Pathology Microbiology RWF-MIC-LI746 Revision 1.
0
XX1.1
Microbiology User Information: Blood Cultures
Specimen Type: Blood
Indications for Blood Culture:
Trust Sepsis Resources are available on the trust intranet site: ‘sepsis and deteriorating patients’
Hospital antimicrobial guidelines for sepsis: Sepsis (formularywkccgmtw.co.uk)
Request form requirements:
Providing adequate clinical details to microbiology request forms is vital for the safety of
laboratory staff and ensuring patient tests are correctly interpreted.
Please state all relevant clinical history, including travel history (where and when), current or
recent antibiotic therapy and site of sampling.
Blood Culture Bottles:
Adult Blood Culture Set: 2 bottles Paediatric Blood Culture: 1 yellow bottle
One Green, One Pink
(2 sets- 4 bottles should be sent)
Document title: User Information: Blood Cultures Page 1 of 3
Approved by: Lead Consultant Microbiologist Validated by: (signature)
Date of issue: August 2023 Master copy registered on Pathology Qpulse database
Pathology Microbiology RWF-MIC-LI746 Revision 1.0
XX1.1
Specimen Collection Method:
Blood Culture Collection Instructions and Self-assessment form
Collect specimens before antimicrobial therapy where possible.
Collect specimens as soon as possible after the onset of clinical symptoms. Although blood can be
sampled at any time, drawing blood at, or as soon as possible after a fever spike is optimal , except
in endocarditis where timing is less important
Blood cultures can be taken at any time out-of-hours, there is no requirement to notify Microbiology
staff when blood cultures are taken.
Specimens do not require specific incubation temperature and can remain at ‘room temperature’
overnight if needed. DO NOT REFRIGERATE.
Adults:
8-10 ml (fill to the line)
Preferably, a total volume of at least 40mL (two
sets) should be collected .
In case of suspected endocarditis and fever of
unknown origin, an extra set is required to
improve the sensitivity of the test (a total volume
of up to 60 mL)
The chance of obtaining a positive blood culture
is closely related to the volume of blood sampled
and their optimal (timely) processing. Blood
stream infection detection rate increases by 3%
for each extra millilitre of blood cultured.
Document title: User Information: Blood Cultures Page 2 of 3
Approved by: Lead Consultant Microbiologist Validated by: (signature)
Date of issue: August 2023 Master copy registered on Pathology Qpulse database
Pathology Microbiology RWF-MIC-LI746 Revision 1.0
XX1.1
Children and neonates:
No more than 1% of the total blood volume
Time to laboratory:
Blood culture bottles should be sent to the laboratory as soon as possible as they must be
loaded onto the analyser for testing within 4 hours of collection.
TWH: These can be sent to Pathology via the POD system
Maidstone: Please call a porter for delivery to the microbiology department
For information on transport, including days and times, please see Pathology Transport Services
Blood cultures can be taken at any time out-of-hours, there is no requirement to notify Microbiology
staff when blood cultures are taken.
Specimens do not require specific incubation temperature and can remain at ‘room temperature’
overnight if needed. DO NOT REFRIGERATE.
Laboratory Testing:
All Microbiology laboratory investigations are based on UK Standards for Microbiology
Investigations which can be found HERE. If further advice is required, please contact the
laboratory
Laboratory Turn Around Time (from Date/Time of Receipt in Laboratory):
Blood cultures are incubated for at least 5 days.
Negatives: Interim report at 48 hours (and 36 hours for neonatal), Final report at 5 days
Positive microscopy and culture results will be telephoned as soon as possible after they become
available.
Time limit for requesting additional investigations:
n/a
Adverse factors affecting the interpretation of microscopy and culture results:
• Transport to the laboratory < 4 hours, and 2 sets filled 8-10ml each (adults) is the best
way to minimise uncertainty of results
• Delays in processing may result in degradation of microorganisms which generates results
that do not reflect the true clinical situation
• Contamination of blood cultures complicates interpretation and may lead to unnecessary
antimicrobial therapy and increased costs
Document title: User Information: Blood Cultures Page 3 of 3
Approved by: Lead Consultant Microbiologist Validated by: (signature)
Date of issue: August 2023 Master copy registered on Pathology Qpulse database
