Xanthochromia is the yellow discoloration of the cerebrospinal fluid which is colorless in normal conditions. Xanthochromia occurs due to the presence of bilirubin. Bilirubin is present due to the degeneration of red blood cells in the CSF. This is usually seen in subarachnoid haemorrhage (SAH). Examining the centrifuged supernatant CSF for xanthochromia is the best approach to identify RBCs associated with subarachnoid hemorrhage or traumatic tap. Xanthochromia can be confirmed visually, which is the most common method of identification, however, it is accurately identified and analyzed in the lab. Although xanthochromia can occur as a result of a high blood bilirubin level (> 15 mg/dL), individuals with severe hyperbilirubinemia (e.g., from jaundice or known liver illness) are typically detected prior to a lumbar puncture. In a freshly spun specimen, xanthochromia is evidence for the presence of blood in the subarachnoid space. However, it should be noted that a very high CSF protein level, as observed in lumbar punctures below a full spinal block, makes the fluid xanthochromic, even if no RBCs are present. After a subarachnoid haemorrhage, xanthochromia might last for several weeks. As a result, it has a higher diagnostic sensitivity than a non-contrast computed tomography (CT) scan of the head, particularly if the SAH originated more than 3-4 days before presentation. Patients with aneurysmal leaks such as sentinel haemorrhages may appear days after the beginning of their headache, this increases the chances of a false-negative head CT scan. In certain circumstances, such as in pseudomonal meningitis, the CSF may have a different bright green hue.