Systems and methods for characterizing biological specimens, which may involve identifying a cell type or state corresponding to a disease or health condition of a subject. A biological specimen is subjected to electromagnetic radiation for spectroscopic analysis such as Surface Enhanced Raman Spectroscopy (SERS) to determine the relative abundance of proteins or amino acids in the cells, which is used in a comparison to previously stored relative abundance data of a database to automatically identifies at least one of cell type and/or cell state of the cells (or the disease/health state of the subject with the disease state including the possibility of virus infection, or drug susceptibility of a subject to bacteria or fungus). The method may also be employed with biological entities or cellular structures such as exosomes and even protein or nucleic acid fragments to determine disease states or health states of the subject.