Neurology• Updated 21 October 2026
Lumbar Puncture
A procedure that takes a small sample of the fluid around the brain and spinal cord from the lower back.
Results: A few hours to days Specimen: Cerebrospinal fluid
Quick Summary
Primary Purpose
To diagnose meningitis, bleeding around the brain and some neurological conditions.
What It Measures
Cells, protein, glucose and germs in the spinal fluid.
Preparation
Tell staff about blood thinners.
Overview
A needle is placed between bones in the lower back below where the spinal cord ends.
Headache afterwards is the most common side effect.
What It Measures
Cells and protein
Signs of infection or inflammation.
Culture
Bacteria.
How It's Performed
- 01
Position
Lie curled on your side or sit leaning forward.
- 02
Procedure
Local anaesthetic, then a thin needle; takes 15–30 minutes.
- 03
Recovery
Rest and drink fluids.
Sources and further reading
Last updated 21 October 2026. For more detail, see these trusted health organisations.
- Cerebrospinal Fluid (CSF) Analysis(opens in a new tab) · MedlinePlus, US National Library of Medicine
- Lumbar puncture(opens in a new tab) · NHS