What is the most important consideration when collecting a blood culture?

Collection Procedure:

Policy Tech: Version 10

Special Notes: To prevent specimen contamination by microorganisms, use sterile supplies and
aseptic technique to collect specimens. Obtain cultures prior to starting antibiotic therapy. Notify the
physician if unable to obtain cultures.

Equipment: venipuncture needle, syringe for specimen, chlorhexidine frepp, tourniquet, gauze,
adhesive bandage

Blood Culture Media always consider patient’s weight when choosing appropriate bottles
Green Aerobic Bottle FA+: 1 ml minimum to 10 ml maximum (See Weight Chart)
Orange Anaerobic Bottle FN+: 2 ml minimum to 10 ml maximum (See Weight Chart)

Collection Procedure:

1. Clean venipuncture site with chlorhexidine frepp using back and forth friction scrub for 30
seconds. Allow it to dry for 30 seconds.

2. Do not retouch site; if you must repalpate for vein, the area must be recleaned using above
procedure. Perform venipuncture.

3. When required amount of blood is received, remove needle from skin.

4. Hold pressure to site with gauze and apply adhesive bandage when bleeding stops.

5. Remove venipuncture needle from syringe and attach blunt fill needle and transfer device.

6. Remove tops of blood culture bottles and swab with chlorhexidine.

7. Inject blood specimens into bottles, place specimen into the anaerobic Orange bottle, then
the aerobic Green bottle. If you only have enough blood for one bottle, place the specimen
in the aerobic Green bottle. Be careful, the bottles are pressurized and will aspirate all of
the blood from the syringe unless you control the flow with your thumb and index finger.
Optimal blood amounts are necessary or you will have decreased sensitivity which may
delay time to detection of a true positive blood culture.

8. Label bottle. Indicate whether line draw or peripheral. Label specimens with at least two

patient identifiers, such as name, medical record number, and date of birth

9. Discard needle and syringe into a sharps container

10. Send specimen promptly to CCL. If the specimen is coming from the floors, send the audit
trail with specimen that includes initials of person drawing the specimen, date, time and
venipuncture site.

References:

Bowden, V.R., Smith Greenberg, C.(2008). Pediatric Nursing Procedures, 2nd Ed. Philadelphia:
Wolters Kluwer/Lippincott Williams & Wilkins.

Isenberg, H.D. (2004). Clinical Microbiology Procedures Handbook, Volume 2. Washington, D.C.:
The ASM Press.

Package Insert BacT/Alert FA+ Ref 410851. 04/2016

Package Insert BacT/Alert FN+ Ref 410852. 04/2016

Blood cultures are one of the most important laboratory tests performed in the diagnosis of serious bloodstream infections (bacteremia or fungemia).

However, needlestick injury and sample contamination remain major issues for health care organizations and laboratories that collect and process blood culture samples.

Best practice blood culture procedures involve careful consideration of specimen collection, processing and subculture techniques.

In this article we’ve looked at blood culture collection guidelines and subculture procedures that aim to protect laboratory staff and improve patient outcomes.

Why are blood cultures important?

Without detection through blood cultures and subsequent treatment, a bloodstream infection can progress to its most severe stage — sepsis.

According to the Mayo Clinic, while most people recover from mild sepsis, the average mortality rate for septic shock is still about 40%.

Early identification of bloodstream infections through blood cultures is a key step in ensuring appropriate treatment for the patient.

Importantly, beginning effective antibiotic therapy as early as possible can have a dramatic impact on the outcome of the infection.

How to safely collect blood cultures

Diligent sample collection is a critical step in the blood culture process because poor technique can lead to contamination and/or needlestick injury.

Thousands of US healthcare workers are affected by needlesticks each year, and collection and then transferring blood samples between containers is a hazardous practice for potential sharps injuries.

It’s also been well-documented that improper collection techniques can lead to contamination of blood culture samples, which can result in the need for repeat testing, increased hospital costs, and health system inefficiencies.

Managing positive blood cultures

If the blood cultures are positive for bacterial growth, subcultures are initiated to provide further information to the clinician that will help determine the appropriate antibiotic treatment.

The subculture process is typically done by using a needle and syringe or a venting needle to transfer sample from blood culture bottles onto media plates and slides. This can pose the threat of accidental needlestick injury to the technologist at multiple stages in the procedure including:

before the needle is inserted into the culture bottle
during needle insertion into the culture bottle
after the needle is removed from the bottle.

