Cytomegalovirus (CMV) Tests
Reviewed
Also called: CMV IgG and IgM, cytomegalovirus antibody
Cytomegalovirus (CMV) tests check for signs of CMV in your blood, sputum, or other body fluids. CMV is a virus in the herpes family.
Specimen: Blood, cerebrospinal fluid, sputum, tissue, amniotic fluid, infant saliva, infant urine
Why this test may be ordered
- To diagnose a current, reactivated, or past CMV infection in people at risk for health complications.
- If you have a weakened immune system or are pregnant and have symptoms such as swollen lymph nodes, sore throat, fever, fatigue, weakness, muscle aches, or headache.
- For newborns with symptoms such as jaundice, low birth weight, small head, hearing and/or vision problems, seizures, or rash.
Preparation and collection
You don't need any special preparations for a blood or sputum test. There are also no preparations needed for an infant saliva or urine test. You may need to empty your bladder before a spinal tap. You may be asked to fast (not eat or drink) for several hours before a biopsy. For an amniocentesis, you may be asked to not urinate (pee) before the test to make sure you have a full bladder. Your provider or your child's provider will let you know if you need to make any other preparations.
There are several types of CMV tests. For a blood test, a health care professional will take a blood sample from a vein in your arm, using a small needle. This is the most common way to test adults for CMV.
There is very little risk to having a blood test. You may have slight pain or bruising at the spot where the needle was put in, but most symptoms go away quickly. There is very little risk to having a spinal tap. You may also get a headache. The headache may last for several hours or up to a week or more, but your provider may suggest treatment to relieve the pain. If you had a biopsy, you may have a little bruising, bleeding, or soreness at the biopsy site. Afterward, you may have mild discomfort or vaginal bleeding, or a small amount of amniotic fluid may leak from your vagina. Your provider will let you know if there are any symptoms that you should tell them about. These may include ongoing vaginal bleeding, amniotic fluid leakage, severe cramping, or a fever.
Understanding results
The test result can show whether you have ever had a CMV infection. If your provider used antibody testing, they may also be able to see if your infection is active or inactive.
- Positive (IgM antibodies found): Your immune system usually only makes IgM when you first get an infection. So, if you have IgM in your sample, it may mean you have an active CMV infection. Limitation: The test result can show whether you have ever had a CMV infection. Next step: If you have symptoms and/or risk factors, such as an immune system disorder, your provider may do additional tests to help make a diagnosis and create a treatment plan.
- Negative: If the test comes back negative, it does not necessarily mean there is no CMV present in your body. Limitation: It may only mean that there are very low levels of the virus. Next step: If you have symptoms and/or risk factors, such as an immune system disorder, your provider may do additional tests to help make a diagnosis and create a treatment plan.
- High virus levels on a PCR test: High levels with symptoms of CMV may mean you have a severe infection. Limitation: A PCR test can show how much of the CMV virus is present. Next step: If you have questions about your results, talk to your provider or your child's provider.
- A negative result does not necessarily mean there is no CMV in your body; it may only mean the virus is at very low levels.
- If you have symptoms and/or risk factors such as an immune system disorder, your provider may do additional tests to help make a diagnosis and create a treatment plan.
What to do next
If you are pregnant and your amniocentesis shows your fetus has CMV, your child's provider may test and treat your baby soon after birth to help prevent complications. If you have questions about your results, talk to your provider or your child's provider.
- What do my results mean for my health or my baby's health?
- Do I need any additional tests to confirm or clarify the result?
- What follow-up care or monitoring is recommended based on my results?
Evidence source
Source: U.S. National Library of Medicine (MedlinePlus). Practices and reference ranges may differ in your country.
U.S. National Library of Medicine: Cytomegalovirus (CMV) Tests