Since the indictment of bilirubin as an etiologic factor in the development of kern-icterus, widespread attention has been focused upon neonatal jaundice. Frequent bilirubin determinations are now being done on small infants, and a micromethod that obviates the necessity for venipunctures and at the same time can be easily performed would seem desirable. Because the bilirubin producing icterus in the first week of life, associated with erythroblastosis, sepsis, or prematurity, is almost entirely indirect-reacting, a simple method for determination of indirect bilirubin alone should be of practical value. Such a method, based on that originally described by Ernst and Förster1 and modified by Weech and co-workers * in 1941, is now in use at the Children's Hospital. The addition of acetone to serum precipitates direct bilirubin together with protein and leaves indirect bilirubin in the clear yellow supernate, where its concentration can be determined photometrically.
As described by Davidson, Merritt,
MERTZ JE, WEST CD. A Rapid Micromethod for the Determination of Indirect Bilirubin. AMA Am J Dis Child. 1956;91(1):19-22. doi:10.1001/archpedi.1956.02060020021004