Performance evaluation of the Bio-Rad Geenius HIV 1/2 supplemental assay

Evaluation of the VioOne HIV profile supplemental assay

HIV is an ongoing global epidemic with estimates of more than a million new infections occurring annually. To combat viral spread, continuous innovations in areas including testing and treatment are necessary. In the United States, the Centers for Disease Control and Prevention recommend that laboratories follow an HIV testing algorithm that first uses a US Food and Drug Administration approved immunoassay to detect antibodies to HIV-1 or HIV-2 as well as HIV-1 p24 antigen in serum or plasma samples. An initially reactive specimen is tested by a supplemental assay for confirmation and to differentiate antibodies to HIV-1 or HIV-2. There are few Food and Drug Administration (FDA)-approved supplemental differentiation tests currently available. A multicenter investigation was conducted to determine the clinical performance for two independent versions of the Avioq VioOne HIV Profile Supplemental Assay (Avioq, Inc., Research Triangle Park, NC). The performance of both assay versions compared favorably with the performance parameters for the Geenius HIV 1/2 Supplemental Assay as published in that assay package insert (Bio-Rad Laboratories, Hercules, CA), the current gold standard for HIV supplemental testing. When comparing the two VioOne assays, version 2 (lacking HIV-2 p27 antibody detection) demonstrated improved reproducibility, specificity, and sensitivity as compared to its predecessor. IMPORTANCE We evaluated the reproducibility, sensitivity, and specificity data for two versions of the VioOne HIV Profile Supplemental Assay and compared these results back to similar results for the Geenius HIV 1/2 Supplemental Assay that are publicly available. Our study concluded that the VioOne HIV Profile Supplemental Assay compared favorably with the Geenius HIV 1/2 Supplemental Assay, thus providing an additional option for clinical laboratories to improve and expand their HIV testing capabilities.

Are Confirmatory Assays Reliable for HIV-1/HIV-2 Infection Differentiation? A Multicenter Study

Immunoblots remain the gold standard for HIV-1/HIV-2 infection confirmation. However, their ability to differentiate HIV-1 from HIV-2 infection on an antigenically diversified HIV-1 and HIV-2 panel remain uncommon. We performed a multicenter study on 116 serum samples accounting for most of the diversity of HIV-1 (9 different subtypes in group M, 17 circulating recombinant forms (CRFs), and 3 group O) and HIV-2 (groups A and B), evaluating seven confirmatory assays (six commercially available assays and one in-house assay) with genotyping as the reference. The assays were INNO-LIA HIV I/II score, HIV-2 blot 1.2, HIV blot 2.2, New Lav blot I and II, Geenius, and an in-house serotyping enzyme-linked immunosorbent assay (ELISA). Among the HIV-1 samples, INNO-LIA, HIV blot 2.2, New Lav blot I, Geenius, and serotyping had comparable high sensitivities, from 98% to 100%, whereas HIV-2 blot 1.2 and New Lav blot II had high rates of "undetermined" results (85% and 95%, respectively). HIV-2 blot 1.2 and New Lav blot II misclassified 7% and 5% of HIV-1 samples as HIV-2, respectively, and HIV-2 blot 1.2 had an 8% false-negative rate. Among the HIV-2 samples, INNO-LIA, New Lav blot II, HIV-2 blot 1.2, and serotyping had high sensitivities, from 96% to 100%. HIV blot 2.2 misclassified 17% of HIV-2 samples as HIV-1/HIV-2 dual infections. New Lav blot I misclassified 19% of HIV-2 samples as HIV-1 with a high (81%) undetermined rate, and Geenius misclassified 2% as HIV-1 and 7% as untypeable HIV positive. For HIV-1/HIV-2 dual infection, the results were less sensitive, with at most 87.5% for INNO-LIA and Geenius and 75% for HIV blot 2.2 and serotyping. Overall, confirmatory assays remain useful for most cases, with the exception of HIV-1/HIV-2 dual-infection suspicion.

Review of HIV Self Testing Technologies and Promising Approaches for the Next Generation

The ability to self-test for HIV is vital to preventing transmission, particularly when used in concert with HIV biomedical prevention modalities, such as pre-exposure prophylaxis (PrEP). In this paper, we review recent developments in HIV self-testing and self-sampling methods, and the potential future impact of novel materials and methods that emerged through efforts to develop more effective point-of-care (POC) SARS-CoV-2 diagnostics. We address the gaps in existing HIV self-testing technologies, where improvements in test sensitivity, sample-to-answer time, simplicity, and cost are needed to enhance diagnostic accuracy and widespread accessibility. We discuss potential paths toward the next generation of HIV self-testing through sample collection materials, biosensing assay techniques, and miniaturized instrumentation. We discuss the implications for other applications, such as self-monitoring of HIV viral load and other infectious diseases.

