How does pre-biopsy steroids affect TAB?

TAB sensitivity decreases after 2-4 weeks of steroid therapy. Biopsy within 2 weeks of starting steroids maintains reasonable sensitivity. Starting steroids must not be delayed for biopsy in patients at high vision risk.

What segment length is needed for TAB?

Minimum 1.5-2 cm segment is recommended. Skip lesions mean a negative biopsy does not exclude GCA; sensitivity increases with longer segments and contralateral biopsy if first is negative.

What are skip lesions in GCA?

Skip lesions are normal segments interspersed between inflamed segments in the temporal artery. They explain the 20-25% false-negative rate of TAB and the need for adequate segment length.

GCA Temporal Artery Biopsy Sensitivity Estimator

Estimate temporal artery biopsy (TAB) sensitivity for giant cell arteritis (GCA). Sensitivity is 75-80% for cranial GCA and lower for large-vessel GCA. Segment length, skip lesions, and pre-biopsy steroids affect yield.

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