A biosensor system, comprising: a PPG circuit configured to: emit light having at least a first wavelength and a second wavelength directed at skin tissue of a patient, wherein the first wavelength has a high absorption coefficient for at least one liver enzyme and the second wavelength has a lower absorption coefficient for the at least one liver enzyme; generate a first spectral response using light around the first wavelength reflected from or transmitted through the skin tissue of the patient; generate a second spectral response using light around the second wavelength reflected from or transmitted through the skin tissue of the patient; at least one processing circuit configured to: obtain a value R λ1, λ2 using the first spectral response and the second spectral response, wherein the value R λ1, λ2 is an indicator of the at least one liver enzyme; and obtain a blood alcohol level using the value R λ1, λ2, wherein the at least one processing circuit is further 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 L λ2 using a ratio of the systolic point and diastolic point in the second spectral response; and obtain the value R λ1, λ2 from a ratio of the value L λ1 and the value L λ2. emit light having at least a first wavelength and a second wavelength directed at skin tissue of a patient, wherein the first wavelength has a high absorption coefficient for at least one liver enzyme and the second wavelength has a lower absorption coefficient for the at least one liver enzyme; generate a first spectral response using light around the first wavelength reflected from or transmitted through the skin tissue of the patient; generate a second spectral response using light around the second wavelength reflected from or transmitted through the skin tissue of the patient; at least one processing circuit configured to: obtain a value R λ1, λ2 using the first spectral response and the second spectral response, wherein the value R λ1, λ2 is an indicator of the at least one liver enzyme; and obtain a blood alcohol level using the value R λ1, λ2, wherein the at least one processing circuit is further 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 L λ2 using a ratio of the systolic point and diastolic point in the second spectral response; and obtain the value R λ1, λ2 from a ratio of the value L λ1 and the value L λ2. 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 L λ2 using a ratio of the systolic point and diastolic point in the second spectral response; and obtain the value R λ1, λ2 from a ratio of the value L λ1 and the value L λ2.