A biofluid drop ejection unit for ejecting biofluid drops. A biofluid drop ejection mechanism of such a unit includes a transducer, which generates energy used to emit the biofluid drop. Further provided is a reagent cartridge or biofluid containment area which holds the biofluid. The reagent cartridge or biofluid containment area is configured to hold low volumes of biofluid and to avoid contamination of the biofluid. The reagent cartridge or biofluid containment area is in operational connection with the drop ejection mechanism such that upon operation of the drop ejection mechanism, biofluid drops are emitted. The biofluid drop ejection mechanism is a high efficiency device, and may be configured as two separate pieces or as a single disposable unit.