Reflectance spectroscopy system for real time and non-invasive detection of transcutaneous bilirubin level

Blood bilirubin level would be elevated when one's liver is unable to remove bilirubin sufficiently from the blood. The conventional methods used for monitoring and measuring the bilirubin level are time consuming, tedious and invasive in nature. This study aims to investigate the feasibility of using Modified Lambeti Beer (MLB) A model in the prediction of one's bilirubin concentration using a priori knowledge of the extinction coefficient of bilirubin and haemoglobin components in the wavelength range of 400 500 nm. This study verified validity of the predicted value using light attenuation data from TracePro for a single-layered skin model with varying bilirubin concentration. The results revealed some promising trends in estimated bilirubin concentration and considerably good accuracy with percent mean relative error in the predicted bilirubin concentration, Cbil(p) calculated as 59.9 %. This study performed contact and non-contact experiments for the demonstration works. A total number of 60 individuals of different health status, skin tone and gender have been recruited for the contact experiment. Meanwhile, six healthy subjects was recruited for the noncontact experiment, and measurement was performed at various selected skin sites. From the contact experiment, this work found a lower skin bilirubin level in renal disease subjects compared to healthy subjects. In addition, a lower bilirubin was observed for individuals with dark skin compared to fair skin, and a higher bilirubin level in male compared to their female counterparts. Based on the experiments performed on healthy subjects using non-contact experiment arrangement, this work found that palm site has the lowest in the predicted mean transcutaneous bilirubin concentration with highest consistency given by 0.44±0.4 g/1 as compared to other skin sites. This study concluded that the developed system and strategy may be used as an alternative means to assess one's skin bilirubin level.