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Table of Contents
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This venepuncture guide provides a step-by-step approach to performing venepuncture in an OSCE setting, with an included video demonstration. The guide discusses venepuncture using vacutainer bottles, so steps may differ if you are using different equipment (e.g. a needle and syringe).
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
Blood sampling device (e.g. butterfly needle and barrel): the size should be appropriate to the vein and sample requirements.
Blood specimen bottles
Alcohol swab (2% chlorhexidine gluconate in 70% isopropyl)
Gauze or cotton wool
Laboratory forms, labels and transportation bag
Wash your hands using alcohol gel. If your hands are visibly soiled, wash them with soap and water.
Don PPE if appropriate.
Introduce yourself to the patient including your name and role.
Confirm the patient’s name and date of birth.
Briefly explain what the procedure will involve using patient-friendlylanguage: “Today I need to take a blood sample, which involves inserting a small needle into your vein. You may briefly experience a sharp scratch as the needle is inserted.”
Gain consent to proceed with venepuncture.
Check if the patient has any allergies (e.g. latex).
Adequately expose the patient’s arms for the procedure.
Position the patient so that they are sitting comfortably. If a bed is available, the patient can lay down for the procedure (this is sometimes preferable, particularly if the patient is prone to vasovagal syncope).
Ask the patient if they have any pain before continuing with the clinical procedure.
Choosing an arm
1. Choose an arm to perform venepuncture on:
You should ask the patient if they have a preference.
Pre-existing medical conditions may prevent particular limbs from being used (e.g. arterio-venous fistula, lymphoedema, a stroke affecting the movement of a limb).
Do not perform venepuncture on an arm that has an intravenous infusion in progress as this may alter blood test results.
2. Place a pillow under the relevant arm.
Choosing a vein
1. Inspect the patient’s arm for an appropriate venepuncture site:
The median cubital vein in the antecubital fossa is commonly used for venepuncture.
Areas of broken, bruised or erythematous skin should be avoided.
Areas in which two veins join should be avoided where possible, as valves are often present.
2. Position the patient’s arm in a comfortable extended position that provides adequate access to the planned venepuncture site.
3. Apply the tourniquet approximately 4-5 finger-widths above the planned venepuncture site.
4. Palpate the vein you have identified to assess if it is suitable:
Tapping the vein and asking the patient to repeatedly clench their fist can make the vein easier to visualise and palpate.
An ideal vein feels ‘springy’. A vein that feels hard is likely sclerosed, thrombosed or phlebitic (inflamed) and should be avoided.
5. Once you have identified a suitable vein you may need to temporarily release the tourniquet, as it should not be left on for more than 1-2 minutes at a time.
6. Wash your hands again.
7. Don gloves (gloves don’t need to be worn for cleaning the site, but they should always be donned prior to performing venepuncture itself).
8. Clean the site with an alcohol swab for 30 seconds and then allow to dry completely for 30 seconds:
You should start cleaning from the centre of the venepuncture site and work outwards to cover an area of 5cm or more.
DO NOT touch the cleaned site afterwards at any point, otherwise, the cleaning procedure will need to be repeated prior to venepuncture.
Inspect the patient's arm for an appropriate vein
Medial cubital vein
Apply the tourniquet
Palpate the vein
Wash hands again
Clean the site for 30 seconds and allow to dry
Insertion of the needle
1. Re-apply the tourniquet if removed previously.
2. Attach the needle to the barrel (some blood collection systems come pre-assembled, such as the butterfly needle with barrel shown in the video).
3. Unsheathe the needle.
4. Anchor the vein from below with your non-dominant hand by gently pulling on the skin distal to the insertion site.
5. Warn the patient that they will experience a sharp scratch.
6. Insert the needle through the skin at a 30-degree angle or less, with the bevel facing upwards. You should see flashback into the needle’s chamber and feel a sudden decrease in resistance as the needle enters the vein.
7. Advance the needle a further 1-2 mm into the vein after flashback is noted to ensure you are within the lumen.
8. Lower and anchor the needle to the patient’s skin using the wings of the butterfly needle.
9. Attach each blood bottle, in the correct order of draw, to the barrel and allow them to fill to the appropriate level. Make sure to continue to anchor the needle to the skin as you remove each bottle from the barrel by gently pulling and twisting. If no blood begins to flow into the bottles, try slightly withdrawing or adjusting the angle of the needle.
10. Release the tourniquet.
11. Withdraw the needle and then apply gentle pressure to the site with some gauze or cotton wool.
12. Ask the patient to hold the gauze or cotton wool in place whilst you dispose of the needle into a sharps container.
13. Apply a dressing to the patient’s arm (e.g. cotton wool, gauze, plaster).
14. Invert each of the blood bottles the suggested number of times based on its colour.
15. Discard the used equipment into the appropriate clinical waste bin.
Unsheathe the needle and ensure the bevel is facing upwards
Anchor the vein from below using your thumb
Insert the needle at an angle of 30° or less
Observe for flashback, confirming you have punctured the vein
Anchor the needle to the patient's skin
Attach the sample bottles to the collection device
Release the tourniquet
Remove the needle and apply pressure to the site using gauze
Dispose of the needle into a sharps bin
Apply a plaster to the site
Remove apron and dispose of all clinical waste
Label the samples at the bedside
Seal the sample bottles in a bag and transfer to the lab for processing
Number of times to invert blood bottles
Inversion aids the mixing of a bloodsample with the bloodbottle’sadditives. The recommended number of times a blood bottle should be inverted differs depending on the blood bottle colour:
Light blue: 3-4 inversions
Gold/yellow: 5-6 inversions
Purple: 8-10 inversions
Pink: 8-10 inversions
Grey: 8-10 inversions
Blood tests and order of draw
Different bloodtests require different types of blood bottles to be used. In addition, blood bottles need to be filled in a specific order to both reduce the chance of sample contamination and improve the accuracy of results.
Below is a list of the common blood bottle types and the associated blood tests, organised by the recommended order of draw:
Blood culture: these bottles should always be attached first, with the aerobic sample preceding the anaerobic one.
*If your first bottle is light blue and you are using a butterfly needle you will likely need to use two of these blood bottles to obtain a full sample. This is because when you attach the first bottle it will draw in air from the tubing, resulting in a sample that is unable to fill with enough blood to reach the required level. To avoid this, you can initially attach a light blue blood bottle to remove the air (i.e. fill the tubing with blood), then detach this and fill a second blood bottle to the required level.