[Noninvasive prediction of red blood cell counts by normalized reflection spectroscopy for tongue inspection]

The technology of visible-infrared (Vis-NIR) spectroscopy for tongue inspection was used for the noninvasive prediction of red blood cell counts (RBC). Reflectance spectra on the tongue tips of 240 volunteers were collected, and the tongue picture was recorded at the same time. Samples were separated into two parts: calibration sample and prediction sample. Spectra were then subjected to a partial least squares regression (PLSR) analysis. The correlation between the data and prediction of HCT yielded calibration samples value of 0.991, and RBC levels of prediction samples predicted by this model from Vis-NIR spectra provided a coefficient of determination in prediction of 0.994 with an average relative error of prediction of 0.81%, and a root mean square error of prediction of 0.472. Experiment results showed that the correlation between tongue and RBC exists, and also demonstrated that the tongue can be used as the measure site for noninvasive prediction of RBC. From the results of prediction model and prediction results we can conclude that reflectance spectroscopy of tongue can be used to predict the RBC noninvasively.