Laboratory Test Information Guide

Details for Blood Culture – Aerobic/Anaerobic (Adult)

Test Name: Blood Culture – Aerobic/Anaerobic (Adult)
Alternate Name(s):  
Laboratory: Microbiology
Specimen Type: Blood
Collection Information: This sample type cannot be processed as a STAT request. Results are reported as they become available.

Blood cultures should be collected on each patient based on the clinical suspicion of a septic episode. Two sets of blood cultures from separate venipuncture sites, drawn within a 24 hour period and prior to antibiotic therapy, are recommended; an adult blood culture set consists of an aerobic bottle with a silver top and an anaerobic bottle with a red top. If endocarditis is suspected, collect a third set.

Sequential blood cultures are collected at least 30 minutes apart when it is necessary to document continuous bacteremia in the case of suspected endocarditis or other endovascular infections; otherwise blood cultures may be obtained simultaneously provided alternative sites are accessed.

Catheter associated bacteremia (CAB)
If catheter associated bacteremia (CAB) is being investigated, collect a set of blood cultures through the central line and a concurrent set of peripheral blood cultures.

Indicate "CAB INVESTIGATION" in “Specimen Description” on the orders screen and specify site of each collection. An absolutely accurate collect date and time must be entered on the order. All sets of blood cultures need to be submitted to the lab at the same time, multiple bags can be fastened together, with a “CAB INVESTIGATION” label attached.

Blood cultures for Candida species
No additional procedures are required for the routine isolation of Candida species from the blood.

Blood cultures for the fungal organisms Histoplasma capsulatum, and Blastomyces dermatitidis
Please refer to Laboratory Test Information Guide: Blood culture - Malassezia species, Histoplasma capsulatum, and Blastomyces dermatitidis.

Blood sampling volume
For optimal test sensitivity in adults, each bottle should be inoculated with 8 – 10 mL of blood per bottle. If less blood is obtained, it should still be submitted to the lab for processing.

*Caution* There is a strong draw on these bottles. Do not overfill or underfill.
Red top bottles have special gases inside; do not vent or introduce air from the syringe into the bottle.

Site selection
Each blood culture set should be drawn from a different draw – 2 different venipuncture sites OR 1 venipuncture site plus 1 central line site.

Central lines
For the purpose of blood culture collection, the initial draw (‘waste’) from a central line may be used in the collection process for the purpose of blood culture.

For central lines with multiple lumens, it is recommended to either draw from each lumen (and record in EPR the lumen sampled) or pool blood from multiple lumens into one blood culture bottle. Regardless of the chosen procedure, each lumen should be sampled.

Each adult blood culture set (2 bottles) must have a new order with a separate distinguishable accession number. Affix one large collection label to each of the bottles in the space provided at bedside.

Send all remaining labels in the specimen bag with the blood culture bottle/set.
Place labels vertically. Do not cover the bottle bar code. Transport as directed.

Additional information can be found at: Blood culture collection procedure – Labelling and Transport.

Collection procedures
Please refer to the blood culture collection procedures:
Blood culture collection procedure – Adult, Venipuncture
Blood culture collection procedure – Central line
Test Schedule: Daily
Turnaround time from when specimen
is received in testing laboratory:
5 days – positive findings are available within 1 hour of discovery. Negative cultures at 24 hours
Reference Range: 5 days – positive findings are available within 1 hour of discovery.

Negative cultures at 24 hours will be routinely updated with the comment “No growth 1 day”
Effective Date: 2018-04-09
Revised Date:  
Critical Value:  
Interpretive Comments: Recovery of organisms depends mainly on volume of blood collected and frequency of collection. Timing is less important, particularly if cultures are collected before antimicrobial therapy.
Special Processing:  
Method of Analysis: Continuous monitoring blood culture system
Critical Information Required:  
Storage & Shipment: Transport bottle to the lab promptly; all bottles must be received within 24 hours of collection.

If there is a delay in transport, bottles can be left at room temperature. Never refrigerate. Additional information can be found at: Blood culture collection procedure – Labelling and Transport.
System Codes: 
Referred To:  

Questions? Comments? Contact Laura Gopaul