There Are Many Ways In Which Blood Can Be Drawn From A Vein.
July 2nd, 2009. Published under Career. 1 Comment.
Phlebotomy, also known as venesection, is performed by a nurse or a technician known as a phlebotomist. Blood is usually taken from a vein in the upper forearm (antecubetal fossa) is most often chosen for venipuncture. Arterial blood is required for blood gas measurements. Smaller quantity of blood may be obtained from the capillary bed by puncture of the skin ” a capillary puncture or skin puncture. Capillary blood is often used for point of care tests (POCT).
There are many ways in which blood can be drawn from a vein. The best method depends on the age and condition of the patient, equipment available and tests required. The veins generally used for venipuncture are those in the forearm, wrist, or ankle. Blood is most commonly obtained from the veins in the forearm since they are larger and more fuller. There are three main veins in forearm ” cephalic, median cubital, and median basilic. Usually median cubital vein in the forearm is chosen for venipuncture.
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.
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).
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.
The duties as a phlebotomist of technicians vary depending on the workplace. In a hospital, the phlebotomists 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.
Even before sample collection, patient identification is the first job of the phlebotomist. Taking blood specimens by correct puncture or incision is the duty of the phlebotomist cum hospital technician. Appropriate volume of blood should be collected as per the tests required and it is also the responsibility of the phlebotomist. Proper and accurate labeling of the samples is also another aspect of job of a hospital technician. Properly labeled samples should be promptly delivered to the testing laboratory which is ensured by the technician.
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.