A biosensor includes an optical sensor circuit that emits light directed at skin tissue of a patient at a plurality of wavelengths. A first and second spectral response of light reflected from the tissue is obtained around a first wavelength in a UV range and a second wavelength in an IR range. A measurement of a substance in blood flow is then determined from the spectral responses. A risk of a health condition is obtained using the measurement. The health condition may include one or more of hyperglycemia, diabetes or hypoglycemia.
