Venepuncture or phlebotomy is performed by phlebotomy technician or an allied health professional like a nurse. The most common site used is in the upper forearm called antecubetal fossa. Blood gas measurements require oxygenated arterial blood. Some tests require very small quantity of blood which is collected by skin puncture called as capillary bed blood collection. Points of care tests (POCT) make use of capillary blood.

Venous blood can be collected in many ways. Venipuncture methods can vary depending on the test requirements, age, and physical condition of the patients. The sites to use are those in forearm, wrist, or ankle but the common is forearm veins. This is because forearm veins are generally more fuller and larger than other veins. Three main veins in the forearm are cephalic, median cubital, and median basilic.

Blood may be obtained directly from a vein using an evacuated tube and needle collection system or by using a sterile syringe and needle. Vacuum tubes were first marketed by BD (Becton, Dickinson and company, BD Vacutainer system). An infusion or butterfly set can be used in combination with the evacuated tube method.

A double ended hypodermic needle is used to puncture the vein in the evacuated tube method, where the shorter end of needle is covered by the holder for phlebotomist safety. One end of the needle is inserted into the vein and the other end is partially attached to a rubber stopper of a special vacuum tube. The rubber cap of the holder is pierced by the second needle when the vacutainer test tube is pushed down into the holder, and this creates a pressure difference in the blood volume and the blood is forced through the needle into the tube by the vacuum present in the tube. Next sample is collected in the same way after removing the tube and inserting another tube. The presence of suction in the tube makes it important to remove the tube before withdrawing the needle from the vein. Evacuated tubes are used for blood specimen collection as per standards set by The Clinical and Laboratory Standards Institute (formerly NCCLS).

A syringe and needle system is often used to collect blood from patient with difficult veins. This is useful for patients that have smaller veins that collapse under the vacuum of BD Vacutainer tubes. An infusion set (Butterfly) is often used for coagulation studies, for babies, and small children with small veins, for obese patients with hard to find veins, for patients receiving intravenous therapy with scarred veins, and for veins other than those in antecubital fossa (wrist, back of hand, ankle, foot, or scalp).

The duties as a phlebotomist of technicians vary depending on the workplace. In a hospital, the phlebotomist’s primary duty is to assist doctors. The technician also coordinates with nurses. One of the duties as a phlebotomist of a hospital technician is to take blood or tissue samples from patients.

Proper patient identification is an important process before sample collection for a phlebotomist. Correct puncture or incision of patient’s skin to take specimens is the responsibility of a phlebotomist. Enough volume of blood or tissue should be taken for the specific test and this is the duty of the phlebotomist. Phlebotomist’s role also is to correctly label the sample and transport the labeled samples to the testing lab on time.

To achieve these competencies, training from a certified program, or on job training, or cross training from other healthcare profession can be completed by the phlebotomists. Professional association certification leads to fine tuned skills for already employed technicians / phlebotomists and learning basic skills for new graduates.

Written by Phlebotomy Training specialist Dr Shahbaz A. Cheema, Course Director for Maxis Healthcare who run NHS Accredited Phlebotomy Training courses for medical and non medical practitioners. Learn the 3 Steps To Become a Phlebotomist