March 1981 454 TheJournalofPEDIATRICS Transcutaneous bilirubinometry. L Correlations in term infants The transcutaneous bilirubinometer was evaluated in 43 white infants, eight black infants, and in nine white infants treated with phototherapy. The reproducibility of the instruments was determined after trials consisting of both five and 100 repetitions. Among the infants not being treated with phototherapy, TcB index and serum bilirubin concentration correlated at 0.90 level in both white and black infants. Phototherapy reduced the accuracy of the TcB and, at the present time, the use of this index in infants under light therapy cannot be recommended. Otherwise the TcB is a valuable tool in screening healthy term infants for hyperbilirubinemia. Thomas Hegyi, M.D.,* I. Mark Hiatt, M,D., and Leonard Indyk, Ph.D., Long Branch, N.J. THE ABILITY to monitor clinically important physiolog- ic measurements represents a major advance in neonatal medicine. Standard clinical management of infants with hyperbilirubinemia includes serial estimation of serum bilirubin concentrations by laboratory techniques using blood obtained by repetitive heel pricks. This technique of blood sampling serves as a source of discomfort and of serious infection.' The transcutaneous bilirubinometer is a reflectometer which permits the noninvasive monitoring of neonatal hyperbilirubinemia. Yamanouchi and co-workers ~ have evaluated the precision and accuracy of the TcB in a group of term Japanese infants. The present study evalu- ates the accuracy and precision of the TcB using a sample of black and white term infants. PATIENTS AND METHODS The study population consisted of 60 term healthy infants admitted to the newborn nursery of Monmonth Medical Center. Candidates for the study included all infants whose clinical course required the monitoring of serum bilirubin concentration. At the time of blood sampling TcB measurements were obtained at nine body From the Division of Neonatology, Department of Pediatrics, CMDNJ-Rutgers Medical School, and the Division of Neonatology, Monmouth Medical Center. *Reprint address: Department of Pediatrics, CMDNJ-Rutgers Medical School, Piscatawafl, NJ 08854, sites: forehead, sternum, right upper abdomen, knee, sole, elbow, palm, upper back, and lower back. Total serum bilirubin concentration was measured by a spectropho- tometric technique corrected for hemolysis and for increased direct bilirubin. 3 Abbreviation used TcB: transcutaneous bilirubinometer All infants were cared for in bassinets except those receiving phototherapy, who were nursed naked in incu- bators (Isolette, Air Shields, Hatboro, Pa.). The photo- therapy unit was equipped with eight special blue fluores- cent lamps (Westinghouse, F-20T12/BB) encased in a standard nursery phototherapy module (Air Shields, Hat- boro, Pa.) and positioned above the incubator. The TcB (Minolta Camera Co., Japan) and its princi- ples of operation have been previously described in detail? In brief, it is a spectral reflectometer that measures the color intensity of the skin and subcutaneous tissue, and then processes this measurement to provide a numer- ical TcB index. The clinical performance of the TcB was evaluated with respect to several factors that were assumed to influence the numerical index: multiple measurements, body site, race, phototherapy, postnatal age, and level of serum bilirubin concentration. In order to examine the reproducibility of the index, defined as precision, the TcB was tested on eight patients Vol. 98, No. 3, pp. 454-457 0022-3476/81/030454+04500.40/0 9 1981 The C. V. Mosby Co.