Xanthochromia of cerebrospinal fluid (CSF) suggests the following EXCEPT
ExplanationNormal CSF contains no Red Blood Cells (RBCs); thus, their presence indicates a traumatic tap or a subarachnoid haemorrhage. Progressive clearing of the blood between the first and last samples indicates a traumatic tap. Bloody CSF should be centrifuged immediately. A clear supernatant is consistent with a bloody tap, whereas xanthochromia (yellow colour that results from the degradation of haemoglobin) suggests a subarachnoid haemorrhage. Xanthochromia may be absent in bleeds <12 hr old, particularly when laboratories rely on visual inspection rather than spectroscopy. Xanthochromia can also occur in the setting of hyperbilirubinemia, carotenemia, and markedly elevated CSF protein.
