This test detects the presence of antibodies in the blood to cytomegalovirus, abbreviated as CMV. The body produces antibodies, special proteins designed to defend against bacteria, viruses, and other harmful foreign particles.
The CMV test is performed when a healthcare professional suspects a CMV infection may be present. CMV usually only causes serious infections in a person who has a weakened immune system for one of these reasons: taking medicines to suppress the immune system, such as after an organ transplantcancer or AIDS
In order to test for CMV antibodies, a blood sample is needed. The blood is usually drawn from a vein in the forearm. First, the skin over the vein is cleaned with an antiseptic. Next, a strong rubber tube, called a tourniquet, is wrapped around the upper arm. This enlarges the veins in the lower arm by restricting blood flow.
A thin needle is inserted into a vein, and the tourniquet is removed. Blood flows from the vein through the needle and is collected in a syringe or vial. After the needle is withdrawn, the puncture site is covered for a short time to prevent bleeding. The sample is sent to the lab to be analyzed.
No preparation is required for this test.
In people who have not been infected with CMV, there are no antibodies to CMV in the blood. This is considered a negative test. If a person has antibodies against CMV, the test is positive. This means that a person has been infected with CMV in the past.
Once a person has had a CMV infection, the virus generally stays in the body for life. When the immune system becomes weak, the infection can sometimes return. If the infection returns, strong antiviral medications may be needed to treat it.