General information, not an individual diagnosis. Ask a healthcare professional if you are unsure about your situation.
A diagnostic lumbar puncture samples cerebrospinal fluid from the lower back. This fluid circulates around the brain and spinal cord; the procedure is different from a blood test.
The analyses depend on the medical question, such as investigating infection, abnormal cells or inflammation. A puncture may also have another purpose, including measuring fluid pressure; ask which purpose applies to your prescription.
Before the procedure, report your medicines, particularly anticoagulants, and any allergy to local anaesthetics. The doctor checks contraindications and explains preparation; do not change treatment on your own.
The sample is taken in hospital under local anaesthesia. Staff help you round your back and remain still. Tell the doctor if you feel an electric-shock sensation in a leg during the procedure, without making a sudden movement.
A headache after puncture may worsen when standing and ease when lying down. HAS recommends atraumatic needles to reduce this risk; forced bed rest and excessive hydration are not indicated preventive measures.
Before leaving with someone to accompany you, ask whom to contact and how to receive results. Fever, a new neurological problem or a change in the positional nature of the headache after the procedure requires urgent assessment; do not assume it is a usual after-effect.
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