The blood level in an oxygenator is monitored in two stages using a reference and minimum value. Our BCS capacitive sensor indicates when the blood level drops below the minimum value. It is attached using adhesive tape that has been applied to the blood reservoir. This allows it to be reused multiple times. It's position can be selected freely. Deposits are disregarded thanks to smart level technology. This makes it so that the actual blood level is monitored and the doctor can keep it at the right level.