Page updated 30 April 2007
Guidelines for Appropriate Specimen Collection
As a general rule, the more material sent for examination, the greater the chance of isolating significant bacteria. A few ml of pus is much better than a swab. If in doubt send the pus in a sterile universal plus a swab in transport medium. Use a syringe and needle to collect specimen and transfer into a sterile container eg Universal or plain sterile blood collection tube. Be very careful to avoid "Sharps" injury.
Plain vacutainer tubes are good, as anaerobic conditions are maintained.
NB: SPECIMENS MUST BE TRANSPORTED TO THE LABORATORY WITHOUT DELAY!
If there is likely to be a delay in transporting to the laboratory, a specimen in transport medium (eg Transwab) is preferred.
Transport media advantages:
- Maintain viability of bacteria.
- Anaerobes preserved, even those that are killed on short exposure to air.
- Effective for 18 hours at room temperature.
- Delicate bacteria such as Neisseria spp. and Haemophilus spp. preserved.
Transport media disadvantages:
- Material is lost from swab into medium and fewer than a third of organisms can be recovered from a swab onto agar.
- Relative proportion of bacteria is altered when specimen transport to the laboratory is delayed.
- Coliforms and normal flora may increase.
- Numbers of pathogens may decrease.
NOTES:
- Specimens are readily contaminated by poor technique (eg allowing urine to flow over the vulva before collection into the container. or collecting specimens from stagnant bags rather than drainage tubes).
- Samples should be collected before the commencement of antibiotic treatment or just before a dose is given.
- If antiseptic is used for cleaning or packing a wound, the specimen should be collected before the antiseptic is applied.
Labelling:
Minimum information required on specimen label :
- Name, Patient Identification number.
- Location of the patient
- Site / type of specimen,
- Date and time of collection,
- Test required (if a paperless system)
Information required on request form or computer request:
As per specimen label,
- Age, Sex.
- Provisional diagnosis.
- Pyrexia, wound infection.
- Surgical, traumatic, dirty.
- Chemotherapy.
- Consultant and requesting doctor with contact number.
and - Legible, please.
Other information to be considered that may be relevant and enable the laboratory to consider further tests:
- Recent travel abroad, (where?).
- Immunosuppressed: HIV, Radiotherapy, Cytotoxics.
- Occupation: Farming, Animals, Industry.
- Sports: Caving, Watersports, Hiking, Camping.
All these factors influence the way in which we process specimens.
Failing to produce a completed request form or a delay putting request on to the computer delays laboratory processing, even if the specimen has been delivered to the laboratory. Unlabelled specimens will not be processed.
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