The Leeds Teaching Hospitals NHS Trust


Sterile Samples

Sterile Samples (e.g. CSF, abscess pus, synovial fluid, tissue biopsies)

Specimen types you should send:

  • Sterile body fluid samples (see list below) obtained for microbiological culture
  • Samples should be collected from sterile sites using aseptic techniques.
  • Please indicate if tuberculosis is a possible diagnosis when collecting samples from sterile sites. Samples and request forms should be labeled with Danger of Infection stickers.
  • White cell counts other than on CSF samples should be sent on a separate request to Haematology department.
  • If samples require urgent processing please contact the Microbiology Department

How to Collect the Sample

  • For taking lumbar puncture samples please refer to lumber puncture standard operating procedure
  • Disinfect the skin site thoroughly prior to puncture or incision.
  • If necessary use sterile gloves and sterile drapes around the incision or puncture site.
  • Aspirate the body fluid into a syringe and decant the fluid into the sterile container.
  • Screw the lid back on the container and make sure that it does not leak.

List of samples that fall under above sampling recommendations

  • Cerebrospinal fluid (CSF)
  • Abscess aspirates (from various anatomical locations)
  • Pleural fluid
  • Ascites 
  • Bone biopsy
  • Tissue biopsy (from sterile anatomical sites e.g. brain, liver, spleen, lymph nodes)
  • Bone marrow aspirate
  • Synovial biopsy
  • Synovial fluid samples - joint fluid aspirates (use same containers for synovial fluid crystal detection - please note that samples for crystal detection should reach the lab as soon as possible).


  • Transport the sample to the laboratory as quickly as possible.
  • Note: The recovery of anaerobes is compromised if transport time exceeds 3 hours.
  • Do not refrigerate the sample