Hand-held shirt-pocket portable instrument for quantitative measurement of glucose or analysis in biological fluids. The system accepts a disposable diagnostic reagent test device which has a reagent carrier and mode of identifying to the instrument the reagent lot characteristics. The instrument includes a housing structure having a visual LCD readout, a microprocessor, and photosensing circuitry which measures the change of color of the reagent carrier upon reaction in the reacting chemistry of the disposable test device. The housing also includes a spring arrangement for actuating a disposable lancet into the skin for generating blood. The disposable diagnostic reagent unit includes a configuration for transporting of the blood in the regent unit. The system includes verification and calibration sequences for the electronics, the chemistry of an unused disposable unit, the presence of a blood sample, and the ambient temperature. The system also provides for storing a plurality of analysis readings.