Disclosed is a system to monitor a finger cuff connectable to a patient's finger to be used in measuring the patient's blood pressure by a blood pressure measurement system utilizing the volume clamp method and to measure the plethysmogram of the finger cuff. The system comprises the finger cuff that includes an enclosing portion that encloses a patient's finger. The enclosing portion includes a bladder and a light emitting diode (LED) and photodiode (PD) pair. The system further comprises a processor to: command applying pneumatic pressure to the bladder of the finger cuff from a low pressure to a high pressure； measure the plethysmogram of the finger cuff as the pressure increases from the low pressure to the high pressure； and determine fitness of the finger cuff on the patient's finger based on the measured plethysmogram. When the finger cuff is placed around the patient's finger, the bladder and the LED-PD pair aid the processor in measuring the plethysmogram.