With distractions and heavy workloads, accidents can easily happen. However, safer products have been developed to transfer samples from culture bottles, including needleless systems.

Having a safer subculture system that allows for needleless transfer of samples from culture bottle to plate limits the chances of needlestick injury and staff exposure to culture discharge.

ITL BioMedical manufactures a range of blood culture sampling and transfer devices for hospitals, clinics and laboratories.

Find out more

Background:

Properly obtained blood cultures are important to identify organisms and to ensure proper antimicrobial/antifungal coverage while minimizing false positive results.

Principle

Preparation of the skin for venipuncture is important to prevent contamination of blood cultures by bacteria that normally lie on the skin and to prevent introduction of these bacteria into the patient's bloodstream.

Patient Identification:

Follow the HFHS Patient Identification Policy (HFHS Administrative Policies - Clinical Practice) to properly identify the patient. Follow the Department of Pathology specimen labeling policy to properly label each bottle with patient identification and collect time and date before the blood is drawn.

Specimen Logistics

Blood cultures should be drawn prior to initiation of antimicrobial therapy.

Preparation of skin prior to blood culture collection is important to prevent contamination of sample.

At least two (2) sets of blood cultures should be obtained (each set includes one (1) aerobic and one (1) anaerobic bottle).

Each set of blood cultures are to be drawn from two separate venipuncture sites at approximately 15 minutes apart.

If two separate venipunctures are not able to be drawn, the provider must be notified, and collaboration should be done to determine if two sets are necessary.

Central lines (includes dialysis lines and Mediports) and Peripherally Inserted Central Catheters (PICCs) should not be used to obtain blood cultures due to the high probability of colonization and the likelihood of false positive results.

Central lines from outside facilities may be cultured for up to two (2) calendar days (as opposed to 48 hours), after admission by provider order only for a positive blood culture to be considered present on admission.

Blood culture volume is essential. There is a 3% increase in sensitivity for every extra mL collected. Blood culture bottles require 8- 10 mLs. to be accurate.

After positive blood cultures have been identified wait at least 48 hours to draw any additional blood cultures.

Surveillance blood cultures should not be routinely done.

KEY POINT: Neutropenic (ANC < 1500 µL) or thrombocytopenic (Platelets < 30,000 µL) patients suspected of having a blood stream infection are to have peripheral blood culture attempted twice before considering drawing a blood culture from a central line or PICC. It is imperative that cultures in these patients are drawn within an hour of suspected infection has been identified.

Do not send catheter tips for culture.

Escalation order of blood culture sites, General Practice Unit:

Peripheral venipuncture
Hospital Expert/IV team
Arterial puncture by Rapid Response team (if available)
Notify provider.

Escalation order for blood culture sites, Intensive Care Unit:

Peripheral venipuncture
Arterial Puncture
Unit Expert
Arterial line
Hospital Expert/IV team
Notify provider.

Procedure:

Gather equipment:

Tourniquet
70% alcohol swab
2% Chlorhexidine with 70% isopropyl alcohol applicator
Aerobic and anaerobic blood culture bottles
Vacuette
Butterfly set
Clean Gloves
Dressing
Pen
Labels

Prepare the blood culture bottles:

Remove cap and scrub the top of each blood culture bottle with a separate alcohol swab for 30 seconds
Allow to air dry
- Do not fan or blow on tops once scrubbed.
- Do not touch tops once scrubbed.

Patient preparation

Explain the procedure to the patient
Perform hand hygiene
Place tourniquet
- Tourniquet should not remain on patient for longer than 1 minute
Palpate and select site prior to cleansing skin
Remove tourniquet

Obtain the Culture: Collect using butterfly set and vacuette

Assemble blood culture drawing equipment and arrange supplies needed.
Perform hand hygiene.
Put on clean gloves.
Place tourniquet.
Cleanse skin with 2% Chlorhexidine with 70% isopropyl alcohol applicator for 30 seconds using back and forth scrubbing technique
- Allow to dry for at least 30 seconds (skin must be dry prior to venipuncture).
- Do not fan or blow on skin once cleansed.
- Do not palpate site once cleansed.
Perform venipuncture. Venipuncture should be performed using butterfly set and vacuette.
Fill aerobic bottle first then anaerobic bottles (Appendix A for correct volume appropriateness).
Fill until 10mLs is obtained in each bottle. Watch volume as bottle may overfill.
Remove tourniquet.
Hold pressure and place dressing.
Remove gloves.
Perform hand hygiene.
Label cultures with bedside labeling device or handwrite the site of draw on label while at the patient’s bedside. (See Appendix B).
Send to lab per operational unit policy.

