TORCH PANEL (IgM)

Overview

Perinatal infections account for 2-3% of all congenital anomalies. TORCH which includes Toxoplasma, Rubella, Cytomegalovirus & Herpes Simplex virus, are some of the most common infections associated with Congenital anomalies. Most of the TORCH infections cause mild maternal morbidity, but have serious fetal consequences. Reliable recognition of acute infection is highly important in pregnant women. IgM positive result alone does not accurately predict the risk of fetal infection; a positive IgM test should therefore be considered only as a starting point and a more thorough diagnostic evaluation is necessary to determine whether there is a risk of fetal infection. Toxoplasmosis is acquired by humans through ingestion of food or water contaminated with cat feces or through eating undercooked meat containing viable oocysts. Vertical transmission of the parasite through the placenta can also occur, leading to Congenital toxoplasmosis. Rubella is a viral exanthematous infectious disease caused by Rubella virus. The disease is usually accompanied by lymphadenopathy. Infection confers lifelong immunity. Rubella-specific IgM is found in virtually all infected patients by 3 weeks post development of a rash. Rubella-specific IgM is also found in 80% of post-vaccination patients by three weeks. Primary CMV infection may result in establishment of persistent or latent infection. Infections can be acquired through direct contact with individuals shedding the virus. CMV can be transmitted vertically and horizontally, and infection can be classified as being acquired before birth (prenatal), at the time of birth (perinatal) or later in life (postnatal). Infections are usually mild and asymptomatic but may pose a significant medical risk in pregnant women, newborns and immunocompromised individuals. Asymptomatic HSV infections may occur in healthy individuals and during pregnancy. Once infection occurs, HSV persists in a latent state in sensory ganglia from where it may re-emerge to cause periodic recurrence of infection induced by many stimuli, which may or may not result in clinical lesions. In immunocompromised patients the disease is more severe and they are more likely to have frequent HSV recurrences. Acute infection of TORCH is suggested by the presence of IgM antibody or seroconversion or rising antibody titres between acute and convalescent serum & low IgG avidity except in HSV infections.