For some procedure codes, particularly for IHC codes, we could not distinguish between diagnostic and predictive biomarker testing (ie, IHC staining for TTF-1 or p40 vs IHC staining for PD-L1 or ALK in NSCLC) or identify instances where pathologists billed for codes different from the assays performed. Here, TTF1 is linked to non-small cell lung carcinoma.