Evaluation of the vitros hiv combo 4th generation test for the identification of HIV infections.

Background: Simultaneous detection of HIV 1 and 2 antibodies and HIV-1 p-24 antigen in the 4th generation tests is particularly effective for the identification of early acute HIV infections while maintaining accurate detection of long-established infections.

Objectives: The aim of this study was to evaluate the new 4th generation VITROS HIV Combo test from Ortho-Clinical Diagnostics by comparing its results with those obtained using a 3rd generation HIV 1/2 antibody test (VITROS Anti HIV 1 + 2 from Ortho-Clinical Diagnostics) and a 4th generation test (LIAISON XL HIV Ab/Ag, DiaSorin) currently used in the Microbiology Unit of Legnano Hospital.

Study Design: One thousand and three samples of the normal daily routine (Group 1) were analyzed simultaneously with the three systems.

Threshold value of LIAISON XL anti-HCV screening assay predicting positive immunoblotting results.

Some international guidelines recommend evaluating the need to confirm positive anti-hepatitis C virus (HCV) antibody screening results by means of a more specific antibody or molecular biology test on the basis of a screening threshold value (such as the sample signal/cut-off ratio) that can predict the positivity of additional antibody testing in at least 95% of cases. The aim of this study was to determine the threshold value of the DiaSorin LIAISON XL chemiluminescence test. Two hundred and twenty-eight routine laboratory samples that were chemiluminescence positive for anti-HCV antibodies but had different signal/cut-off ratios were assayed using immunoblotting, which indicated that 155 (68.

Evaluation of LIAISON® XL system for HBsAg, and anti-HCV and anti-HIV/Ag p24.

The aim of this study was to compare the data obtained using the new LIAISON® XL chemiluminescence system to search for HBsAg, anti-HCV, and anti-HIV1-2/p24 Ag with those obtained using the VITROS system currently adopted by the Microbiology Unit of the Hospital of Legnano. Routine samples of patients who were referred by practitioners for the determination of HBsAg (1,000 samples) and/or anti-HCV (1,002 samples) and/or anti-HIV1-2 (995 samples) were simultaneously analyzed using both systems. The concordant positive and discordant samples were re-examined for confirmation by means of an HBsAg neutralization assay, anti-HCV immunoblot, or anti-HIV1-2 Western blot; HBV-DNA, or HCV-RNA or HIV-RNA was also sought in the discordant samples.

Prevalence of markers of hepatitis B virus infection or vaccination in HBsAg-negative subjects.

Background: The implementation of mass vaccinations against hepatitis B virus (HBV) has significantly reduced the prevalence of HBsAg-positive subjects. At the same time, the prevalence of the other markers of infection has decreased, but there has been an increase in the percentage of subjects with markers of a successful vaccination. It has been suggested that increasing immigration from countries in which this virus is highly endemic is changing the epidemiology of HBV infection.

Revision of the positive predictive value of IgM anti-Toxoplasma antibodies as an index of recent infection.

The severity of congenital Toxoplasma gondii infection underlines the need for a precise diagnosis of acute infection during pregnancy. The search for specific IgM has been widely used for this purpose, but their possible early disappearance or persistence over time limits their meaning. In order to estimate the positive predictive value of anti-Toxoplasma IgM testing, we made an epidemiological analysis of the presence of anti-Toxoplasma IgG and IgM using ELISA in 4786 subjects attending the Hospital of Legnano in 2004-2005: 1360 seen for a clinical check-up and 3426 pregnant women for serological screening.