The effect of Intralipid on the estimation of serum bilirubin in the newborn infant.

After noting rises in measured serum billirubin in premature infants undergoing parenteral nutrition, a series of experiments was designed to ascertain the effect of the presence of Intralipid on the actual laboratory analysis. It has been shown that the most commonly used spectrophotometric analysis of bilirubin and the estimation of direct bilirubin by micromethods are affected by the presence of Intralipid in the specimens. Centrifugation of the blood samples at 15,000 rpm for 10 minutes and analysis of the aqueous layer overcomes, in both methods, the interference and error introduced by the presence of Intralipid chylomicrons in patient sera. Alternatively spurious bilirubin measurements due to hyperlipidemia may be avoided by using a bilirubinometer equipped with a filter which eliminates the effect of Intralipid interference.