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One-StepTORCH IgG/IgM Rapid Test
The One Step TORCH IgM Test is a panel of rapid qualitative lateral flow test designed for the quantitive detection of IgM antibodies to Toxoplasma gondii (TOXO), Cytomegalovirus (CMV), Rubella, Herpes Simplex Virus (HSV) in human serum/plasma samples.
Rubella is a herpes virus. Generally, rubella is considered a mild adolescence disease. However, a maternal infection could be transmitted through the placenta to the fetus, causing congenital rubella. Congenital rubella may result in chronic cardiac disease, growth retardation, hepatosplenomegaly, malformations and other severe anomalies. Children born asymptomatic may develop these abnormalities later in life. To reduce the risk of such severe complications, accurate serological methods must be performed to determine the serologic status of childbearing aged women. The presence of rubella specific IgG in the bloodstream attests immunity to rubella. A woman tested to be non-immune can be educated on the availability of vaccination. An increase in rubella IgG denotes an acute infection and differentiates rubella from other exanthematous diseases. Expecting women with current rubella infection should be counseled on the consequences of congenital infection.
Cytomegalovirus is a herpes virus and a leading biological factor causing congenital abnormalities and complications among those who receive massive blood transfusions and immunosuppressive therapy. About half of the number of pregnant women who contract a primary infection, spread the disease to their fetus. When acquired in-utero, the infection may cause mental retardation, blindness, and/or deafness. Serological tests for detecting the presence of antibody to CMV can provide valuable information regarding the history of previous infection, diagnosis or active or recent infection , as well as in screening blood for transfusions in newborns and immuno-compromised recipients.
T. gondii is an obligate intracellular protozoan parasite with a worldwide distribution (5, 6). Serological data indicate that approximately 30% of the population of most industrialized nations is chronically infected with the organism (7). When a seronegative woman becomes infected with T. gondii during pregnancy, the organism is often transmitted across the placenta to the fetus (5, 8). The severity of the infection in the fetus varies with the trimester during which the infection was acquired. Infection during pregnancy may lead to spontaneous abortion, stillbirth or overt diseases in the neonate. Approximately 75% of congenitally infected newborns are symptomatic. However, nearly all children born with subclinical toxoplasmosis will develop adverse ocular or neurologic sequelae later in life (8, 11). Approximately 80-85% develops chorioretinitis and some may also experience blindness or mental retardation.
A variety of serologic tests for antibodies to T. gondii have been used as an aid in diagnosis of acute infection and to assess previous exposure to the organism. The more widely used tests include the Sabin-Feldman dye test, direct agglutination, indirect hemagglutination, latex agglutination, indirect immunofluorescence, and ELISA (9, 10).
HSV(Herpes Simplex Virus)
HSV-1 is usually associated with infection in oropharyngeal area and eyes, while HSV-2 causes mostly genital and neonatal infections (5, 6), however, the tissue specificity is not absolute (7). HSV-2 can be isolated occasionally from the oropharynx and 5-10% of primary genital infections may be caused by HSV-1. Infants infected with HSV appear normal at birth, but almost invariably develop symptoms during the newborn period (5, 8, 9). Neonatal HSV infection may remain localized or become disseminated. Localized infection may involve one or a combination of sites. These are skin, eyes, mouth or the central nervous system. Disseminated infection is manifested by pneumonitis, hepatitis, disseminated intravascular coagulopathy and encephalitis. Of the infants with neonatal HSV, about one half of those surviving will develop severe neurological or ocular sequelae. A number of serological procedures have been developed to detect antibodies to HSV. These include complement fixation, indirect immunofluorescent antibody, plaque neutralization, and ELISA (6, 8, 10). Antibody of the IgM class is produced during the first 2-3 weeks of infection with HSV and exists only transiently in most patients. Serologic procedures, which measure the presence of IgM antibodies, help discriminate between primary and recurrent infections, since IgM antibodies is rarely found in recurrent infections. High affinity IgG antibodies to HSV, if present in a sample, may interfere with the detection of IgM specific antibody (9). High affinity IgG antibody may preferentially bind to HSV-1 antigen leading to false negative IgM results. Also, rheumatoid factor, if present, along with antigen specific IgG, may bind to IgG causing false positive IgM results. Both problems can be eliminated by deactivating IgG in the sample before testing for IgM.
The ToRCH Rapid Test Device (Serum/Plasma) has been designed to detect IgM antibodies to TOXO, CMV, Rubella and HSV through visual interpretation of color development in the internal strip. The membrane was immobilized with antigens of TOXO, CMV, Rubella and HSV on the test region. During the test, the specimen is allowed to react with colored recombinant mouse anti-human IgM latex conjugates, which were precoated on the sample pad of the test. The mixture then moves on the membrane by a capillary action, and interact with reagents on the membrane. If there were enough TOXO, CMV, Rubella and HSV antibodies in specimens, a colored band will from at the test region of the membrane. Presence of this colored band indicates a positive result, while its absence indicates a negative result. Appearance of a colored band at the control region serves as a procedural control. This indicates that proper volume of specimen has been added and membrane wicking has occurred.
|Individually packed test devices||Each device contains a strip of TOXO, CMV, Rubella and HSV with colored conjugates and reactive reagents pre-spreaded at t he corresponding regions.|
|Disposable pipettes||For adding specimens use.|
|Buffer||Phosphate buffered saline and preservative.|
For operation instruction.
MATERIALS REQUIRED BUT NOT PROVIDED
|Specimen collection container||For specimens collection use.|
|Timer||For timing use.|
For preparation of clear specimens
Contact Person: Ms. Anna Lee