Strict asepsis. So important to do this right as a skin contaminant can end up with a patient having to stay on prolonged antibiotics for a blood infection they don't have
- Blood cultures often done as part of a sepsis screen along with urine culture, chest X-ray, sputum culture and further serology as part of a septic screen.
- Indicated when a patient has had a fever, rigors, sweats, delirium, other signs of sepsis. Some patients with bacteraemia may not be febrile
- Send Two bottles one is prepared for aerobes and the other anaerobes.
- Very good skin asepsis is needed with chlorhexidine or alcohol to avoid contamination with coagulase-negative Staphylococcus spp. (such as S. epidermidis).
- Only 5 mL of blood is needed for each bottle, but more than 20 mL is preferred to increase your chance of culturing any circulating bacteria.
- The aerobic container is the more important if blood limited.
- Label the bottles but do not cover barcodes and send them to the laboratory urgently.
- Peel off the miniature barcode and apply to the patient medical records.
- Oncology and Haematology patients may have long-term vascular access such as a central venous catheter (CVC) or port so attempt to send off one set of cultures drawn through this site, and one elsewhere (e.g. a peripheral upper limb vein).
- The more cultures taken, the higher the yield supported best by studying cases of infective endocarditis, where a minimum of three cultures (more if you can) should be sent BEFORE antibiotics given.
- Cultures results take at least 24 hours even longer
- Microbiology may call you to notify you of a positive culture.
- False positives are not uncommon and take expert advice
- Wash hands, ensure name badge visible
- Introduce yourself, ensure correct patient
- Ask if you may take a blood sample
- Explain why it is necessary
- Ensure verbal consent obtained
- Sterile Gloves, Tourniquet, Alcohol wipes or equivalent
- Green needle and syringe and vacutainers
- Place tourniquet around the upper arm and wait until veins dilated
- Find a decent vein often in the forearm
- Clean the skin with several alcohol wipes - some say up to 5
- Avoid touching the skin again
- Insert the needle into the vein and watch for flashback
- Fill the syringe and inject into culture bottles
- Before removing the needle release the tourniquet
- Remove the needle and apply pressure with a cotton wool ball or gauze
- Wait until haemostasis achieved and apply plaster if needed
- Thank patient
- Dispose of sharps
- Label bottles at bedside with patient identifiers
- Answer any questions from patient
- Failure: try 2-3 times and if failing ask for help or come back later
- Haematoma: usually because needle removed from a vein before tourniquet removed
- Arterial puncture: remove needle and apply pressure