The "bilirubin levels" that have been reported in the recent query about fluctuations in Breastmilk Jaundice have apparently been determined by a transcutaneous bilimeter. Only one determination was by blood chemistry measurement. Transcutaneous bilimeter measurements are measurements of the yellowness of the skin and only give an approximation of the serum bilirubin concentation; transcutaneous bilimeters are only suitable as a screening technique. I suspect that repeated serum chemistry bilirubin concentrations would be more consistent. Nevertheless, fluctuations in serum bilirubin levels in Breastmilk Jaundice at 2 to 3 weeks of age are not unusual and this child has a very characteristic pattern of hyperbilirubinemia for a child with Breastmilk Jaundice - although it is at the high end of the range seen. Breastmilk Jaundice is seen in two-thirds of ALL breastfed infants and is a normal extension of physiologic jaundice of the newborn. In any child with an exaggerated level of bilirubin - above 12 or 14 mg/dl, it advisable to do some screening laboratory studies to rule out hemolysis and hypothyroidism. Combined etiologies are always a possibility at these higher levels. Larry Gartner PLEASE NOTE NEW AREA CODE FOR PHONE & FAX Lawrence M. Gartner, M.D. Professor of Pediatrics and Obstetrics/Gynecology The University of Chicago MC6060 5841 S. Maryland Avenue Chicago, IL 60637 Phone: (773) 702-0389 FAX: (773) 702-0764 E-Mail: [log in to unmask]