The bulk of the cost of the BLN assay is the cost of consumables (ie, the assay kit). Use of in-house reagents would reduce this to <£50 per patient, and the overall cost to £129, comparable with frozen section or imprint cytology. Assumptions include the requirement for 1 h of biomedical scientist time per patient. Pathologist time is likely to be greater for frozen section and imprint cytology, estimated as 45 min per patient (including reporting and time in the operating theatre) compared with 10 min per patient for the BLN assay. Equipment and servicing costs are most significant for the BLN assay. Frozen section and imprint cytology costs do not include immunohistochemistry, which would add around £25 to the consumables required.