Performance evaluation of Elecsys HIV Duo on cobas e 801 using clinical samples in China

Clinical performance evaluation of an HIV Duo assay: From HIV screening to acute and non-acute HIV infection detection

BACKGROUND

Evaluating the clinical performance of Elecsys HIV Duo assay for primary human immunodeficiency virus (HIV) screening and acute HIV infection detection.

METHODS

This study was conducted from April 2022 to April 2023 and involved two distinct populations. For the HIV screening population, three HIV Duo results [HIV Duo, HIV antigen (Ag), and HIV antibody (Ab)] in primary screening were obtained (January 2021 to June 2021). In the diagnosed HIV population, retrospective samples from November 2016 to March 2023 were measured.

RESULTS

The HIV screening population included 111,383 samples from a real-world screening program. The assay demonstrated a specificity of 99.91 % (95 % CI: 99.89 %, 99.93 %) and a PPV of 0.8516 (95 % CI: 0.8225, 0.8776). Regarding the diagnosed HIV population, 836 HIV patients were enrolled, including 14 acute HIV infectious patients with only HIV Ag + and a Western Blot (WB) confirmation rate of 0 %. The median (IQR) of the numeric cut-off index (COI) ratios of HIV Duo Ab and Ag significantly differed among the Ag + Ab-, Ag-Ab+, and Ag + Ab + subgroups.

CONCLUSION

The Elecsys HIV Duo assay is suitable for primary HIV screening and can be integrated into a novel laboratory HIV testing algorithm to improve acute HIV detection in Chinese clinical practice.

ABBREVIATIONS

HIV, Human immunodeficiency virus; AIDS, acquired immunodeficiency syndrome; Ag, antigen; Ab, antibody; WB, Western Blot; COI, numeric cut-off index; CI, confidence interval; NAT, nucleic acid tests; EDC, electronic data capture systems; CDC, Chinese Centers for Disease Control and Prevention; IQR, interquartile range; PPV, positive predictive value; HCV, hepatitis C virus; HBV, hepatitis B virus; CI, confidence interval; ND, not able to define; F, female; M, male.

Clinical Application Evaluation of Elecsys® HIV Duo Assay in Southwest China

Background

HIV/AIDS continues to be a serious health concern of morbidity and mortality globally, and novel HIV testing is still an important component of diagnosing HIV earlier and reducing the spread of HIV. The Elecsys^® HIV Duo assay is a 4th generation assay that can detect both HIV-1 p24 antigen (Ag) and HIV-1/2 antibody (Ab) in parallel and show the subresults for the Ab and Ab units.

Objectives

To evaluate the clinical performance of the Elecsys^® HIV Duo assay on the new cobas E 801 analyzer using a large number of clinical samples from a population in southwest China.

Methods

We collected testing results and information from all patients in a large general hospital. All eligible clinical specimens were first analyzed using the Elecsys^® HIV Duo assay. The test results are given either as reactive or nonreactive as well as in the form of a cutoff index (COI). All initially reactive specimens were retested in duplicate with a 3rd-generation kit. Supplementary tests were divided into Ab confirmation tests and HIV-1 nucleic acid tests. GraphPad Prism and Python were used for plotting, and SPSS 21.0 software was used for statistical analysis.

Results

A total of 186391 specimens were received, and 436 patients were confirmed to be positive for HIV. Among the 86 cases with contact history available, there were more males than females, and heterosexual transmission was the most common route of HIV infection. The Elecsys^® HIV Duo assay displayed 99.94%, 99.93% and 99.98% specificity for inpatient, outpatient and physical examination patients, respectively. The median COI ratios of the false-positive group were significantly lower than those of the true-positive group.

Conclusions

The Elecsys^® HIV Duo test (Cobase801 analyzer) differentiates the detection of HIV-1 p24 Ag and HIV-1/2 Ab with high specificity and facilitates the diagnosis of patients with early HIV infection. Therefore, the Elecsys^®HIV Duo test is used for differentiation of antigen and antibody reactivity, making it suitable for routine clinical diagnosis.

Real-World Clinical Performance Evaluation of a Fourth-Generation HIV Antigen/Antibody Differentiation Test

BACKGROUND

HIV testing is still an important component of routine sexual health screening, assessment of at-risk individuals and as part of the care of pregnant women. To prevent further transmission of infection, it is important that HIV tests are highly sensitive and that positive cases are not missed. HIV serologic antigen/antibody tests are commonly used as they are capable of detecting recent and established infection.

METHODS

In this study we assessed the performance of the Elecsys HIV Duo assay (Elecsys assay) against the Abbott Architect assay in 10 121 samples from US and non-US adult, pediatric, and pregnant populations including low-risk, high-risk, and known positive cohorts. Congruent repeatedly reactive and/or discrepant samples followed a confirmatory algorithm consisting of an antigen/antibody differentiation assay and a nucleic acid test, as per the study protocol.

RESULTS

The overall sensitivity of the Elecsys assay was 100.00% (95% CI 99.81-100.00 [1977/1977]), and the specificity was 99.84% (95% CI 99.73-99.91 [8129/8142]). The Elecsys assay detected all positive samples within the study, including all 50 antigen-only positive samples and samples from different HIV subtypes, including group O, group M subtypes, HIV-2 positives, and HIV-1 and HIV-2 dual positives.

CONCLUSIONS

The Elecsys HIV Duo assay was highly sensitive for diagnosis of HIV in a range of clinical samples from the United States and outside the United States and is suitable for routine use.

Performance evaluation of Elecsys HIV Duo on cobas e 801 using clinical samples in China

The prevalence and incidence of human immunodeficiency viruses (HIV) infection are rapidly increasing, and novel HIV genotypes are emerging. This study evaluated the sensitivity and specificity of Elecsys HIV Duo assay in population with the epidemic of multiple genotypes of HIV-1 infection. Specificity of the Elecsys HIV Duo assay was determined using 3039 serum samples from patients receiving routine HIV-1 screening tests in China. Sensitivity was assessed with seroconversion panels. Additional 67 positive from newly diagnosed HIV-1 infected samples were also included to test assay performance on various HIV-1 genotypes. The assay performance was compared with that of the Elecsys HIV Combi PT assay. The genotypes of all HIV-1 positive samples were determined with phylogenetic analyses on the 1.1 kb Pro-RT region of pol gene for drug resistance tests. The Elecsys HIV Duo assay had a slightly higher specificity (99.93% vs 99.84%) and equivalent sensitivity to Elecsys HIV Combi PT assay. Seventy-two HIV-1 positive samples, including 12 antigens positive samples, were distinguished by Elecsys HIV Duo. Among them, 43 samples were circulating recombinant form (CRF)01_AE, followed by 13 of CRF07_BC, 10 of subtype B, 4 of URF_0107, 1 of URF_01B and 1 of CRF02_AG. The Elecsys HIV Duo assay showed good performance for the Chinese population with an epidemic of multiple HIV genotypes.