Lipemia is characterized by the turbid to milky appearance of plasma or serum and is secondary to the presence of large lipoproteins,
especially chylomicrons and very low-density lipoproteins (VLDLs). Lipemia can be physiologic or secondary to metabolic disturbances
(e.g. Diabetes mellitus, hyperadrenocorticism). Physiologic lipemia occurs after a meal (post-prandial lipemia) and consists of
chylomicrons derived from food; therefore it can be minimized by implementing a 12 h fasting period prior to blood collection.
The lipemia caused by metabolic disturbances is unfortunately unavoidable, but the testing laboratory can employ techniques such as
repeated high-speed microcentrifugation or clearing agents to minimize it as much as possible.
The effects that either type of lipemia have in some CBC and chemistry determinations are the same. Lipemia will cause a false increase
in hemoglobin and consequently a false increase of the red cell indices calculated using hemoglobin: MCH and MCHC. Changes in red cell
morphology may be seen, in which red cells acquire a fuzzy appearance and angular shapes. Lipemia also predisposes red cells to in vitro
hemolysis. Lipid-droplets may be mistakenly counted as platelets and total protein by refractometry is also inaccurate (false increase).
Lipemia will affect chemistry analytes in different ways due to interference with photometric measurements or water displacement for
electrolytes (false decreases in sodium and chloride determined by indirect potentiometry).