Venepuncture

Handy Hints

Check that you are taking blood at the required time. Some tests are time-specific (e.g. serum digoxin level, which is assessed 6 hours after a digoxin dose, or a fasting blood for a lipid profile).
Try hanging the patient’s arm over the edge of the bed and gently tap the antecubital fossa, forearm and back of the hand veins if you can not easily find a vein. Inflate the cuff to just above DBP, and/or apply a warmed pack to the patient’s arm, to enhance venous filling.
Ultrasound is useful for finding veins and guiding venepuncture or cannulation in patients with difficult venous access
Do not use excessive suction to extract blood, as this may cause haemolysis and causes the vein to collapse and stop flow. Using a syringe to withdraw the blood allows better control of evacuation pressure, and is less likely to collapse veins. This is especially important in children or venessection from small veins.
Never, ever recap a needle.
Always invert filled blood tubes gently, especially those containing anticoagulant.
Never underfill anticoagulant tubes (citrate/blue top).
Never overfill heparinised tubes (green top), as this will cause the sample to clot.
Always remember to double-check that all samples have been labeled and that the correct patient’s details, date and time are entered prior to sending samples to the laboratory.

Complications

Needle-stick injury or blood splash to a mucous membrane.
Most likely when evacuated tubes or blood tubes are held in the hand and directly injected with blood. Do NOT do this.
Promptly wash away the blood or body fluid and encourage bleeding. Use soap, except for the eyes and mouth, and rinse well with water.
Report the incident to your supervisor as soon as possible.
Haemolysis produces unreliable laboratory results.
May be caused by incorrect venepuncture technique; pulling the tourniquet too tight or leaving it on for too long; using needles that are too small (>20G); insufficient amount of blood; incorrect filling of the blood collection tubes or too vigorous shaking of the tubes.

Ultrasound-guided Peripheral venous Access