The cerebrospinal fluid (CSF) is an invaluable diagnostic tool in clinical neurology, not only in the evaluation of inflammatory, degenerative, and malignant diseases of the nervous system, but also in the diagnosis of all forms of cerebral and subarachnoidal bleedings. The CSF can be easily obtained by lumbar puncture and a set of basic analyses can be conducted using relatively simple laboratory methods. By combining different CSF parameters, a wide range of diagnostic entities can be identified. However, properly interpreting the test results requires a high level of expertise and...