ToRCH Profile IgM, Serum
Method Description Describes how the test is performed and provides a method-specific reference
The VIDAS TOXO IgM system (bioMerieux Inc, Durham, NC) is an automated serologic test for use on the VIDAS analyzer that employs the enzyme-linked fluorescence assay (ELFA) technique. The assay uses a 2-step EIA sandwich method. A pipette tip-like device, the solid phase receptacle (SPR) is coated with goat anti-IgM antibodies and serves as the solid phase as well as the pipettor for the assay. The sample is diluted and cycled in and out of the SPR. Subsequently Toxoplasma gondii antigen, followed by mouse anti- Toxoplasma gondii antigen-conjugated antibodies are cycled through the SPR. A fluorescent substrate, 4-methylumbelliferyl phosphate, is added to the SPR, which catalyzes the conversion of the conjugated substrate to a fluorescent product. The intensity of the fluorescence is measured by the optical scanner of the instrument.(Package insert: VIDAS TOXO IgM, bioMerieux Inc, Durham, NC)
The BioPlex 2200 CMV IgM assay uses multiplex flow immunoassay technology. Briefly, CMV antigen-coated fluorescent beads are mixed with an aliquot of patient sample and sample diluent and incubated at 37 degrees C. During this time, IgM anti-CMV antibodies in the specimen will bind to the CMV antigen on the beads. After a wash cycle, a fluorescently labeled antihuman-IgM antibody conjugate is added to the mixture and incubated at 37 degrees C. Following a wash step to remove unbound conjugate, the bead mixture is passed through a detector that identifies the bead based on dye fluorescence and determines the amount of antibody captured by the antigen based on fluorescence of the antihuman IgG conjugate. Raw data is calculated in relative fluorescence intensity and is converted to an antibody index (AI) for interpretation.
Three additional dyed beads, an internal standard bead, a serum verification bead, and a reagent black bead are present in each reaction mixture to verify detector response, the addition of serum to the reaction vessel, and the absence of significant nonspecific binding in serum, respectively.(Package insert: BioPlex 2200 System, ToRC IgG, Bio-Rad Laboratories, Clinical Diagnostics Group, Hercules, CA)
Herpes Simplex Virus (HSV):
The indirect immunofluorescence test is used for the detection of IgM-class antibodies to HSV. After removal of IgG by specific immunoglobulin antibody, the serum is reacted with HSV-infected substrate cells on a slide. Specific fluorescence indicating the presence of IgM antibodies to HSV in the specimen can be detected by an immunofluorescence microscope.(Arvin AM, Prober CG: Herpes Simplex Viruses. In Manual of Clinical Microbiology. Seventh edition. Edited by PR Murray, EJ Baron, MA Pfaller, et al. Washington, DC, ASM Press, 1999, pp 878-887)
Day(s) and Time(s) Test Performed Outlines the days and times the test is performed. This field reflects the day and time the sample must be in the testing laboratory to begin the testing process and includes any specimen preparation and processing time required before the test is performed. Some tests are listed as continuously performed, which means assays are performed several times during the day.
Monday through Saturday; 9 a.m.
Analytic Time Defines the amount of time it takes the laboratory to setup and perform the test. This is defined in number of days. The shortest interval of time expressed is "same day/1 day," which means the results may be available the same day that the sample is received in the testing laboratory. One day means results are available 1 day after the sample is received in the laboratory.
Same day/1 day
Maximum Laboratory Time Defines the maximum time from specimen receipt at Mayo Medical Laboratories until the release of the test result
Specimen Retention Time Outlines the length of time after testing that a specimen is kept in the laboratory before it is discarded
Performing Laboratory Location The location of the laboratory that performs the test