Blood Culture

Blood culture opener.jpeg

This module describes how to draw blood under sterile conditions and inoculate into a culture medium for microbiological investigations, when suspecting bacteraemia or sepsis.


  1. Features of

  2. Certain localised or systemic infections that could cause bacteraemia/fungaemia such as infective endocarditis, meningitis, septic arthritis, or systemic fungal infections

  3. Intravascular

    bloodstream infections

  4. In some cases to monitor the efficacy of antimicrobial treatment


  1. Damaged skin, swelling, sclerosed veins, haematomas or skin infection at the drawing site
  2. AV fistula or IV cannula site on the same limb

Always verify your patient’s identity and obtain informed consent before proceeding.

How do I explain this procedure?

“I need to draw blood from you to test for infections.”

What can my patient expect?

“You may feel a sharp sting when I insert the needle. This blood test may take a little longer than usual blood tests and I may need to take blood from two or three places. Afterwards, the test results can take several days.”

What is my patient’s role?

“Let me know if you have any allergies or a bleeding tendency, or use blood thinners. Fearing blood or needles is normal, but tell me if you have fainted from it. Everything must stay very clean to do this test. Keep as still as possible, and don’t cough, sneeze or reach over the equipment. Don’t touch the top of the paper I put over the area. Afterwards, press firmly on the area with cotton wool to prevent bleeding.”


Prepare a trolley with equipment.

Blood Culture Opener 2

Documentation

  1. Laboratory request form
  2. Patient labels
  3. Patient notes

Equipment

  1. Sterile gloves

  2. Alcohol-based hand rub

  3. A sterile pack (preferably a blood culture pack)

  4. Tourniquet

  5. Blood culture

  6. A 22 G or larger

  7. A

  8. An alcohol swab

  9. Cotton wool and a plaster

  10. Laboratory specimen bag


See Venous Blood Sampling, or if no venous sites found, Arterial Blood Sampling.

Venous blood sampling Site.jpeg


Follow medical asepsis with sterile gloves.

  1. Open the sterile pack and create a sterile field on a

    , dry surface. Pour skin disinfectant into the well. Open the needle and syringe onto the sterile field.

  2. Flip the lid off the blood culture bottle,

    with an alcohol swab, and place it beside the sterile field.

  3. Secure the tourniquet above the chosen puncture site.

  4. Perform hand hygiene and don sterile gloves.

  5. Clean the puncture site. Allow to dry.

  6. Drape the puncture site with the

    from the sterile pack. You may touch the whole sheet.

  7. Attach the needle to syringe and draw at least 10 ml of blood. Uphold principles of sterility.

  8. Release the tourniquet with your non-dominant hand before withdrawing the needle. Your non-dominant hand is now non-sterile.

  9. Use your non-sterile hand to apply gentle pressure with a dry cotton bud;

    the patient to take over.

  10. the bottle. If you have other tubes to fill, fill them afterwards.

  11. Dispose of medical waste safely.

  12. Secure the cotton bud with a plaster if the site is still bleeding.

  13. Rotate the bottle gently.

    and transport it to the laboratory in a specimen bag with the laboratory request form.

  14. Record completion of the procedure in patient notes.


I broke sterility.

Don’t risk contamination. Dispose of everything except the blood culture bottle, and start over.

Something fell off my sterile field and I’m gloved up.

Call for an assistant to collect the equipment and open it onto your sterile field while you wait. If nobody is available, collect the equipment yourself, then put on a new pair of sterile gloves and continue.

I couldn’t get a full 10 ml of blood.

You need a full 10 ml of blood. Don’t try to take a little more from another site and put it into the same bottle. Start over completely at a new site with a new bottle.

I want to use a femoral site for blood culture.

Only as a last resort, as these sites have a higher risk for contamination than upper limb sites. Be especially meticulous about skin antisepsis when using these sites.

Also see Venous Blood Sampling and Arterial Blood Sampling.


  1. caused by specimen contamination

  2. caused by inadequate sampling


  1. Fabre V, Sharara SL, Salinas AB, Carroll KC, Desai S, & Cosgrove SE. Does This Patient Need Blood Cultures? A Scoping Review of Indications for Blood Cultures in Adult Nonneutropenic Inpatients. Clinical infectious diseases: an official publication of the Infectious Diseases Society of America. 2020;71(5):1339–1347.
  2. WHO Guidelines on Drawing Blood: Best Practices in Phlebotomy. Geneva: World Health Organization; 2010. Available from: https://www.ncbi.nlm.nih.gov/books/NBK138665/.
  3. Ntusi N, Aubin L, Oliver S, Whitelaw A, Mendelson M. Guideline for the optimal use of blood cultures. S Afr Med J. 2010;100(12):839-843. Published 2010 Dec 1. doi:10.7196/samj.4217