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

Modified lambert beer for bilirubin concentration and blood oxygen saturation prediction

Noninvasive measurement of health parameters such as blood oxygen saturation and bilirubin concentration predicted via an appropriate light reflectance model based on the measured optical signals is of eminent interest in biomedical research. This is to replace the use of conventional invasive blood sampling approach. This study aims to investigate the feasibility of using Modified Lambert Beer model (MLB) in the prediction of one’s bilirubin concentration and blood oxygen saturation value, SO2. This quantification technique is based on a priori knowledge of extinction coefficients of bilirubin and hemoglobin derivatives in the wavelength range of 440 – 500 nm. The validity of the prediction was evaluated using light reflectance data from TracePro raytracing software for a single-layered skin model with varying bilirubin concentration. The results revealed some promising trends in the estimated bilirubin concentration with mean ± standard deviation (SD) error of 0.255 ± 0.025 g/l. Meanwhile, a remarkable low mean ± SD error of 9.11 ± 2.48 % was found for the predicted SO2 value. It was concluded that these errors are likely due to the insufficiency of the MLB at describing changes in the light attenuation with the underlying light absorption processes. In addition, this study also suggested the use of a linear regression model deduced from this work for an improved prediction of the required health parameter values