Cytomegalovirus (CMV) Antibody, IgG, Blood

Why This Test Might Be Ordered

Your healthcare provider may order this test if you have symptoms of CMV infection, such as fatigue, fever, or swollen lymph nodes, especially if you have a weakened immune system. It may also be used to check for immunity before certain medical procedures, like organ transplants, or to monitor immune function in people with HIV/AIDS or other immune disorders.

What to Expect Before the Test

No special preparation is needed for this blood test. You may have a small needle inserted into your arm to draw a blood sample. If you’re on blood thinners or have a history of bleeding issues, let your provider know beforehand.

What the Test Results Mean

A positive result means you have IgG antibodies, suggesting you’ve likely had CMV in the past and may have some immunity. A negative result means you don’t currently have detectable IgG antibodies, which could mean you’ve never been exposed or the test was taken too soon after exposure. Results alone don’t confirm active infection; other tests may be needed.

Common Reasons for Testing

This test is often used in conjunction with other tests to assess immune status, evaluate symptoms of infection, or guide treatment decisions, particularly in people with compromised immune systems.