How Do Doctors Test Blood Plasma Levels?

Blood is made up of two main parts: a liquid and cells that are found in the liquid. Scientists refer to the liquid as plasma, which carries not only cells but also nutrients and hormones to various parts of the body. Often, doctors use a needle to withdraw blood from the body and begin a process of testing blood plasma. To perform these tests, the plasma is separated from the blood cells so that the liquid’s contents can be analyzed. For example, medical professionals may test blood plasma levels of a virus as part of the diagnosis and evaluation of a patient’s condition.

When blood is drawn from a patient, usually using a needle in his arm, the stick of the needle and little tubes of blood are usually all the patient sees. Often, however, lab scientists must test the contents of the plasma. Though most patients never see it happening, lab scientists typically treat the blood with a substance designed to stop it from forming clots. Then, they use a machine referred to as a centrifuge to isolate the plasma for testing. This process removes cells but does not remove other substances that may need testing.

An example of a test that involves blood plasma levels is one used in diabetes screening. Diabetes is a condition in which the body has a difficult time regulating blood sugar levels properly. To screen for it, doctors can take the cells out of the blood plasma and then test the plasma’s level of blood sugar, which is medically referred to as glucose. In the event that a person’s blood plasma levels of glucose are higher than expected, his doctor may determine that he has prediabetes or diabetes. Sometimes it is necessary to test levels more than once to ensure an accurate diagnosis or to monitor a patient who has already been diagnosed.

There are many others ways a doctor may use plasma testing in diagnosing or caring for patients. He may, for example, check blood plasma levels of hormones and vitamins to determine whether the patient’s body is receiving adequate amounts of these substances. A doctor can also use these tests to analyze levels of minerals called electrolytes and proteins. Additionally, doctors commonly use these tests to evaluate levels of antibodies found in the blood for infections like Human Immunodeficiency Virus (HIV) and to determine whether a person has been infected with parasites.