Blood culture collection – OSCE guide

Taking blood cultures is a relatively common OSCE station.  You’ll be expected to demonstrate your clinical skills and ability to communicate effectively. This blood culture collection OSCE guide provides a clear, concise, step by step approach to obtaining blood cultures. There is wide variation in the type of equipment used for obtaining blood cultures and therefore you should always follow your medical school or local hospital’s guidance. You should note however that blood cultures should ALWAYS be obtained via a fresh stab and not use existing peripheral lines. If a patient has a central line blood may be taken from this if investigating a source of infection where the line is a potential source, however this should be done in combination with a peripheral sample (which should be taken first).

Introduction

Wash hands

Introduce yourself

Confirm patient details – name / DOB

Explain procedure:

“I need to take a blood sample, which will require inserting a needle into your vein.“

“It will feel like a sharp scratch and shouldn’t take too long.“

“The sample is to look for any infection in the blood.“

Gain consent – “Do you understand everything I’ve said?” “Are you ok for me to go ahead?“

Gather equipment

Collect all equipment needed for the procedure and place it within reach on a tray or trolley, ensuring that all the items are clearly visible.

• Clean procedure tray
• Apron
• Non-sterile gloves
• Tourniquet – single use
• Blood sampling device with blood culture bottle adapter (e.g. winged blood collection set)
• Blood culture bottles x 2 (anaerobic & aerobic)
• Sharps container
• Cleaning swab x 3 (2% chlorhexidine in 70% isopropyl alcohol)
• Sterile gauze
• Sterile plaster
• Tape
• Laboratory forms, labels and transportation bag

Preparation

Ensure the patient is lying or sitting comfortably – place a pillow under their arm if possible.

1. Prepare blood collection set using aseptic non-touch technique (ANTT)

2. Position the patient’s arm in a comfortable extended position that provides adequate exposure of the planned venepuncture area

3. Inspect the antecubital fossa or forearm for a suitable vein (it should ideally be visible without applying the tourniquet)

4. Apply the tourniquet about 4-5 finger widths above the planned venepuncture site

5. Palpate the vein:

• Choose a vein has a sizeable lumen and feels “springy”
• Tapping a vein gently can make it easier to visualise and feel

6. Thoroughly clean the site:

• Use 2% chlorhexidine in 70% isopropyl alcohol to disinfect the patient’s skin and allow to dry
• If the patient’s skin is visibly soiled use soap and water to clean the site
• Once the skin has been disinfected you should not touch the site again (even with gloves on)

7. Wash your hands:

• Using alcohol gel and the World Health Organisation’s hand hygiene technique show in our guide here
• If your skin is visibly soiled you should wash your hands using soap and water

8. Don apron and gloves

9. Remove caps from the blood culture bottles immediately prior to taking the sample and clean the top of each with a separate cleaning swab, allowing the alcohol to evaporate for 30 seconds before proceeding with bottle inoculation.

10. Place the sharps bin and equipment tray (containing your sample bottles, gauze and plaster) within easy reach in preparation for venepuncture.

Insertion of the needle

1. Prepare the blood collection system using ANTT (some blood collection systems require some assembly such as attaching an to the needle)

2. Unsheathe the needle

3. Anchor the vein from below with your non-dominant hand by gently pulling on the skin distal to the insertion site

4. Warn the patient of a sharp scratch

5. Insert the needle through the skin at a 30 degree angle or less, with the bevel facing upwards (you should feel a decrease in resistance as the needle enters the vein)

6. Advance the needle a further 1-2 mm into the vein after the decrease in resistance is felt

7. Lower and anchor the needle to the patient’s skin

8. Use the other hand to attach the aerobic blood culture bottle to the adapter, piercing the blood culture septum and allowing the bottle to fill with 10ml of blood (using the bottle’s graduation lines to accurately gauge sample volume)

9. Remove the aerobic bottle and then attach the anaerobic bottle, also filling it with 10ml of blood

10. Release the tourniquet

11. Withdraw the needle and then apply gentle pressure to the site with some sterile gauze

12. Ask the patient to hold the gauze in place whilst you dispose of the needle into a sharps container

13. Apply a dressing to the patient’s arm (cotton wool / gauze / plaster)

14. Discard the used equipment into the appropriate waste bin 

To complete the procedure…

Thank patient

Wash hands

Fill out patient details on the sample bottles at the bedside

Send the blood samples to the lab for testing

Document the following in the patient’s notes:

• Reason for sample
• Time and date of sample
• Site the sample was obtained from
• Your name, signature and contact details

References

1. Taking blood cultures. A summary of best practices. UK Government Web Archive. Published 2011 [LINK]

2. WHO guidelines on drawing blood: best practices in phlebotomy. Published 2010. [LINK]

3. WHO Guidelines on Hand Hygiene in Healthcare: a Summary. Published 2009. [LINK]