Venepuncture is the term used to describe the procedure of withdrawing blood from a vein using a needle. Consider the requirement for the procedure and establish appropriate levels of asepsis throughout.

Equipment

• Gloves
• Hand sanitiser
• Alcohol wipe
• Tourniquet
• Cotton wool/ gauze
• Needle (e.g. butterfly needle/green needle and syringe, or enclosed vacuum system)
• Syringe or vacutainer
• Blood specimen bottles
• Specimen bag
• Blood labels
• Plaster or micropore tape
• Access to a sharps bin

Procedure

1. Introductions, consent, handwashing, check patient ID and allergies (e.g. latex)
2. Apply tourniquet. Avoid an arm that has an intravenous infusion running as this may alter blood results.
3. Locate vein (try to feel for a plump vein rather than look).
4. Wipe the area with an alcohol swab and allow to dry (cleaning from the centre outwards, in circular motions).
5. With your non-dominant hand, anchor the vein distally
6. Using your dominant hand, insert the unsheathed needle into the skin at a 30 degree angle or less, with the bevel facing upwards. A visible flashback of blood into the needle means the needle has entered the vein
7. Attach bottles and fill. Note that blood samples are taken in the appropriate order of draw. Ensure you invert the bottle once filled to ensure adequate mixing
   • A butterfly needle with the relevant blood bottles may be used. Attach the blood bottle to the adapter at the distal end of the butterfly needle. In some trusts, the plunger attached to the blood tube may need manually withdrawn, creating a vacuum to allow blood to enter the blood tube. Please review local guidelines and equipment. Once appropriately filled, the blood bottle can be removed, and another attached depending on the bloods required. 
   • A butterfly needle with syringe may be used by removing the adapter at the distal end of the butterfly needle and attaching a syringe to the now free end of the butterfly needle. Once the vein has been pierced, slowly withdraw the plunger on the syringe to withdraw the necessary volume of blood required for blood sampling. Withdrawing the plunger of a syringe or blood bottle too fast may cause the vein to collapse. Decant the sample into the relevant blood tubes.
   • A simple vacuum system may be used by inserting a green needle into the vein and attaching the relevant blood sampling bottles in succession.
8. Remove tourniquet before removing the needle, applying pressure over the puncture site with cotton wool/ gauze. Once removed, dispose of the needle in the sharps bin.
9. Apply plaster or tape (ensuring the patient has no allergies)
10. Label the bottles at the bedside and check these details against the patient wrist band
    
    

• If you’re struggling, ask the patient where they normally have them taken from.
• Kneel or sit down
• Optimise patient positioning of the target limb (e.g. drop the arm from the side of the bed) to maximise gravitational blood pooling.
• If no blood begins to flow into the bottles despite a visible flashback, slightly retract or adjust the angle of the needle.
• In challenging cases, consider which of the blood results take precedence when filling the blood bottles and take these first. However, beware to ensure there is no EDTA contamination and appropriate order of draw is followed where possible.
• In challenging cases, consider the minimum blood volume required for each sample to be satisfactorily processed by the lab.
• On the contrary, if a patient is challenging to bleed on venepuncture, and a successful venepuncture is achieved, with good volumes and flow of blood, anticipate any future/upcoming blood samples that may be necessary and collect these samples during the current procedure.
• Don’t forget that you shouldn’t take blood from a patient where they’ve had breast surgery with lymph node clearance

Blood Cultures

Very similar to basic venepuncture, however it is imperative that you maintain an aseptic non-touch technique in order to not contaminate the sample and lead to a false result! This could lead to patients being erroneously treated.

Where possible, blood cultures should be taken prior to the commencement of antibiotic therapy, however, if antibiotics have already commenced, blood cultures may be taken just prior to the next antibiotic administration. Sampling two sets (i.e. 4 bottles) of blood cultures at different times and sites is good practice when not clinically contraindicated. This helps distinguish true positive results and sensitivities from possible contamination.

Equipment:

The same equipment as for venepuncture will be required, however anaerobic and aerobic blood culture bottles, 3 alcohol wipes, and a needle with blood culture bottle adapter will be required. These should replace the blood specimen bottles and venesection needle with adapter for standard blood bottles used in venepuncture. Some blood culture collection devices come pre-assembled, otherwise the barrelled adapter should be manually attached to the chosen needle. 

Procedure:

Is performed the same as venepuncture, however instead of attaching blood bottles as in step 7 above, attach the aerobic blood culture bottle, then once adequately filled, attach the anaerobic bottle. If blood samples are to be taken, this should be performed after obtaining blood cultures. Whilst the needle is in the vein and cultures have been collected, the barrelled adapter can be removed, and the blood tube adapter can be applied. The change of adapter is not required if a syringe is used to obtain the appropriate volume of blood directly from the needle used for venepuncture. If a syringe is used, ensure appropriate order of draw is followed, decanting into the aerobic then anaerobic culture bottle. Continue the remainder of the steps as the venepuncture guide above.

Things to remember:

• Remove the cap off the top of each bottle and wipe with an alcohol swab allowing to dry. You will need 3 swabs in total (one each for the bottles, one for the patient).
• You must wear gloves.
• Each bottle needs at least 10 ml of blood added
• You must fill the aerobic bottle first (think about it the needle/ butterfly have air inside therefore use the aerobic bottle first!)
• Most blood culture bottles have a sticker on the side with a unique number, either make a note of this number or put the stickers in the patient notes so that they can be tracked if needed.
• Always document that you took the cultures with aseptic technique (or if this was not possible, why not) and the site
  • If a patient has a central line, take cultures peripherally and centrally

Bloods from central lines

Always check your hospital policy about using central lines (including PICC) to take blood samples as not all trusts accept this or may advise different methods. If in doubt, the nursing staff may be able to advise you as they have a breadth of experience!

1. Introductions, consent, hand washing, check ID.
2. Choose a port (without any infusions or if possible stop the infusion then take the blood sample >130 mins after this). Clamp the tube.
3. Put on gloves
4. If a neck line, ensure the patient's head is turned away
5. Clean port with an alcohol swab for 15 seconds & allow to dry
6. Attach the syringe to the port and unclamp the tube. Withdraw 5-10 ml of blood & clamp tube.
7. Remove the syringe and discard this blood.
8. Attach a new syringe, release clamp, and withdraw the volume of blood needed for the blood sample, then clamp catheter. You can use a vacutainer at this point if you have compatible equipment
9. Attach a 10 ml 0.9% sodium chloride filled syringe. Release the clamp & flush with normal saline before re-clamping. Some trusts advise heparin flushes.
10. Give it another clean with an alcohol wipe and allow to dry.
11. Always re-attach any infusions you have stopped! Again, if in doubt ask the nurses to show you!

Further Reading

• Venepuncture video (thanks to Geeky Medics)
• Preventing blood culture contamination (thanks Rotherham NHS)

Written By Amina Aslam (FY2)

Edited By Pratyush Pradeep (FY2)

Video created by Dr Cesci Adams, Dr Michaela Gaston, Dr Siona Sabu (Clinical Teaching Fellows)