A method of controlling lancing speed of a lancing structure of a portable handheld medical diagnostic device includes providing an elongated lancet structure having a skin piercing end and a blood transport portion adjacent the skin piercing end. The skin piercing end when displaced makes an incision at a skin site to produce an amount of bodily fluid from the skin site and in which the blood transport portion transports the amount of bodily fluid away from the skin site for use by a measurement system in making a physiological measurement. A spring-driven motor assembly is operatively connected to the lancet structure. The spring-driven motor assembly displaces the lancet structure toward the skin site to make the incision for producing the amount of bodily fluid and retracts the lancet structure to carry the amount of bodily fluid away from the skin cite. A speed control mechanism is engaged with the spring-driven motor assembly as the spring-driven motor assembly retracts the lancet structure thereby decelerating the lancet structure as the lancet structure is retracted away from the skin site.
