EFFECT OF AMBIENT LIGHT ON SERUM BILIRUBIN CONCENTRATION AT AMBIENT TEMPERATURE

Background - Unconjugated bilirubin is photolabile. Light exposure degrades Unconjugated bilirubin both invitro and invivo. Hence the present study was carriedout to assess the effect of light exposure on Serum Bilirubin concentration invitro. Materials Methods - 50 samples (adult, neonatal - normobilirubinemic hyperbilirubinemic) were exposed to normal laboratory light for 2 hours, 4 hours, 6 hours, 8hours. Serum Total and Direct Bilirubin were analysed in these samples using diazo method in fully automated clinical chemistry analyser before light exposure and after every two hours of light exposure. Indirect Bilirubin was calculated. The mean of serum total, direct, indirect bilirubin at various time intervals was compared with the serum concentration before light exposure using Paired t-test. Results - There was a statistically significant difference in mean Total bilirubin concentration at 2 hour (p value0.0006), 4 hour (p value less than 0.0001), 6 hour (p value less than 0.0001), 8 hour(p value less than 0.0001). Statistically difference in mean serum direct bilirubin was observed only after 4 hours (p value 0.044) of light exposure, 6 hours (p value0.005), 8 hours (p value 0.002). Statistically significant difference in mean serum indirect bilirubin was observed only after 6 hours of light exposure (p value0.005), 8hours(p value less than 0.001).Decrease in serum total bilirubin concentration was observed in 34 of samples after 2 hours of exposure. Conclusion - Exposure to ambient lab lighting has no clinically significant change in serum total bilirubin concentration even after exposure to long periods upto 8 hours although there may be a statistically significant change.