Purpose

Giant cell arteritis (GCA) is a sight-threatening vasculitis requiring rapid diagnosis and treatment. Temporal artery biopsy (TAB) has traditionally been the gold standard for diagnosis, with ultrasound (US) emerging as a non-invasive alternative, however real-world performance remains uncertain. This study evaluates the utility of TAB, US, and clinical features in diagnosing GCA, with a focus on identifying practice-changing insights.

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Methods

We conducted a retrospective study of 41 patients who underwent both TAB and US for suspected GCA over 10 years at a single centre. A final clinical diagnosis of GCA was the reference standard. Data collected included age, systemic and ocular symptoms, visual acuity and colour vision, outcomes of TAB/US, C-reactive protein (CRP) and erythrocyte sedimentation rate (ESR) levels. We calculated diagnostic accuracy metrics and performed univariate logistic regression to identify clinical predictors for GCA.

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Results

21 of 41 patients (51.2%) were clinically diagnosed as GCA. TAB demonstrated a sensitivity of 38.1% and specificity of 100%, while US sensitivity was 19.0% and specificity 100%. Combined testing improved sensitivity to 47.6%. Notably, 52.4% with diagnosed GCA had negative results on both tests representing a substantial false negative burden. Agreement between modalities was limited (κ = 0.23). Longer steroid exposure prior to biopsy was associated with reduced TAB positivity. Increasing age and elevated CRP and ESR were significant predictors of GCA.

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Conclusion

In our cohort, TAB/US showed excellent specificity but substantially lower sensitivity than landmark studies. Over half of clinically diagnosed GCA cases were missed on TAB/US despite combined testing, and poor agreement suggests each test may detect different disease phenotypes. In real world practice, TAB and US are therefore useful rule-in tests but lack sufficient sensitivity to exclude GCA. These results challenge reliance on investigative pathways alone and support a shift towards clinically-driven, multimodal diagnostic strategies to avoid treatment delay in high-risk patients.

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Additional Authors

First name	Last name	Base Hospital / Institution
Nicole	Quah	Whipps Cross Hospital, Barts Health NHS Trust
Prachi	Shah	Moorfields Eye Hospital
Ian	Subak-Sharpe	Whipps Cross Hospital, Barts Health NHS Trust

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