CSF findings depend on how close the hematoma is to the subarachnoid space. If penetration to the brain surface occurs, the CSF resembles that of subarachnoid hemorrhage; if situated relatively far from the brain surface, the CSF will be relatively normal. About 20% (literature range, 15%-25%) of cases are said to have clear CSF; the remainder are xanthochromic or contain blood. Cell count and protein values reflect the presence of spinal fluid blood and the closeness of the hematoma to the meninges. With bloody fluid, protein and cell count initially reflect the RBC count; after 12 or more hours, protein level and cell count may rise disproportionately to the number of RBCs, sometimes to moderately high levels (similar to effects of subarachnoid hemorrhage). CT and MRI are the best methods for diagnosis, with CT better than MRI in the first week.