What is Cytomegalovirus (CMV)?
A virus which is commonly found in people of all ages. Once a person gets infected, it stays in your body for life, but a healthy person’s immune system keeps virus from causing illness. It is only in people with weakened immune system & pregnant females where it can cause complexities. While in healthy person it is known to cause mild illness with symptoms like fever, fatigue, sore throat & swollen glands. Newborns with CMV can have lung, brain, spleen, liver & growth problems.
What is CMV IgG Lab Test?
To detect CMV in an individual, CMV IgG testing (antibody testing/serology) is done. This test looks for antibodies (IgG or IgM) in blood samples which are produced by body’s immune system in response to the CMV infection. Here, immunoglobulin G (IgG) antibodies are screened which basically are produced after several weeks to the initial CMV infection. During active infection, CMV IgG levels will rise abnormally and return to normal when virus inactivates.
Why is CMV IgG Lab test done?
This test is done to diagnose active, reactivated, or past CMV infection in cases like:
- Immune-compromised patients & pregnant females with symptoms of CMV infection
- People receiving bone marrow or organ transplant
- Infants with congenital (birth) abnormalities
- What is meant by high CMV IgG levels?
High level of IgG is not as significant as rising levels. If there is a 4-fold increase in IgG levels b/w first & second sample, they show an active CMV infection (primary or reactivated).
- What is the purpose behind CMV blood test?
Cytomegalovirus infection is a condition caused by type of herpes virus. The CMV blood test is used to detect current active CMV infection, or past infection in people with risk of reactivation of CMV infection.
- What will happen if my results come CMV positive?
In people with IgG & IgM positive results, there is active infection present. Therefore, they are barred from donating till IgM results come negative.
- Can CMV be considered an autoimmune disorder?
Yes, human cytomegalovirus is linked to autoimmunity especially in people genetically predisposed.
- How can you know if CMV is active?
In some cases, symptoms occur which include tiredness/uneasiness, swollen glands, night sweats, fever, muscle & joint pain, sore throat & low appetite.
Rise in IgG levels during 1st & 2nd test mean you have an active infection (symptoms develop very rapidly). The level of IgG rising is more important than the amount of IgG found as increase in levels show that immune system is still actively fighting infection.
INTERPRETATION OF THE RESULTS
- “Positive” CMV IgG (1.1 AI or greater): indicate past or very recent infection. These individuals can spread cytomegalovirus to susceptible people via tissue & blood products.
- “Negative” CMV IgG (0.8 AI or less): indicate that there has been no prior exposure or infection of CMV & are susceptible to primary infection.
- “Equivocal” CMV IgG (0.9-1.0 AI): indicate acute infection or non-specific binding reactions. In this case another sample for testing is recommended
You get tested to diagnose primary infection from past/previous CMV infection, or if it is important to know if you ever had CMV infection which is required prior to organ transplant.