Hepatitis Bs Antigen (HBsAg) for Cadaveric or Hemolyzed Specimens, Serum
Method Description Describes how the test is performed and provides a method-specific reference
Specimens are first screened by the Genetic Systems HBsAg 3.0 EIA. All reactive results are confirmed by the Genetic Systems HBsAg Confirmatory Assay 3.0 (HBsAg Neutralization) at an additional charge.
Wells of a microwell strip plate that are coated with mouse monoclonal antibody to hepatitis B surface antigen (HBsAg) are incubated with patient serum appropriate controls and mouse monoclonal anti-hepatitis B surface (anti-HBs) peroxidase conjugate. HBsAg, if present, is bound to the solid-phase antibody and simultaneously bound by the anti-HBs conjugate. After aspiration and washing, working chromogen solution is added to the wells. After incubation, a blue or blue-green color develops in proportion to the amount of HBsAg bound to the bead.
The enzyme reaction is stopped by the addition of acid resulting in a color change to yellow. The absorbance values of controls and specimens are determined using a spectrophotometer with wavelength set at 450 nm. Specimens giving absorbance values equal to or greater than the absorbance value of the negative control mean plus a factor are considered initially reactive for HBsAg. Those giving absorbance values less than the negative control mean plus a factor are considered negative. (Package insert: Genetic Systems HBsAg 3.0 EIA. Bio-Rad Laboratories, Redman, WA)
The Genetic Systems HBsAg Confirmatory Assay 3.0 uses the principle of specific antibody neutralization to confirm the presence of HBsAg. The confirmatory reagent (human antibody to HBsAg) is incubated with the specimen in solution. If HBsAg is present in the specimen, it will be bound by the confirmatory reagent. The treated specimen is reassayed using the Genetic Systems HBsAg 3.0 EIA kit. The neutralized HBsAg is subsequently blocked from binding to the antibody-coated wells. This results in a reduction of signal when compared to the nonneutralized specimen in which negative control is used in place of confirmatory reagent. By definition, a specimen is confirmed as positive if the reduction in signal of the neutralized specimen is at least 50% and the nonneutralized control generates a signal greater than or equal to the assay cutoff. (Package insert: Genetic Systems HBsAg Confirmatory Assay 3.0. Bio-Rad Laboratories, Redman, WA)
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, Wednesday, Friday; Varies
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.
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