NICE giude, includes guidance on transcutaneous measurement of bilirubin.
How to measure the bilirubin level – use a transcutaneous bilirubinometer in babies with a gestational age of 35 weeks or more and postnatal age of more than 24 hours – if a transcutaneous bilirubinometer is not available, measure the serum bilirubin – if a transcutaneous bilirubinometer measurement indicates a bilirubin level greater than 250 micromol/litre check the result by measuring the serum bilirubin – always use serum bilirubin measurement to determine the bilirubin level in babies with jaundice in the first 24 hours of life – always use serum bilirubin measurement to determine the bilirubin level in babies less than 35 weeks gestational age – always use serum bilirubin measurement for babies at or above the relevant treatment threshold for their postnatal age, and for all subsequent measurements – do not use an icterometer.