Transcutaneous bilirubinometry (TcB)
Studies at the London have shown that transcutaneous measurement of bilirubin levels is safe in our ethnically diverse population as a screening tool. We use the Minolta JM-103 device (detailed laminated instructions are with the instrument on Mary Northcliffe Ward). The test is painless and takes less than a minute to perform. If in doubt visually - screen.
Please note that transcutaneous bilirubinometry is only really valid as a screening tool. Follow the algorithms below and only instigate (and maintain) treatment on the basis of the SBR (blood test), not the TcB reading.
While the baby is under phototherapy lights and for 24 hours afterwards you can not measure bilirubin levels with a transcutaneous device because of skin bleaching. Manage the baby with spun bilirubins only please.
Record all measurements on the phototherapy charts and document your decision making process in the notes.
It is known that the correlation between transcutaneous and serum measurements of bilirubin is less good at higher levels. Because the Minolta JM-103 tends to under read in pale skinned babies and over read in babies with a darker skin, we have chosen a universally safe cut off of 220 micromol/L above which you must do an SBR.
In order to make safe and efficient management decisions for babies with early onset jaundice, you will need the bilirubin reading, the appropriate phototherapy chart, the Bhutani nomogram and mother’s and baby’s notes.
* check gestation, age, maternal blood group, G6PD risk, bruising, signs or history suggestive of polycythaemia, previous sibling with jaundice, method of feeding, signs of sepsis or dehydration