[Clinical-biological approaches to the spectrophotometric detection of oxyhemoglobin and bilirubin in CSF in the management of aneurysmal subarachnoid hemorrhage].

The diagnosis of subarachnoid hemorrhage (SAH) is extremely important for appropriate management. Cerebral computed tomography (CT), used as the first-line investigation to detect bleeding, has excellent sensitivity if performed promptly, but its sensitivity falls sharply with the time elapsed since the onset of SAH. Oxyhemoglobin and bilirubin, the breakdown products of heme, are detectable in cerebrospinal fluid (CSF) by spectrophotometric absorption, which defines the search for xanthochromia pigment in CSF. Both parameters can be sought when imaging is negative or doubtful with a strong suspicion of SAH based on clinical signs. In this context, our working group at the Société Française de Biologie Clinique (SFBC) is proposing recommendations to provide medical biologists with support for the implementation and validation of "oxyhemoglobin and bilirubin in CSF" test and enabling them to play their part in the diagnostic process. From the pre-analytical stages through to the delivery of results, we will summarize the pitfalls to be avoided, the main decision values and different physiological and pathological profiles.