Pathology Handbook

Blood Culture

Synonyms

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Clinical Indications

If systemic fungal or Mycobacterial infection is suspected

Test Includes

Culture for aerobic and anaerobic bacteria

Request Form 

Request on ICE 

Availability

On request.

Specific Criteria

Please give detailed clinical information, including date of onset/contact with the suspected infection, including any current, or intended, antibiotic therapy 

Patient Preparation

It is vital that an aseptic technique is used when collecting blood cultures.

Hands must be thoroughly washed.

The venepuncture site cleansed using an isopropyl alcohol swab, swabbing from the centre of the intended puncture site in a circular movement away from the centre point
Please note: The rubber seals on blood culture bottles are NOT sterile and MUST be cleaned before inoculating the bottles.  Remove the protective flip cap and clean the rubber seal on each bottle with an isopropyl alcohol swab.  DO NOT use a swab previously used on a patient's skin.

When using a multi-point needle and blood culture adaptor, first collect any routine samples (if no other tests are requested a specimen should be withdrawn and discarded,) followed by the blood culture bottles.

If a needle and syringe is used, put a new needle on the syringe after collecting the blood and before inoculating the bottles.  See "Volume" below for the required amounts of blood 

Turnaround Time

Cultures are incubated for up to 5 days (14 days if sub-acute bacterial endocarditis [SBE] is suspected) before reporting as negative. Positive cultures are reported as soon as growth is detected

Specimen

Whole blood

Volume

ADULT ROUTINE: A routine blood culture set consists of two bottles: aerobic - blue top and anaerobic - purple top

Each bottle should be inoculated with 5-10 ml of blood

It is imperative that no more than 10 ml of blood is introduced into each bottle  PAEDIATRIC ROUTINE: A single bottle (yellow top) set is used, requiring the inoculation of up to 4 ml of blood

ENDOCARDITIS: If endocarditis [SBE] is suspected, it is STRONGLY recommended that a minimum of 3 sets of blood cultures be taken before antibiotic therapy is commenced

Each set must be taken at different times from different sites and sent to the laboratory with a separate request form for each set stating the date, time and site of collection

Container

Blood culture bottles 

Collection

Samples should be transported to laboratory immediately. Outside normal working hours the culture bottles must be sent to the Pathology Laboratory and placed in the pathology incubator located in Reception. DO NOT TRANSPORT VIA AIR TUBE.

Causes for Rejection

Unlabelled / inadequately labelled sample

Reference Range

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Lab Handling

Incubate on arrival