1. A system for detecting glucose in a biological sample, comprising: at least one light source configured to generate one or more light beams having a wavelength in a range between 800 nm and 1600 nm and to strike a target area of a sample; at least one photocurrent signal generating light detector positioned to receive light from the at least one light source and to generate an output photocurrent signal, having a time dependent current, which is indicative of the power of light detected; and a light absorbance change determining algorithm implemented processor programmed to calculate a change in a light absorption caused by blood in the biological sample and configured to receive the output photocurrent signal from the at least one photocurrent signal generating light detector and based on the received output photocurrent 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; wherein the light absorbance change determining algorithm implemented processor is configured to calculate the ratio factor using a standard deviation of a logarithm of the time dependent output photocurrent current generated by the light power from the same target area of the biological sample, wherein the light absorbance change determining algorithm implemented processor is configured to calculate the ratio factor Y ij (C,T) at a plurality of wavelengths, the i th wavelength being represented by λ i , the j th wavelength being represented by λ j , C is a blood glucose concentration, T is temperature of the biological sample, I D (λ i , t) is the time dependent output current, σ[log I D (λ i ,t)] is standard deviation of the logarithm of the time dependent output current, and t is time, according to the equation: Y ij ⁡ ( C , T ) = σ ⁡ [ log ⁢ ⁢ I D ⁡ ( λ i , t ) ] σ ⁡ [ log ⁢ ⁢ I D ⁡ ( λ j , t ) ] .