The instrument has an exchangeable test tape cartridge including a test tape, which includes test elements loaded with bodily fluids e.g. blood. A tape drive is coupled with the test tape cartridge and pre-winds the test tape such that the test elements are successively provided at application points. The tape drive includes a reduction gear (28), which is arranged between a direct current motor (26) i.e. mechanically commutated motor, and the cartridge. A rotor of the motor includes a bearing point arranged in a drive housing.
