Albumin has been used in clinical medicine for more than seven decades. At the time of circulation and deairing of asanguineous primes during CPB, many programs will first remove the prebypass filter before adding albumin to the circulating fluid due to concerns of prebypass filter blockage and over pressurization. However, it should be noted that during the manufacturing process of isolating albumin from human plasma, the extracted albumin is first filtered through a 0.5 micron filter before entering into the ultrafiltration and pasteurization process. Therefore, personal experience and the latter explanation of albumin preparation demonstrate that circulating albumin primes through prebypass filters is not hazardous or contraindicated.