Blood culture collection requires a meticulous aseptic technique to prevent contamination and ensure accurate results.
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Locate the Vein: Identify an appropriate venipuncture site.
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Prepare the Site with Antiseptic: This is the most critical step.
- Remove the Frepp™ applicator (or equivalent Chlorhexidine Gluconate and Isopropyl Alcohol antiseptic applicator) from its packaging.
- Apply the sponge of the applicator to the selected venipuncture site. Depress the applicator once or twice to saturate the sponge with antiseptic solution.
- Scrub the site vigorously with a back-and-forth friction motion for at least 30 seconds. The mechanical action is crucial for disrupting the skin flora.
- Allow the prepared area to air dry completely for approximately 30 seconds. Do not wipe away the antiseptic.
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Collection of Blood:
- Using sterile technique, insert the needle into the vein.
- Collect the blood directly into blood culture bottles. Use the correct fill volume for each bottle, as indicated on the bottle label. Typically, two bottles are used: one for aerobic (with oxygen) bacteria and one for anaerobic (without oxygen) bacteria. The order in which you fill the bottles may vary based on institutional guidelines and the collection system.
- Inoculate the aerobic bottle first unless a butterfly needle set is being used. If using a butterfly, inoculate the anaerobic bottle first to avoid air entering.
- Mix the blood gently with the culture media in the bottles by inverting the bottles several times. Do not shake vigorously.
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Post-Collection:
- Apply pressure to the venipuncture site until bleeding stops.
- Apply a sterile bandage.
- Label the blood culture bottles with the patient's information, date, time of collection, and the collector's initials.
- Transport the blood culture bottles to the laboratory promptly.
Important Considerations:
- Contamination: Skin contaminants are a major cause of false-positive blood cultures. Strict adherence to aseptic technique is essential.
- Volume: Collecting the correct volume of blood is crucial for optimal bacterial detection. Underfilling or overfilling the bottles can affect the results.
- Timing: Blood cultures should be drawn before antibiotic administration whenever possible. If the patient is already on antibiotics, blood cultures should be drawn just before the next dose of the antibiotic.
- Multiple Sets: It is common to collect two or three sets of blood cultures drawn from separate venipuncture sites to improve the sensitivity of detection and help distinguish true bacteremia from contamination. These should be drawn within a short time frame (e.g., within 30 minutes).
