A biopsy system comprises a biopsy device, a fluid canister, and an auxiliary vacuum source. The biopsy device comprises a body, a needle, a hollow cutter, and a primary vacuum pump. The primary vacuum pump is operable to induce a vacuum in the lumen of the cutter. The fluid canister is configured to receive liquids communicated proximally through the cutter lumen. The auxiliary vacuum source is operable to induce a vacuum in the cutter lumen, thus supplementing the primary vacuum pump. The auxiliary vacuum source may be coupled directly with the fluid canister, such that the fluid canister is positioned along the fluid path between the auxiliary vacuum source and the biopsy device. The biopsy device may further include an integral tissue sample holder. The cutter lumen, the primary vacuum pump, the fluid canister, and the auxiliary vacuum source are all in fluid communication with the tissue sample holder.