A biosensor, comprising: a PPG circuit configured to: emit light having at least a first wavelength and a second wavelength directed at outer epidermal layer of skin tissue of a patient; generate a first spectral response for light detected around the first wavelength from the outer epidermal layer of the skin tissue of the patient; generate a second spectral response for light detected around the second frequency from the outer epidermal layer of the skin tissue of the patient; a processing circuit configured to: isolate a systolic point and a diastolic point in the first spectral response and obtain a value L λ1 using a ratio of the systolic point and the diastolic point in the first spectral response; isolate a systolic point and a diastolic point in the second spectral response and obtain a value E λ2 using a ratio of the systolic point and diastolic point in the second spectral response; obtain a value R λ1, λ 2 from a ratio of the value L λ1 and the value L λ2; obtain a blood glucose concentration level from a calibration table using the value R λ1, λ2; and transmit the blood glucose concentration level for display. a PPG circuit configured to: emit light having at least a first wavelength and a second wavelength directed at outer epidermal layer of skin tissue of a patient; generate a first spectral response for light detected around the first wavelength from the outer epidermal layer of the skin tissue of the patient; generate a second spectral response for light detected around the second frequency from the outer epidermal layer of the skin tissue of the patient; emit light having at least a first wavelength and a second wavelength directed at outer epidermal layer of skin tissue of a patient; generate a first spectral response for light detected around the first wavelength from the outer epidermal layer of the skin tissue of the patient; generate a second spectral response for light detected around the second frequency from the outer epidermal layer of the skin tissue of the patient; a processing circuit configured to: isolate a systolic point and a diastolic point in the first spectral response and obtain a value L λ1 using a ratio of the systolic point and the diastolic point in the first spectral response; isolate a systolic point and a diastolic point in the second spectral response and obtain a value E λ2 using a ratio of the systolic point and diastolic point in the second spectral response; obtain a value R λ1, λ 2 from a ratio of the value L λ1 and the value L λ2; obtain a blood glucose concentration level from a calibration table using the value R λ1, λ2; and transmit the blood glucose concentration level for display. isolate a systolic point and a diastolic point in the first spectral response and obtain a value L λ1 using a ratio of the systolic point and the diastolic point in the first spectral response; isolate a systolic point and a diastolic point in the second spectral response and obtain a value E λ2 using a ratio of the systolic point and diastolic point in the second spectral response; obtain a value R λ1, λ 2 from a ratio of the value L λ1 and the value L λ2; obtain a blood glucose concentration level from a calibration table using the value R λ1, λ2; and transmit the blood glucose concentration level for display.