Objective: The LIAISON® HSV-1 IgG and LIAISON® HSV-2 IgG Assays are two new fully automated type specific immunoassays based on chemiluminescence technology. Our goal was to compare the results obtained from the analysis of serum samples using the LIAISON HSV-1 IgG and LIAISON HSV-2 IgG Assays to results from the Focus Diagnostics HerpeSelect® 1 and 2 Immunoblot IgG Kit, a manual immunoassay.
Methods: Human serum samples were analyzed by both the automated and manual methods. The automated LIAISON HSV-1 IgG and LIAISON HSV-2 IgG Assays are qualitative chemiluminescent immunoassays for the detection of specific IgG antibodies to Herpes Simplex Virus Type 1 or Herpes Simplex Virus Type 2, respectively. Paramagnetic particles are coated with recombinant gG1 specific to HSV-1 or recombinant gG2 specific to HSV-2. Human antibodies present in calibrators, controls, or samples bind to coated particles during the first incubation. Unbound material is removed with a wash cycle. During the second incubation, an isoluminol tracer linked to anti-human IgG mouse monoclonal antibody attaches to human antibodies bound on the solid phase. After another wash, the addition of starter reagents induces a flash chemiluminescent reaction, and a photomultiplier measures the light signal. The light signal is proportional to the amount of human antibody bound to the particles. Time to first result is 35 minutes, with throughput of 90 tests per hour. Manufacturer’s directions were followed for performing the Focus Diagnostics HerpeSelect 1 and 2 Immunoblot IgG Kit.
Results: A population containing prospective (those with signs and symptoms of HSV), low-risk (non-sexually active individuals), and pregnancy (prenatal) samples (n=583) was assayed by the LIAISON HSV-1 IgG Assay, the LIAISON HSV-2 IgG Assay, and the HerpeSelect 1 and 2 Immunoblot IgG Kit. Overall agreement of 95.9% (559/583) was obtained between the two HSV-1 assay methods, with 90.2% (174/193) negative agreement and 99.7% (384/385) positive agreement. Furthermore, in another analysis, 90% of 21 samples that were positive by LIAISON and negative by the Immunoblot were determined to be positive for HSV-1 by Western Blot testing at the University of Washington. Overall agreement of 95.0% (554/583) was obtained between the two HSV-2 assay methods, with 95.7% (359/375) negative agreement and 96.1% (195/203) positive agreement.
Conclusions: The LIAISON HSV-1 IgG and LIAISON HSV-2 IgG Type Specific Assays showed overall diagnostic performance comparable to the Focus HerpeSelect 1 and 2 Immunoblot IgG Kit. In addition, agreement between the LIAISON HSV-1 IgG Assay and Western Blot analysis was demonstrated for a group of samples seen to be HSV-1 positive by LIAISON but negative by the Immunoblot. These results indicate that the LIAISON Assays generate accurate and reliable type specific diagnosis of herpes infections. In addition, the automated LIAISON platform offers time and cost savings to the laboratory.
