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Information about a lumbar puncture

Patient information A-Z


This patient information page has been produced using the information produced by Luton and Dunstable University Hospital.

What is a lumbar puncture?

Your baby was started on antibiotics due to risk factors for infection and/or clinical concerns, suggestive of the presence of infection.

When there is evidence of infection on your baby’s blood test results, we may want to take a sample of the fluid that surrounds the spinal cord called cerebrospinal fluid. This fluid flows down from the brain; so analysing it should show whether the infection is present in this vital part of the nervous system.

You should seek medical help from your midwife, GP, NHS direct or the emergency department if you are concerned that your baby has any of the following:

  • is showing abnormal behaviour (for example, inconsolable crying, or listlessness)
  • is unusually floppy
  • has developed difficulties with feeding or with keeping feeds down
  • has a temperature lower than 36°C or higher than 38°C
  • has rapid breathing
  • has a change in skin colour (for example, mottled/grey/blue)

The procedure

If we need to take this sample we will do it in the treatment room on Charles Wolfson Ward. The procedure is done under sterile conditions to minimise any risk to your baby of further infection. Your baby may be offered some sucrose (sugar water) solution as simple pain relief during the procedure.

A small needle is used and is placed between two bones low in your baby’s back. While many important nerves run though the spine, they will not be damaged because these nerves are all higher than the level where this needle is placed.


The fluid sample will be sent to the lab for culture and the results should be available within 48 hours. This will further help decide the duration of the antibiotic treatment and whether further investigations are needed.

When to see medical help once at home with your baby

If your baby received antibiotics, or, was observed for 12 hours due to risk factors for infection, it is important to be aware of signs that suggest your baby is becoming unwell after discharge home.

Where to get further information

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Smoking is not allowed anywhere on the hospital campus. For advice and support in quitting, contact your GP or the free NHS stop smoking helpline on 0800 169 0 169.

Other formats

Help accessing this information in other formats is available. To find out more about the services we provide, please visit our patient information help page (see link below) or telephone 01223 256998.

Contact us

Cambridge University Hospitals
NHS Foundation Trust
Hills Road, Cambridge

Telephone +44 (0)1223 245151