1. A system for detecting glucose in a biological sample, comprising: at least one light source configured to strike a target area of a sample; at least one light filter positioned to receive light transmitted through the target area of the sample from the at least one light source; at least one light detector positioned to receive light from the at least one light source and filtered by the at least one light filter, and to generate an output signal, having a time dependent current, which is indicative of the power of light detected; and a processor configured to receive the output signal from the at least one light detector and based on the received output signal, calculate the attenuance attributable to blood in a sample present in the target area with a ratio factor, and based on the calculated attenuance, determine a blood glucose level associated with a sample present in the target area.