The diagnostic accuracy of CSF analyses in stroke.

The ability of routine analyses of cerebrospinal fluid (CSF) to differentiate between haemorrhage and infarction was evaluated in 231 stroke patients, whose diagnoses were based on computed tomography or autopsy. In all diagnostic groups the mean protein level was above normal, the highest values being associated with haemorrhage. Taking a protein level greater than 1 g/l to be characteristic of bleeding, sensitivity was 89% and specificity 92%. Spectrophotometric CSF absorbance was measured at wave lengths of 410, 415, 455 and 630 nm. Validity was equal for the first three. Taking absorbance greater than or equal to 0.040 at 415 nm to be diagnostic for haemorrhage, sensitivity was 72% and specificity 94%. The human eye was almost as sensitive as spectrophotometry in this context. Thus, among 100 patients with stroke, 7-9 out of 10 plausible cases of haemorrhage would be identified by means of routine CSF analyses. At the same time, 5-9 patients with ischaemic lesions would be diagnosed incorrectly as bleedings.