What Is a TORCH Screen?
A mother can pass infections to a fetus during pregnancy or delivery. Early detection and treatment of these infections is crucial for preventing complications in the newborn.
A number of prenatal tests screen for infectious diseases, including a TORCH screen. This test may also used to detect diseases in infants.
TORCH is an acronym of the five infections covered in the screening:
- other diseases, including HIV, syphilis, and measles
- rubella (German measles)
- herpes simplex
A TORCH screen is typically performed when a woman shows symptoms of any of these diseases during pregnancy. These particular diseases can cross the placenta and cause birth defects in the newborn, including:
- intellectual disability
- heart problems
- low platelet levels
The test screens for antibodies to infectious diseases. Antibodies are proteins that recognize and destroy harmful substances, such as viruses and bacteria. The presence of certain antibodies usually indicates a current or recent infection.
Antibodies can take weeks to develop, which means diagnosis can be delayed. Newer tests that are more specific and accurate than a TORCH screen have been developed. As a result, the TORCH screen is becoming less common.
Diseases Detected by a TORCH Screen
Toxoplasmosis is a disease caused when a parasite (T. gondii) enters the body through the mouth. The parasite can be found in cat litter and cat feces, as well as in undercooked meat and raw eggs. Infants infected with toxoplasmosis in the womb usually don’t show any symptoms for several years.
The “other” category can include a number of different infectious diseases, such as:
All of these diseases can be spread from the mother to the fetus during pregnancy or delivery.
Rubella, also known as German measles, is a virus that causes a rash. The side effects of this virus are minor in children. However, if rubella infects the fetus, it can cause serious birth defects such as
- heart defects
- vision problems
- delayed development
Cytomegalovirus (CMV) is in the herpes virus family. It usually doesn’t cause noticeable symptoms in adults. However, CMV can result in hearing loss, epilepsy, and intellectual disability in a developing fetus.
The herpes simplex virus is usually transmitted from the mother to the fetus in the birth canal during delivery. It’s also possible for the baby to become infected while it’s still in the womb. The infection can cause a variety of serious issues in infants, including brain damage, breathing problems, and seizures. Symptoms typically appear during the baby’s second week of life.
What Are the Risks of a TORCH Screen?
The TORCH screen is a simple, low-risk blood test. You may experience bruising, redness, and pain at the puncture site. In very rare cases, the puncture wound can become infected.
How Do I Prepare for a TORCH Screen?
A TORCH screen doesn’t require any special preparation. However, tell your doctor if you believe you’ve been infected with any of the viruses covered in a TORCH screen. You should also mention any over-the-counter or prescription medications you’re taking. Your doctor will tell you if you need to stop taking certain medicines or to avoid eating and drinking before the test.
How Is a TORCH Screen Performed?
A TORCH screen involves taking a small sample of blood. The blood is usually taken from your finger. Your doctor will clean the area and use a needle or lancet (cutting instrument) to draw blood. They’ll collect the blood in a tube, on a test strip, or in a small container.
You may feel a sharp prick or stinging sensation when the blood is drawn. There’s typically very little bleeding. If you’re bleeding after the test, they’ll apply a bandage over the puncture site.
What Do My TORCH Screen Results Mean?
The TORCH screen results show whether you currently have an infectious disease or recently had one. The results are termed either “positive” or “negative.” A positive test result means IgG or IgM antibodies were found for one or more of the infections covered in the screening. A negative test result is considered normal. This means no antibodies were detected, and there’s no current or past infection.
IgM antibodies are present when there’s a current or recent infection. If a newborn tests positive for these antibodies, a current infection is the most likely cause. If both IgG and IgM antibodies are found in a newborn, it’s probably because antibodies in the mother have been transferred to the fetus through the placenta. It doesn’t necessarily mean there’s an active infection.
There are many reasons why IgM antibodies may be present. If you test positive for IgM antibodies during pregnancy, more testing will be done to confirm an infection. The presence of IgG antibodies in a pregnant woman usually indicates a past infection. Typically, a second blood test is done two weeks later so the antibody levels can be compared. If levels increase, it means the infection was recent.
If an infection is found, your doctor will go over a treatment plan with you.