Detection of pathogens causing bacteremia.

In adults, collection of less than 20 mL of blood per blood culture may result in false negative results. 

Blood culture bottles

Adult Blood Culture Volumes

Optimal culture collection is 10 ml in Plus Aerobic/F and 10 mL in Lytic Anaerobic/F (20 mL total). The aerobic (blue) culture bottle should be collected first to ensure adequate volume in the optimal bottle type.  Using this method, it is better to fill one aerobic bottle with the maximum amount of blood, rather than submit two bottles with suboptimal volume in each.

Pediatric Blood Culture Volumes

*  Less than 1 mL blood accepted, but not optimal, in patients less than 4 years of age. Note volume drawn on bottle. “Suboptimal low volume blood cultured” comment added to report.

The blood volume cultured is crucial for detection of organisms. Collect the optimum volume listed if possible. Culturing lower volumes may result in false negative results.

Allina Health recommends two (2) blood culture sets be collected from two (2) different peripheral sites with no delay between draws. Utilization of a diversion device for blood culture collection can reduce false positives and is recommended.

EACH BLOOD CULTURE SET MUST BE A SEPARATE VENIPUNCTURE. EACH SITE MUST BE PREPARED INDIVIDUALLY, even if more than one blood culture is to be drawn at the same time.

1. Remove FLIP OFF cap of each bottle.
2. Sterilize the exposed rubber septum using a 70% alcohol prep.
3. Apply tourniquet to patient's arm and select vein.
4. Prepare venipuncture site.
   1. Hold the ChloraPrep SEPP applicator with sponge tip facing downward and gently squeeze to break the ampule. Do not touch the tip.
   2. Saturate the tip with ChloraPrep by gently pressing it against the treatment area.
   3. Using a back and forth friction scrubbing motion, completely wet the treatment area for 30 seconds.
   4. Allow the prepped area to dry completely, approximately 30 seconds.

Do not blot or wipe the solution away, or fan or blow on the site, as this may result in contamination of the blood culture.

5.  Discard the applicator after a single use.

6.  Blood must be drawn with a syringe and butterfly or a syringe and needle. The vacuum in the Bactec bottles is not predictable and the volume markings on the bottles are inaccurate, so do NOT draw the blood directly into the bottle.

SPS vacutainer tubes or Isolator tubes should NOT be used to draw the blood, as the additional anticoagulants in these tubes may be detrimental to organism recovery.

7. After the venipuncture site has been disinfected, the vein may not be palpated again. If further palpation of the vein is necessary during aspiration, a sterile glove should be worn.
8. Withdraw 20 mL blood.

For pediatric patients, see Pediatric Blood Culture Volume chart.

9. Release tourniquet, place gauze on the needle, and withdraw the needle from the vein while gently compressing the gauze.
10. DISCARD NEEDLE AND ATTACH BD BLOOD TRANSFER DEVICE TO SYRINGE. (Utilize one Transfer Device to inject both bottles.)
11. Inject 10 mL of blood into the Lytic Anaerobic/F bottle first to prevent entry of air from the syringe. Then inject 10 ml of blood into the Plus Aerobic/F bottle.

Inoculation of greater than 10 mL blood into the Aerobic or Anaerobic bottle or more than 4 mL into the Peds Plus/F bottle may result in suboptimal blood to media ratios and possible false negative results.

12. After thoroughly mixing contents by gently inverting bottles, label the bottle with two  unique patient identifiers, time of collection and site
    1. Do NOT cover sensor on bottom of bottle.
    2. Do NOT cover or write over teh bottle barcode.

Blood culture bottles

Ambient (strict) - 48 hours

Refrigerated - NO

Frozen - NO

• Improper label (unlabeled or mislabeled)
• Time delay between time of collection and receipt of specimen
• Improper transport container
• Improper transport temperature
• Inappropriate specimen type
• Leaking container

Culture

No growth

Identification, susceptibilities and serogrouping will be performed on all microbiology isolates considered by the laboratory to be significant