A system and method embodying the invention can be used to detect a characteristic or condition of a patient. A method embodying the invention may include the steps of illuminating a portion of a skin of the patient with light, detecting a frequency spectrum of light scattered from the skin, determining, from first and second portions of the spectrum, a first parameter indicative of a blood content of the skin and a second parameter indicative of a melanin content of the skin, determining, from a third portion of the spectrum, a third parameter indicative of an uncorrected bilirubin concentration, and calculating a corrected bilirubin concentration based on the first, second and third parameters.