A blood pressure measurement system comprising: a heart reference sensor (HRS) including a bladder for mounting proximate the patient's heart level, tubing, and a pressure sensor； a finger cuff attachable to a patient's finger； and a blood pressure measurement controller coupled to the HRS and the finger cuff to perform blood pressure measurement functions. The pressure sensor is located at approximately the same height level of the finger cuff and the tubing extends from the bladder of the HRS to the pressure sensor, the bladder of the HRS including liquid in fluid communication with liquid in the tubing connected to the pressure sensor at the patient's finger level such that gravity generated pressure differences between the patient's heart level and finger level are measurable by the pressure sensor of the HRS to be subtracted from the blood pressure measurement, wherein the tubing is non-plasticized tubing or chemically inert tubing.
