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Background Early detection of acute HIV infection by HIV antigen/antibody assays depends on antigen sensitivity. Maintaining consistently high sensitivity across diverse HIV strains is critical to ensure equal detection. Objectives The performance of an improved HIV antigen/antibody prototype, HIV Combo Next, was evaluated for detection of genetically-diverse HIV strains and seroconversion samples. Study design Antigen sensitivity of the prototype was evaluated and compared to five FDA-approved HIV antigen/antibody assays using World Health Organization (WHO) HIV p24 antigen standard and reference panels, 17 virus isolates and 9 seroconversion panels. Antibody sensitivity and assay specificity of the prototype were also assessed with 1062 disease-staged and genotyped samples, and samples from 3000 blood donors and 955 individuals with low-risk for HIV infection. Results Compared with other assays evaluated, the prototype demonstrated the best analytical sensitivity for WHO antigen standard, reference panels including 12 HIV-1 variants (0.04 – 0.25 IU/ml) and one HIV-2 variant, and 17 HIV virus isolates including HIV-1 group M, N, P and O and HIV-2 (0.3 -16 pg/ml). The enhanced sensitivity was also observed for seroconversion samples, detecting more PCR-positive samples with detection up to 7 days earlier than the other assays. Improvement in antigen sensitivity did not compromise antibody sensitivity or assay specificity, detecting all HIV disease-staged and genotyped samples, with assay specificity of 99.97% for blood donors and 99.68% for the low-risk population. Conclusions These data indicate that the new prototype HIV Combo Next assay will be of diagnostic value, providing improved early detection for acute HIV infection from divergent HIV strains.

Background More and more countries test for HIV infection using combination assays that simultaneously detect p24 antigen and HIV antibodies. Objective To assess the performance of a new HIV combo assay: LIAISON ® XL murex HIV Ab/Ag HT. Study design The assays were examined with a total of 3090 samples that included 769 selected HIV antibody-negative samples, 1849 unselected HIV samples, 15 HIV-1 p24 Ag reference samples, 90 primary HIV-1 infection (PHI) samples, 167 HIV-1 antibody-positive samples (well characterized of groups M and O), 95 HIV-1 antibody-positive samples and 105 HIV-2 antibody-positive samples. Results The specificity of the LIAISON ® XL murex HIV Ab/Ag HT was 99.7%. The analytical sensitivity of Ag p24 of the LIAISON ® XL murex HIV Ab/Ag HT was 0.58 IU/mL and 9.93 pg/mL when using WHO and French national standards, respectively. All screened HIV subtypes was identified by this assay. Also, 90 PHI specimens were detected by this screening assay. Conclusion The sensitivity and specificity of the LIAISON ® XL murex HIV Ab/Ag HT assay are high. Hence the assay offers automated high-throughput screening with ability to detect primary infection.

Candida species bloodstream isolates were collected from institutions participating in an active, population-based surveillance for candidemia. Species identifications were performed locally and then confirmed at the Centers for Disease Control and Prevention (CDC) by phenotype-based methods. Discrepancies in species identification between the referring institution and the CDC were noted for 43 of 935 isolates (4.6%). A DNA probe-based species identification system (PCR-enzyme immunoassay [EIA]) was then used to resolve these discrepancies. The PCR-EIA result was identical to the CDC phenotypic identification method for 98% of the isolates tested. The most frequently misidentified species was Candida glabrata (37% of all discrepant identifications). Such misidentifications could lead to the administration of inappropriate therapy given the propensity of C. glabrata to develop resistance to azole antifungal drugs.