Blood Culture

Blood Culture Aerobic/Anaerobic

Microbiology

CBL

BLOOD CULTURE SETS Two sets of blood cultures from separate venipuncture sites, drawn within a 24 hour period and prior to antibiotic therapy, are recommended. If endocarditis is suspected, collect a third set. Venipunctures at least 30 minutes apart is the preferred method. Adult sets -consists of 1 aerobic bottle with a green flip cap and 1 anaerobic bottle with a orange cap. Second set consists of one aerobic bottle.

(3 bottles in total).

Pediatric collection -consists of a single bottle that has a yellow cap. Two bottles should be collected. ** See note below**

Check the expiry date, on the container prior to use. There is a growth sensor in the bottom of the bottle. The sensor should be olive green, this also should visually be inspected prior to use. Gradations on the side of the bottle may help to measure volume of blood being introduced.

IMPORTANT Bottles for adults should be inoculated with 8 to 10 mL per bottle. *Caution* - there is a strong draw on these bottles. DO NOT EXCEED the maximum 10 mL per bottle.

Pediatric bottles should be inoculated with 2 to 4 mL.

**Although the optimal conditions indicated above comply with best practice and manufacturer guidelines, it is recognized that with premature babies and other newborns it may not always be possible to perform more than one collection. In this case, it is imperative that the one bottle collected has the required minimum volume of 2 ml as the incidence of false negative results is high with the low volume collection***

In any venipunture the blood cultures are always the first collected.

Blood Culture Bottles

(also known as BacT/Alert bottles)

Aerobic Anaerobic Paediatric

Blood can be collected by venipuncture or intavascular catheters

Site selection - Select a different site for each culture drawn. Avoid drawing blood through indwelling catheters unless blood cannot be obtained by venipuncture or if diagnosis of catheter sepsis is suspected. (Do not palpate the vein without gloves on)

Wash hands and don gloves.

Apply tourniquet.

Site Preparation - select vein appropriate for venipuncture. After selection has been made, remove tourniquet and cleanse the venipuncture site with the 0.5% chlorhexidine-70% isopropyl combination swab in a circular motion from the center of the puncture site outward covering a circular area of 1 1/2 to 2 inches in diameter for a minimum of 30 seconds. Allow to air dry and do not touch after cleansing.

Culture Bottle Preparation - Flip cap off. Clean rubber septum with 70% alcohol. Allow to dry.

Indicate on the blood culture label 10ml mark from the level of the media in each bottle prior to attempting collection. Blood will then be collected to this line.

Clean tops of any other tubes to be collected.

Vacutainer Collection - This method is preferable for adults.
Perform venipuncture and collect vacutainer specimens for other tests first using adapter cuff. Use of insert is optional. Collect blood culture bottles. Inoculate aerobic bottle first so as not to introduce air into the anaerobic bottle which is inoculated second.

Butterfly Needle Set - Preparation of site and bottles is the same as for vacutainer collection. Collect blood culture bottles.

Needle/Syringe System - This method is preferred for children. Preparation of site and bottles is the same as for vacutainer collection. Collect blood in syringe, change needles and inject up to the pre-marked lines on the bottles. Inoculate aerobic bottle first so as not to introduce air.

Gently mix bottles to avoid clotting.

Labeling - Both blood culture bottles in the set must have the same collection number. Affix one large collection label to each of the bottles in the space provided. Do not cover the bottle bar code. Send all remaining labels in the specimen bag with the blood culture set.

Initial the barcode labels and affix to bottles. Indicate the time of collection on the lead label.

Apply band aid to venipuncture site.

Dispose of any collection system needles in accordance with standard precautions. Adapter cuffs and inserts are not disposable. Clean and sterilize these by disinfecting in bleach.

Remove gloves and wash/disinfect hands between each patient.

Transport to laboratory promptly.

Second set to be collected 30 minutes later.

Daily

Positives are reported to designated health care provider upon detection.

Cultures are incubated for 5 days.

The blood culture instrument used for detection of bacterial growth monitors the samples once every 10 minutes. Gram stain will be performed when growth is indicated.

Recovery of organisms depends mainly on volume of blood collected and frequency of collection. Blood cultures should be collected prior to antimicrobial therapy.

A single set should be discouraged as it is difficult to interpret results.

When drawing simultaneously from an indwelling cather/PICC and a peripheral site. A complete set is draw from the line (1 aerobic bottle with a green flip cap and 1 anaerobic bottle with a orange cap) and a single aerobic bottle is drawn from the peripheral site.

The specimens should be transported as soon as possible to the lab.

On site, BGH laboratory