Did You Know

What Is Phlebotomy?

The goal of phlebotomy is to obtain a blood sample for analysis to be able to diagnose a medical condition.

Phlebotomy is the act of using a needle to take blood from the circulatory system. Usually, the blood is taken from a vein in the arm, by performing a puncture or an incision (cut). The goal of phlebotomy is to obtain a blood sample for analysis to be able to diagnose a medical condition. Occasionally it is performed as a part of a treatment for specific blood disorders. After the procedure, the blood is sent for testing to a laboratory. 

The Purpose Of Phlebotomy

Regular phlebotomy is performed in a large variety of cases. It makes diagnosing diseases and medical conditions much easier. However, if it is being used as a part of treatment, its medical role is significantly different. For instance, it can be used to treat polycythemia vera, which is a condition that raises the volume of red blood cells.

Patients with increased iron in their blood also use phlebotomy as a part of their therapy. Increased iron is often the result of various disorders such as sickle cell disease, hepatitis B, hepatitis C, or hemochromatosis. Another important reason phlebotomy is used for is to collect blood for blood donations. 

How Is Phlebotomy Performed?

The person performing phlebotomy is a medical technician or a nurse known as a phlebotomist. They take the blood from a vein from the back of the hand or below the elbow. Certain blood tests can, however, require that blood is taken from an artery.

The procedure itself is straightforward.

The procedure itself is very simple.
The procedure itself is very straightforward.

The nurse wipes the skin over the area where the puncture will be made. They use an antiseptic to clean it and then tie an elastic bandage around the arm. The bandage is tied around the arm to retain the blood and make the veins more visible. It is called the tourniquet. The nurse (or technician) then feels the veins to find the one that seems the most appropriate for the procedure. After locating the vein, a needle is inserted into it, and the elastic band is released. Once the necessary amount of blood is drawn, the nurse removes the needle from the arm.

There are specific tests that require a much smaller amount of blood to be drawn. In those cases, a finger stick is used. The nurse takes a tiny needle and makes a cut on the fingertip, and collects the blood in a glass tube. 

How Much Blood Is Drawn In A Phlebotomy?

The purpose of the phlebotomy determines the amount of blood that will be drawn. When donating blood, donors commonly contribute 500 mL in a single session. Far less blood is needed for laboratory analysis. Most of the time, only one small tube is drawn, which amounts to somewhere between 5 and 10 mL. Therapeutic phlebotomy, on the other hand, requires much more significant amounts of blood. Phlebotomy sessions in those cases are required more often, sometimes even once a week, and can last a few months and sometimes even several years.

Phlebotomists are trained to perform various duties, all tied to the procedure of phlebotomy. They need to know how to identify the patient, interpret the tests quickly, and know how to use the correct tubes to store blood. They also need to know which additives to use when storing blood, be skilled at preparing the patients for the process, and know the necessary precautions. In certain states, it is required for the medical staff that performs phlebotomy to be licensed or registered.

How much blood is neccessary for laboratory analysis?

Most of the time, only one small tube is drawn, which amounts to somewhere between 5 and 10 mL.

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