Aims It is a standard practice to examine multiple levels of needle core biopsies taken for mammographic calcification, but there is almost no evidence on the value of levels in core biopsies taken for other reasons. This study aimed to assess the value of levels for needle core biopsies taken for investigation of lesions other than calcification. A secondary aim was to assess interobserver agreement of diagnosis.

Methods For each of the 375 breast core biopsies with three levels the first level was reviewed and a diagnosis made. Then levels 2 and 3 were reviewed and a final diagnosis was made.

Results The diagnosis after examining three levels was different from that in the initial level in 4 of 272 (1.5%, 95% CI 0.04% to 3%) core biopsies taken for reasons other than calcification and in 13 of 103 (13%, 95% CI 6% to 19%) biopsies taken for investigation of calcification. Interobserver agreement of the original diagnosis at the time of reporting and the final diagnosis at the review for this study was 96% (κ 0.947).

Conclusions This study confirms the value of levels of biopsies taken to investigate mammographic calcification, but suggests that routine levels are of limited value for breast core biopsies taken for other reasons.