what’s leaking from the nose? differentiating between CSF from other secretions

1. double ring sign – place 1ml of fluid on absorbent filter paper; if csf = central circle of blood and outer clear ring of csf
2. dipstick – absence of glucose excludes csf (presence of glucose is not diagnostic since nasal secretion and tear contain glucose as well). presence of protein

note:

csf -

• protein 20-40mg/dL; glucose 50-100mg/dL