Drawing Blood Cultures from vascular access device (VAD):

Blood should not be drawn from a VAD unless line related sepsis is suspected. Confirm that MD's order for blood culture specifies a line draw. Blood cultures drawn from lines are more likely to be contaminated therefore adequate precautions should be taken to avoid contamination. If drawing a blood culture from a VAD, it should always be accompanied by a blood culture from peripheral site.

See appropriate nursing guidelines for drawing blood from VADs. Follow instructions for bottle preparation and blood culture volume as outlined previously. Use alcohol prep to scrub hub connection with 70% alcohol and allow to air dry. Bottle cannot be drawn directly without the use of an adapter. Contact laboratory is assistance is needed.

If unable to obtain peripheral blood culture and a culture from an IV line needs to be done, these steps must be followed for drawing blood cultures from peripheral IVs, Central Lines and PICCs:

Remove needleless connector and place a new sterile one
- Never draw from an old connector
Scrub the hub with 70% alcohol swab for at least 30 seconds and allow to dry
- Do not fan or blow on connector once cleansed
Contact lab for any additional adapters as bottle cannot be drawn directly from site.
Do not draw more than one set from this access
If another set is needed wait 15 minutes change needless connector and repeat the process

Number and Timing of Blood Cultures

Condition	Recommendations
Suspected acute primary bacteremia or fungemia, meningitis, osteomyelitis, arthritis, or pneumonia	Obtain 2 sets at the same time by separate venipuncture immediately following the clinical events that precipitate the blood culture.
Fever of unknown origin	Obtain 2 to 3 blood culture sets initially at the same time by separate venipuncture. Then, 24 to 36 hours later, obtain two more sets of cultures immediately before the expected (usually afternoon) temperature elevation.
Suspected bacteremia or fungemia with persistently negative blood cultures	Consider alternative blood culture methods designed to recover rare or fastidious microorganisms (e.g. Isolator tube)
Infective endocarditis	Obtain 4 blood culture sets during the first 1-2 hours of evaluation. If all are negative 24 hours later, obtain 4 more sets. From patients who have received antimicrobial agents within 2 weeks prior to admission, obtain two separate blood cultures on each of three successive days. Request extended incubation if Brucella or Bartonella is suspected.

Transport to the Lab

Pneumatic tube: To send blood culture bottles by pneumatic tube, place each bottle in a biohazard bag. Seal the bags and place the requisition slips (if not preordered) in the outside pocket of one of the bags. Place the bottles in the carrier so that the bottoms of the bottles are end to end in the center of the carrier and the necks of the bottles face outward. Other specimen tubes may be placed in the carrier with the blood culture bottles as room permits.

Regular courier: Use two specimen bags. Wrap one bottle snuggly with a plastic specimen transport bag and insert the wrapped bottle in another plastic transport bag. Place the second bottle of the set in the bag. Seal the bag and place requisition slips (if not pre-ordered) in the outside pocket.

Instructions for local laboratory sending blood cultures to Core Microbiology laboratory

If there is no scheduled courier within 4 hours of blood culture receipt in the laboratory, contact A1 cab for transport to core laboratory. This may require calling A1 cab more than once per day for blood cultures particularly during large gaps between scheduled courier runs. Use of A1 cab for specimen transport can be minimized by strategically scheduling A1 use (example: schedule A1 cab to arrive in the middle of an 8 hour gap between scheduled courier runs). If A1 is contacted to pickup blood culture specimens, any additional microbiology specimens pending transport should also be sent along with batch list.

Reference(s)/Source(s):

Clinical Key “Blood specimen collection: Blood cultures” accessed 7/12/18.

Wiggers JB, Xiong W, Daneman N. Sending repeat cultures: is there a role in the management of bacteremic episodes? (SCRIBE study). BMC infectious diseases. 2016 Dec; 16(1):286.

Wilson ML, Mitchell M, Morris AJ, Murray PR, Reimer LG, Reller LB, Towns M, Weinstein MP, Wellstood SA, Dunne JW, Jerris RC. Principles and procedures for blood cultures; approved guideline. CLSI document M47-A. Clinical and Laboratory Standards Institute, Wayne, PA. 2007.