TORCH Screen Test

Sh Nilica Devi *

TORCH is an acronym for a group of infectious diseases that can cause illness in pregnant women and may cause birth-defects in their newborns. This is used to screen for the presence of any of the antibodies to these infections. The blood test can determine if the person has had a recent infection, a past infection, or has never been exposed. Confirmation of an active infection may, however, require more specific tests.

The tests that make up the TORCH panel are: Toxoplasmosis, Rubella, Cytomegalovirus, and Herpes Simplex virus.

TOXOPLASMOSIS

It is a parasitic infection that can be passed from mother to baby through the placenta during pregnancy. An infection with Toxoplasma gondii can cause eye and central nervous system infections as well as brain and muscle cysts. If acquired during the pregnancy, it may result in a miscarriage or cause birth defects, though this depends on the time during the pregnancy in which the infection was acquired by the mother.

Toxoplasmosis is acquired by ingesting the parasite when handling the excrement of infected cats, drinking unpasteurised goat’s milk, and most commonly, by eating infected contaminated meat.

RUBELLA

It is the virus that causes German measles. If contracted early in the pregnancy, the infant may develop heart disease, retarded growth, hearing loss, vision problems, or pneumonia. Problems that may develop during childhood include central nervous system disease, immune disorders, or thyroid disease.

CYTOMEGALOVIRUS (CMV)

It is another viral infection that a mother may have acquired. It may pass to the foetus during the birth process and can also infect newborns through breast milk. Infected infants may have severe problems, such as hearing loss, vision problems, mental retardation, pneumonia and seizures.

HERPES SIMPLEX VIRUS (HSV)

It is a common viral infection. The two most common infections with HSV are “cold sores” affecting the lips and genital herpes. Both of these infections can recur. HSV is most commonly acquired through oral or genital contact. Newborns who contact the virus usually do so during travel through the birth canal of a woman who has a genital infection with HSV.

The virus may spread through the newborn’s body attacking vital organs. Treatment with specific antiviral medication should begin as soon as possible in the infected newborn. Even if treated, surviving babies may have permanent damage to the central nervous system.

WHEN IS IT DONE?

The test is done when a pregnant woman is suspected of having any of the TORCH infections. These infections can be serious if they occur during pregnancy because they can cross the placenta from the mother to the developing foetus and can cause congenital defects in the newborn.

Rubella infection during the first 16 weeks of pregnancy presents major risks for the unborn baby. When a pregnant woman has a rash and other symptoms of rubella, laboratory tests are required to make the diagnosis. It is difficult to tell if a person has rubella by their clinical appearance since other infections may look the same.

Women infected with Toxoplasmosis or CMV may have flu-like symptoms that are not easily differentiated from other illnesses. Antibody testing will help the physician diagnose an infection that may be harmful to the unborn baby.

The test may be done on the newborn when the infant shows signs suggestive of these infections, such as:

o Exceptionally small size relative to the gestational age.
o Deafness.
o Mental retardation.
o Seizures.
o Heart defects.
o Cataracts.
o Enlarged liver or spleen.
o Low platelet level.
o Jaundice.

SAMPLE REQUIRED FOR THE TEST

A blood sample is required for the test. Blood can be collected from a vein in the arm or by a heelstick for infants.

PREPARATION FOR THE TEST

No special preparation is required.

WHAT DOES THE RESULT MEAN?

Results are usually given as positive or negative, indicating the presence or absence of IgG and IgM (immunoglobulins) antibodies for each of the infectious agents tested for with the panel. A “normal” result is negative (undetectable) IgM antibody in the blood for the mother or newborn.

Presence of IgM antibodies indicates either 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 is a result of maternal antibodies that have been transferred to the baby through the placenta. It does not mean that there is an infection.

During pregnancy, if a woman tests positive for IgM antibody, more testing is done to confirm an infection. There are multiple reasons IgM may be found, and more testing may be needed for confirmation of infection. The presence of IgG antibody in a pregnant woman can mean a past infection.