Torch PCR

The TORCH test is a panel of blood tests used to screen for infections that can cause serious complications during pregnancy and affect the fetus or newborn.

TORCH stands for:

●     T – Toxoplasmosis

●     O – Other infections (e.g., Syphilis, Hepatitis B, Varicella-Zoster, Parvovirus B19, HIV, and Listeria)

●     R – Rubella (German Measles)

●     C – Cytomegalovirus (CMV)

●     H – Herpes Simplex Virus (HSV)

These infections can be transmitted from mother to baby during pregnancy, childbirth, or breastfeeding, potentially causing severe congenital infections, birth defects, pregnancy complications, or long-term health problems in the newborn.

Components of the TORCH Panel

●     Toxoplasmosis (T): Caused by Toxoplasma gondii, usually acquired through undercooked meat, contaminated food/water, or cat feces. In pregnancy, it can lead to miscarriage, stillbirth, hydrocephalus, eye damage, and intellectual disability in the fetus.

●     Other Infections (O): Includes Syphilis, Hepatitis B, Varicella-Zoster (Chickenpox), Parvovirus B19, HIV, and Listeria, all of which can cause serious fetal or neonatal complications such as congenital infections, birth defects, anemia, chronic disease, or stillbirth.

●     Rubella (R): Infection during pregnancy, especially in the first trimester, can cause Congenital Rubella Syndrome (CRS), leading to heart defects, cataracts, hearing loss, intellectual disability, and microcephaly.

●     Cytomegalovirus (CMV) (C): The most common congenital infection worldwide and a major cause of hearing loss, vision problems, developmental delay, microcephaly, and stillbirth.

●     Herpes Simplex Virus (HSV) (H): HSV-1 and HSV-2 can be transmitted to the newborn during pregnancy or delivery, causing skin, eye, neurological, or life-threatening systemic infections.

Antibody Testing

The TORCH panel measures:

●     IgM antibodies – Indicate a recent or active infection.

●     IgG antibodies – Indicate past infection, prior vaccination, or immunity.

Interpreting IgM and IgG together helps determine whether an infection is new, past, or reactivated, which is critical during pregnancy.

Who should get this test done?

This test is recommended for:

●     Pregnant women, especially in the first trimester, to detect infections that may harm the fetus.

●     Pregnant women with fever, rash, flu-like symptoms, or lymphadenopathy suggestive of TORCH infection.

●     Women with recurrent miscarriages, stillbirths, or intrauterine fetal death.

●     Women with abnormal prenatal ultrasound findings (e.g., growth restriction, brain abnormalities, hydrops fetalis, calcifications).

●     Newborns with congenital abnormalities, jaundice, seizures, skin lesions, or feeding difficulties.

Why consider this test?

TORCH infections can severely affect the fetus or newborn while causing mild or no symptoms in the mother. Testing helps:

●     Detect active or recent maternal infections during pregnancy.

●     Diagnose congenital infections in newborns with birth defects or unexplained illness.

●     Determine pre-pregnancy immunity to vaccine-preventable infections such as Rubella and Varicella.

●     Evaluate newborns with jaundice, rashes, seizures, hearing or eye abnormalities, or hepatosplenomegaly.

●     Monitor known TORCH infections and assess disease progression and fetal risk during pregnancy.

More Information

The TORCH panel detects IgM and IgG antibodies, reflecting the body’s immune response rather than directly detecting the pathogen.

●     Positive IgM: Suggests recent or active infection, though it may persist for months or produce false-positive results.

●     Positive IgG: Indicates past infection or vaccination and usually implies immunity.

●     IgG Avidity Testing: Helps determine timing of infection—high avidity suggests an older infection, while low avidity indicates a recent primary infection with higher fetal risk.

●     PCR testing (for CMV, HSV, etc.) may be used for direct pathogen detection when serology is inconclusive.

●     A positive TORCH result does not necessarily mean fetal infection; transmission risk depends on the pathogen, gestational age, maternal immunity, and timely treatment.

Other names:

●     TORCH Panel

●     TORCH Screen

●     TORCH Titre Test

●     Congenital Infection Screen

●     Perinatal Infection Panel

●     Maternal Infection Screen

●     Antenatal TORCH Profile

●     ToRCH IgG / IgM Panel

●     Congenital TORCH Antibody Test

●     Prenatal Infectious Disease Panel