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Cytomegalovirus (CMV) Blood Test

Last updated Oct. 11, 2015

Approved by: Krish Tangella MD, MBA, FCAP

The Cytomegalovirus (CMV) Blood Test detects the presence of CMV in blood.


What are the other Names for this Test? (Equivalent Terms)

  • CMV Blood Test
  • CMV by PCR Blood Test
  • Cytomegalovirus IgG and IgM Antibodies Blood Test

What is Cytomegalovirus Blood Test? (Background Information)

  • Cytomegalovirus (CMV) is a type of herpes virus that may cause a flu-like disease. The virus is very common and occurs latently in most of the humans (about 60-80% of them), but remains inactive if the host immunity is strong and healthy
  • CMV can transfer from a mother to her unborn child. More often, CMV spreads through contact with infected individuals via body fluids or surfaces. After infection, CMV replicates in cells, damaging them and activating the immune system. This causes the flu-like symptoms
  • Occasionally, CMV may infect the intestines, causing bloody diarrhea. It may also infect the lungs, causing pneumonia; the brain, causing encephalitis; and the eyes, causing impaired vision and even blindness
  • CMV causes serious symptoms only in susceptible individuals. These include individuals with lowered or underdeveloped immune systems, such as the elderly, the young, people undergoing chemotherapy, and those with HIV infection. Disinfection and hand washing may minimize the risk
  • Individuals with healthy immune systems can typically control CMV infection by themselves. However, in cases of serious illness, drugs called viral polymerase inhibitors may be used
  • CMV goes into hibernation after it has completed the “active” part of its infection, which is characterized by symptoms. The virus infiltrates the DNA of cells and then lies dormant. It can emerge during times of stress or immune system suppression

The Cytomegalovirus (CMV) Blood Test detects the presence of CMV in blood. It does this in two different ways:

  • Detection of specific antibodies created by the immune system upon exposure to CMV: The presence of CMV-specific IgM antibodies indicates a recent or current exposure; CMV-specific IgG antibodies indicate a past exposure
  • Detection of genetic material belonging to CMV: A technique called PCR (polymerase chain reaction) is used to detect traces of specific DNA that CMV is known to possess, but which is absent in humans

What are the Clinical Indications for performing the Cytomegalovirus Blood Test?

Following are the clinical indications for performing the Cytomegalovirus Blood Test:

  • Swollen lymph nodes
  • Fever
  • Bloody diarrhea
  • Muscle aches
  • Nausea
  • Vomiting
  • Headache
  • Altered mental status
  • Visual problems
  • Enlarged liver or spleen

How is the Specimen Collected for Cytomegalovirus Blood Test?

Following is the specimen collection process for Cytomegalovirus (CMV) Blood Test:

Sample required: Blood

Process of obtaining blood sample in adults:

  • A band is wrapped around the arm, 3-4 inches above the collection site (superficial vein that lies within the elbow pit)
  • The site is cleaned with 70% alcohol in an outward spiral, away from the zone of needle insertion
  • The needle cap is removed and is held in line with the vein, pulling the skin tight
  • With a small and quick thrust, the vein is penetrated using the needle
  • The required amount of blood sample is collected, by pulling the plunger of the syringe out slowly
  • The wrap band is removed, gauze is placed on the collection site, and the needle is removed
  • The blood is immediately transferred into the blood container, which has the appropriate preservative/clot activator/anti-coagulant
  • The syringe and the needle are disposed into the appropriate “sharp container” for safe and hygienic disposal

Preparation required: No special preparation is needed prior to the test.

What is the Significance of the Cytomegalovirus Blood Test Result?

A positive Cytomegalovirus (CMV) Blood Test may indicate infection by CMV.

The laboratory test results are NOT to be interpreted as results of a "stand-alone" test. The test results have to be interpreted after correlating with suitable clinical findings and additional supplemental tests/information. Your healthcare providers will explain the meaning of your tests results, based on the overall clinical scenario.

Additional and Relevant Useful Information:

  • CMV is a very common virus that is present in 50-85% of US adults under 40 years of age

Certain medications that you may be currently taking may influence the outcome of the test. Hence, it is important to inform your healthcare provider, the complete list of medications (including any herbal supplements) you are currently taking. This will help the healthcare provider interpret your test results more accurately and avoid unnecessary chances of a misdiagnosis.

  • The cytomegalovirus test is included in the TORCH panel of tests. The TORCH panel is a series of tests for common infections that can be transmitted from a mother to her unborn child. The others on the panel include toxoplasmosis, rubella, and herpes simplex type 2

The following article link will help you understand TORCH Panel Blood Test:

https://www.dovemed.com/common-procedures/procedures-laboratory/torch-panel-blood-test/

Please visit our Laboratory Procedures Center for more physician-approved health information:

http://www.dovemed.com/common-procedures/procedures-laboratory/

References and Information Sources used for the Article:


Reviewed and Approved by a member of the DoveMed Editorial Board
First uploaded: May 15, 2015
Last updated: Oct. 11, 2015