Contraindications to performing lumbar puncture (LP):

- INR > 1.4 or other coagulopathy

- Platelets < 50

- Infection at desired puncture site

- Obstructive / non-communicating hydrocephalus

- Intracranial mass

- High intracranial pressure (ICP) / papilledema (relative contraindication depending on etiology; especially a concern with intracranial mass lesion secondary to the increased risk of transtentorial or cerebellar herniation)

- Focal neurological symptoms/signs, decreased level of consciousness

- Partial / complete spinal block

- Acute spinal trauma