The present invention provides methods for assessing a condition in an individual by analyzing a cerebrospinal fluid sample from the individual, for example, by spectroscopy. Further, the invention provides methods for determining an amount of blood in the cerebrospinal fluid sample; methods for determining concentrations of analytes in the cerebrospinal fluid sample; methods for determining a length of time the blood has been in the cerebrospinal fluid sample; and methods for rapidly obtaining a differential diagnosis between conditions indicated by blood in the cerebral spinal fluid. Moreover, the present invention provides instruments capable of rapidly assessing a condition in and individual by point-of-care analysis of a cerebral fluid sample from an individual.