During pregnancy you are susceptible to infections which, if undetected, can harm you and your baby.

We got Dr Vinay Goel, Director and Chairman, Lifecare Medical Centre, to explain the significance of the TORCH Panel test that can help to detect past and present infections leading to miscarriage, still birth, or a child with congenital defects...

What are the pros of the TORCH Panel Test?
The TORCH test, which is sometimes called the TORCH panel, consists of tests for antibodies to four organisms that cause congenital infections transmitted from mother to foetus. TORCH test is a crucial blood test to screen for antibodies to infectious diseases. The blood tests that make up the panel are for Toxoplasmosis, Rubella, Cytomegalovirus (CMV), and Herpes simplex virus (HSV). Herpes simplex is a viral disease caused by both Herpes simplex virus type 1 (HSV-1) and type 2 (HSV-2). The name of the test is an acronym for the organisms detected by this panel: Toxoplasma gondii (toxoplasmosis), Rubella (German measles), Cytomegalovirus (CMV), and Herpes simplex virus (HSV). 

Although, the four diseases are not particularly serious for adults who are exposed and treated, these infections can be serious if they occur during pregnancy. In a pregnant woman, the infections can cross the placenta from the mother to the developing foetus, risking miscarriage, still birth, or a child with congenital defects. Thus, this test is performed to determine the mother’s history of exposure to these organisms. The test is also performed on neonatal serum when the newborn presents with symptoms consistent with a congenitally acquired infection by one of the organisms above. Rubella infection during the first 16 weeks of pregnancy poses risks for the unborn baby. It is difficult for a physician to tell if a person has rubella by their clinical appearance since other infections may look the same. Thus the TORCH test helps determine if the person has had a recent infection, a past infection, or has never been exposed.

Are there any inadequacies?
One must note that TORCH screening can be associated with both false negative and false positive results. False negative IgM tests may result from IgG antibodies to the organism binding to the antigen used in the test or from immunodeficiency syndromes that decreases the antibody response to these organisms. False positive test results can result from rheumatoid, autoimmune or heterophile antibodies in the mother’s serum. When testing neonates, the IgG antibody levels may be detected as a result of prior infection or current maternal infection, and therefore does not mean the neonate is infected. Maternal antibodies to HSV and CMV may not adequately protect the foetus. TORCH screening requires blood from the mother and if needed, the neonate. False negative or false positive results are possible. False negative is caused by bound immunoglobulin and false positive happens due to cross-reacting antibodies.

When should this test be ideally conducted?
This is used to screen pregnant women (16 weeks) and newborn infants for antibodies if either mother or baby shows symptoms. It has no link with the age, diet and lifestyle of the pregnant lady. Anytime during pregnancy on the onset of symptoms, one must take this test. The symptoms of the TORCH infections in neonates include small size for gestational age, low level of platelets in the blood, skin rash, enlarged liver and spleen, central nervous system involvement, including encephalitis, calcium deposits in the brain tissue, and seizures and jaundice. This group of defects is called the TORCH syndrome. Other organisms causing serious congenital infections such as syphilis, human immunodeficiency virus, parvovirus, and enterovirus are sometimes considered part of this group. A newborn baby with these symptoms will be given a TORCH test and may be tested for some of these other infections as well. In addition to these symptoms, each of the TORCH infections has its own characteristic symptoms in newborns.

How is the procedure conducted on the baby?
Samples from infants are usually taken by the heel stick procedure when only a small quantity of blood is needed. The baby’s foot is wrapped in a warm cloth to make the blood flow more easily. The foot is then wiped with an alcohol swab and a lancet is used to stick the baby’s heel on one side.

Is it a safe test? What are the risks involved, if any?It is a safe test. There are no risks involved for the mother, though minor temporary discomfort may occur as with any other blood test. However, one must note that there are no complications specific to TORCH testing. For the infant, complications associated with the TORCH test are those resulting from the heel stick technique/venipuncture. These risks include scarring, infection, cellulitis (inflammation of cellular tissue), and small lumpy calcium deposits. To reduce discomfort or bruising that may occur at the puncture site, one can put pressure to the puncture site until the bleeding stops. Also, applying warm packs to the puncture site relieves discomfort.

How do pets pose risk to pregnant women?
Parasite or virus spreads through body fluids of pets, especially saliva, urine and feces. Toxoplasmosis is transmitted by cat faeces. Pregnant women should avoid pet care. Patients, who are travelling abroad, for instance, to the UK and the US, must undergo these tests as the diseases on the panel, like German measles by Rubella and Herpes, are contagious.

Can this test be done on a newborn after birth or is there a wait period?
There is no waiting period required for infants. It can also be done by cerebrospinal fluid (CSF) for toxoplasmosis, rubella, urine for cytomegalovirus (CMV), herpes simplex virus (HSV) and tissue culture.

For pregnant women who test positive, what should be the way forward?
Pregnant women found to be exposed to the infection should receive treatment and a thorough explanation of potential consequences by their obstetrician is crucial. M&B

Words Poornima Nair Iyer