Methods for in-vitro analysis of biological cells and/or microorganisms to determine characteristics such as: degree of differentiation, cell type, donor individuals, culture conditions, purity, lack of natural characteristic, or additional characteristics in comparison to natural characteristics. The methods include the steps of: (a) projecting infrared radiation on a sample; (b) recording spectral characteristics of the sample; (c) deriving a Fourier transform infrared spectrum (FT-IR) from the collected spectral characteristics; (d) generating a derivative transformation of the FT-IR spectrum; (e) comparing said derivative transformation with a derivative of a reference FT-IR spectrum; (f) identifying deviations of said derivative from said reference derivative; and (g) providing an analysis of said characteristics based on the presence of said deviations. In addition, the invention relates to an apparatus for carrying out the disclosed methods.