Laboratory diagnosis of subarachnoid haemorrhage

Abstract

The diagnosis of CT-negative subarachnoid haemorrhage (SAH) is an important clinical challenge in clinical neurology. Cerebrospinal fl uid (CSF) analysis via lumbar puncture is the method of fi rst choice. The diagnosis of SAH in CSF is based on a bloody or xanthochromic discoloration of the CSF as well as on fi ndings in nonautomated CSF cytology including the detection of erythrophages and siderophages. The automated determination of CSF ferritin concentrations or spectrophotometric detection of xanthochromia may contribute to the diagnosis but are only useful with regard to the overall clinical picture. Generally, the knowledge of the time fl ow of the CSF changes associated with SAH (8–12 h after onset of headache) is essential for a correct interpretation of CSF fi ndings.