The problems encountered in biology are usually complex and often not totally understood. Mathematical modeling provides a means to better understand the processes and unravel some of these complexities. This book presents a model for detecting diabetes Mellitus in the blood. Epinephrine has been successfully incorporated as a third variable in the existing model of blood glucose regulatory system (BGRS). The importance of this third variable lies in its ability to help in conducting a reliable test for detecting diabetes in the blood. This leads to a system of linear homogenous equations whose solution provides the blood glucose concentrations for diabetics and non diabetics. This model has been found to be asymptotically stable since the the eigenvalues of the coefficient matrix are complex numbers with negative real parts. The resonance period for this new model is also far less than that for the existing model. This shows that the glucose concentration returns to normal level within a shorter time. This model would help the medical practitioners to predict diabetics from non diabetics.