed avenues to refine the indications for this procedure and improve the performance of our technique. Temporal artery biopsy should be reserved for well-supported suspicions of Horton’s disease. Sampling upstream from the bifurcation of the superficial temporal artery appears to offer the best reproducibility.