If a blood donor consumes food with high fat content such as oily foods which are fried or deep fried before blood donation it can lead to a transient rise in the triglycerides or cholesterol levels resulting in lipemic blood. The plasma and platelets obtained from lipemic blood are normally discarded.
After centrifugation of donated blood the plasma usually appears as a clear, pale yellow color. Lipemic blood occurs because chylomicrons are big particles and scatter light. When the concentration of chylomicrons is high, light is scattered producing a milky color. This condition is called lipemia. Chylomicrons consist of mainly triglycerides and a small amount of cholesterol.
Dietary fat is broken down and absorbed by the small intestine. Chylomicrons are then formed in the cells of the small intestine and secreted into the bloodstream. When the concentration of chylomicrons in the blood reaches a certain level the plasma which is normally light yellow in color will turn milky. This is called lipemia. At a high concentration of chylomicrons the plasma appears like milk with a tinge of pink. It is also turbid and opaque.
Lipemia is a normal physiological condition. Dietary fat is absorbed by the cells lining the intestinal wall and secreted into the bloodstream as chylomicrons which cause lipemia. Generally, the level of chylomicrons in blood is proportional to the dietary fat intake. Its level reaches the peak 2 to 4 hours after a meal and returns to the fasting level after 8 to 10 hours. So, avoid taking food with high fat content the night before your blood donation.
Lipemia does not affect blood safety. However, the appearance of lipemic plasma does not conform to the appearance of normal plasma. The Macao Blood Transfusion Service will discard plasma and platelets components which are markedly lipemic but the red blood cells can still be used for transfusion.
The increase in chylomicrons in the blood is a transient phenomenon. This condition can be improved by maintaining a healthy diet. Only a few individuals with persistent lipemia will need medical consultation. If a blood donor is found to have lipemia repeatedly but the intake of high dietary fat and consumption of alcohol are excluded as the causes of lipemia, it is possible that there is a disorder in the fat metabolism function of the liver or in the function of the enzyme lipoprotein lipase. The doctor at MBTS will follow up with the blood donor and refer the blood donor to a health center or a hospital for further investigation.