The influence of bilirubin and creatinine on the refractive index of whole blood in terahertz frequency range: a qualitative analysis

The glucose level of blood can be obtained by terahertz time-domain spectroscopy using refractive index measurement method. The detected refractive indices vary from person to person since the impact of bilirubin and creatinine wasn't considered. 14 human blood samples were tested using terahertz time-domain spectroscopy. The experiment results show that under the certain concentration of glucose, the refractive index of blood decreases with the increase of bilirubin and creatinine concentration, and thus the concentration of other blood components may also influence on the refractive index of blood. The feasibility of using terahertz time-domain spectroscopy to determine the level of glucose, bilirubin and creatinine qualitatively and quantitatively is provided.