Change of bilirubin photoisomers in the urine and serum before and after phototherapy compared with light source.
BACKGROUND
The clinical effect of phototherapy for neonatal hyperbilirubinemia is based on the production and elimination of cyclobilirubin. Generally, the clinical effect of light sources is estimated by the reduction in the total serum bilirubin level. One procedure with less invasiveness than blood collecting is urine collection. Whether the effectiveness of light sources used for phototherapy could be assessed using measurements of bilirubin photoisomers in urine was studied.


METHODS
This study was a retrospective analysis of 38 term infants with hyperbilirubinemia who underwent phototherapy. Bilirubin fractions in serum and urine before and 24 h after the phototherapy were measured by high-performance liquid chromatography. The light sources used for the phototherapy were blue-white light (n = 11), Biliblanket plus high output (n = 13) or green light (n = 14). The relationships between serum and urine bilirubin photoisomers after phototherapy and whether the levels of urine bilirubin photoisomer are affected by the light sources with different wavelength characteristic were analyzed.


RESULTS
There was no correlation between serum (ZE)-bilirubin and urine configurational isomers, but a weak positive correlation between serum (EZ)-cyclobilirubin and urine structural isomers after phototherapy. Although serum (ZE)-bilirubin levels depended on the wavelength characteristic of each light source during phototherapy, the urine configurational isomer levels did not depend on it. The increase in serum (EZ)-cyclobilirubin levels and the urine structural isomer levels were mostly in agreement.


CONCLUSIONS
The urine bilirubin structural isomers may be used to estimate the serum (EZ)-cyclobilirubin levels and to evaluate the clinical effects of light sources.
Okada
Hitoshi
H
Department of Pediatrics, Kagawa University, Kagawa, Japan. hiokada@kms.ac.jp
Masuya
Kumiko
K
Kurono
Yuki
Y
Nagano
Keiko
K
Okubo
Kensuke
K
Yasuda
Saneyuki
S
Kawasaki
Ayako
A
Kawada
Kou
K
Kusaka
Takashi
T
Namba
Masanori
M
Nishida
Tomoko
T
Imai
Tadashi
T
Isobe
Kenichi
K
Itoh
Susumu
S
D001663:Bilirubin / Q000097:blood* / Q000652:urine*; D002851:Chromatography, High Pressure Liquid; D005260:Female; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D007536:Isomerism; D007567:Jaundice, Neonatal / Q000175:diagnosis* / Q000628:therapy*; D008297:Male; D010777:Photochemistry; D010789:Phototherapy / Q000379:methods*; D011336:Probability; D011379:Prognosis; D012189:Retrospective Studies; D018570:Risk Assessment; D012720:Severity of Illness Index; D047929:Term Birth; D016896:Treatment Outcome
D001663:Bilirubin