Hepatitis C Antibody Screen with Reflex to HCV RNA by PCR, Serum
Method Description Describes how the test is performed and provides a method-specific reference
The VITROS anti-hepatitis C virus (HCV) assay is performed using the VITROS Anti-HCV Reagent Pack and VITROS Immunodiagnostic Products Anti-HCV Calibrator on the VITROS 3600 Immunodiagnostic System (Ortho-Clinical Diagnostics, Inc., Raritan, NJ). An immunometric technique is used, involving a 2-stage reaction. In the first stage, HCV antibody present in the sample binds to HCV recombinant antigens coated on the reaction wells, and unbound sample is removed by washing. In the second stage, horseradish peroxidase (HRP)-labeled antibody conjugate (mouse monoclonal antihuman IgG) binds to human IgG captured on the well in the first stage. Unbound conjugate is removed by washing. A reagent containing luminogenic substrates (a luminal derivative and a peracid salt) and an electron transfer agent is added to the wells. The HRP in the bound conjugate catalyzes the oxidation of the luminal derivative, producing light. The electron transfer agent increases the level and duration of the light produced. The emitted light signals are detected and measured by the VITROS 3600 Immunodiagnostic System. The amount of HRP conjugate bound is directly proportional to the level of anti-HCV antibodies present in a given sample.(Ismail N, Fish GE, Smith MN: Laboratory evaluation of a fully automated chemiluminescence immunoassay for rapid detection of HBsAg, antibodies to HBsAg, and antibodies to hepatitis C virus. J Clin Microbiol 2004;42:610-617)
The COBAS AmpliPrep/COBAS TaqMan HCV Test is a Food and Drug Administration (FDA)-approved in vitro assay based on an automated method (AmpliPrep) for nucleic acid extraction and purification and a homogeneous (real-time) PCR method (TaqMan) for amplifying the HCV-specific 5' UTR sequence (241 bp size) and generating a signal by cleaving a target-specific TaqMan probe during amplification. The probe contains a reporter fluorophore and a quencher dye that absorbs light emitted by the reporter. Cleavage of the probe physically separates the quencher from the reporter, enabling light emitted by the latter to be detected by a photomultiplier tube. Because amplification and detection are performed simultaneously, amplification products are measured during the exponential phase of DNA amplification regardless of the initial target concentration.(Package insert: COBAS AmpliPrep/COBAS TaqMan HCV Test; Roche Molecular Systems, Inc., Branchburg, NJ)
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.
HCV antibody screen: Monday through Saturday; 8 a.m.-12:30 a.m., Sunday; 8 a.m.-4:30 p.m.
HCV RNA detection and quantification by RT-PCR: Monday through Saturday; 7 a.m.-4 p.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.
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