Collection Procedures
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.
An evacuated tube and needle collection system or a sterile syringe and needle can be used for collection of blood from a vein. BD Vacutainer system tubes are widely used where BD represents the company Becton, Dickinson and company, which first marketed these tubes. Evacuated tubes can be combined to use in an infusion or butterfly set.
Vacutainer system makes use of a double ended hypodermic needle, and a holder covers the second short needle for safety. One end of the needle is inserted into the vein and the other end of the two-way needle is semi attached by a holder to the rubber stopper of vacuum tube. Blood rushes into the vacuum tube due to pressure difference between blood volume and vacuum in the tube. When the first tube gets filled with blood, it is removed and another can be filled in the same manner, thus multiple samples can be collected by single puncture. There are published standards for the use of vacutainer tubes for blood collection by the Clinical and Laboratory Standards Institute (formerly known as NCCLS).
For patients with difficult veins, a syringe and needle system is normally used. BD Vacutainer tubes are used for patients that have small delicate veins which may collapse under vacuum. For elderly patients, or patients with unreliable veins, babies, coagulation studies, obese patients with difficult veins, intravenous therapy patients with scarred veins, and for veins on wrist, back of hand, ankle, foot, or scalp, an infusion set (Butterfly) is used.
Phlebotomist can have various duties depending on the place of work. Providing assistance to doctors is the primary duty of a phlebotomist in a hospital. Nurses and phlebotomists work in coordination in hospitals. Blood or tissue sample collection is one of the major duties of a hospital technician working as a phlebotomist.
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.
Phlebotomists can complete either on job training, cross train from another health care profession, or a formal program from phlebotomy training schools to attain these competencies. Phlebotomy certification from professional associations leads to skill refinement and continuous education for practicing phlebotomists.
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