An HIV Diagnostic Testing Algorithm Using the cobas HIV-1/HIV-2 Qualitative Assay for HIV Type Differentiation and Confirmation

Human immunodeficiency virus types 1 and 2 (HIV-1 and HIV-2) diagnostic testing algorithms recommended by the Centers for Disease Control involve up to three tests and rely mostly on detection of viral antigen and host antibody responses. HIV-1 p24 antigen/HIV-1/HIV-2 antibody-reactive specimens are confirmed with an immunochromatographic HIV-1/HIV-2 antibody differentiation assay, and negative or indeterminate results from the differentiation assay are resolved by an HIV-1-specific nucleic acid amplification test (NAT). The performance of a proposed alternative algorithm using the cobas HIV-1/HIV-2 qualitative NAT as the differentiation assay was evaluated in subjects known to be infected with HIV-1 (n = 876) or HIV-2 (n = 139), at low (n = 6,017) or high (n = 1,020) risk of HIV-1 infection, or at high-risk for HIV-2 infection (n = 498) (study A). The performance of the cobas HIV-1/HIV-2 qualitative test was also evaluated by comparison to an HIV-1 or HIV-2 alternative NAT (study B). The HIV-1 and HIV-2 overall percent agreements (OPA) in study A ranged from 95% to 100% in all groups. The positive percent agreements (PPA) for HIV-1 and HIV-2 were 100% (876/876) and 99.4% (167/168), respectively, for known positive groups. The negative percent agreement in the HIV low-risk group was 100% for both HIV-1 and HIV-2. In study B, the HIV-1 and HIV-2 OPA ranged from 99% to 100% in all groups evaluated (n = 183 to 1,030), and the PPA for HIV-1 and HIV-2 were 100% and 99.5%, respectively, for known positive groups. The cobas HIV-1/HIV-2 qualitative assay can discriminate between HIV-1 and HIV-2 based on HIV RNA and can be included in an alternative diagnostic algorithm for HIV.

Performance of an Alternative Laboratory-Based HIV Diagnostic Testing Algorithm Using HIV-1 RNA Viral Load

BACKGROUND

Since 2014, the recommended algorithm for laboratory diagnosis of HIV infection in the United States has consisted of an HIV-1/2 antigen/antibody (Ag/Ab) test followed by an HIV-1/2 antibody (Ab) differentiation test and, if necessary, a diagnostic HIV-1 nucleic acid test to resolve discordant or indeterminate results.

METHODS

Using stored specimens from persons seeking HIV testing who had not received a previous diagnosis or treatment, we compared the performance of a 3-step alternative algorithm consisting of an Ag/Ab test followed by a quantitative HIV-1 RNA viral load assay and, if viral load is not detected, an Ab differentiation test, to that of the recommended algorithm. We calculated the sensitivity and specificity of 5 Ag/Ab tests and the proportion of specimens correctly classified by the alternative algorithm compared with the recommended algorithm. Results were examined separately for specimens classified as early infection, established infection, and false-reactive screening.

RESULTS

Sensitivity and specificity were similar among all Ag/Ab tests. Viral load quantification correctly classified all specimens from early infection, all false-reactive screening specimens, and the majority of specimens from established infection.

CONCLUSIONS

Although cost, regulatory barriers, test availability, and the ability to differentiate early from established infection must be considered, this alternative algorithm can potentially decrease the total number of tests performed and reduce turnaround time, thereby streamlining HIV diagnosis and initiation of treatment.

Could HIV-1 RNA Testing be an Option as the Second Step in the HIV Diagnostic Algorithm?

BACKGROUND

There is benefit to early HIV-1 diagnosis and treatment, but there is no Food and Drug Administration-approved quantitative assay with a diagnostic claim. We compared the performance of the Hologic Aptima HIV-1 Quant (APT-Quant) and Aptima HIV-1 Qual (APT-Qual) assays for diagnostic use and the performance of a diagnostic algorithm consisting of Bio-Rad BioPlex 2200 HIV Ag-Ab assay (BPC) followed by APT-Quant (2-test) compared with BPC followed by Geenius HIV-1/2 supplemental assay (Geenius) with reflex to APT-Qual (3-test).

METHODS

Five hundred twenty-four plasma, which included 419 longitudinal specimens from HIV-1 seroconverters (78 were after initiating antiretroviral therapy [ART]) and 105 from ART-naive persons with established HIV-1 infections, were used to evaluate APT-Quant performance for diagnostic use. Specimens from 200 HIV-negative persons were used to measure specificity. For the algorithm comparison, BPC-reactive specimens were evaluated with the 2-test or 3-test algorithm. McNemar's test was used to compare performance.

RESULTS

The APT-Quant detected more samples early in infection compared with APT-Qual. The APT-Quant specificity was 99.8%. Before ART initiation, the algorithms performed similarly among samples from different stages of infection. After ART initiation, the 3-test algorithm performed significantly better (P = 0.0233).

CONCLUSIONS

The APT-Quant has excellent performance for diagnostic use. The 2-test algorithm works well in ART-naive samples, but its performance decreases after the IgG response is elicited and with ART-induced suppressed viremia. Providing confirmation and viral load assay with 1 test result could be advantageous for patient care. However, additional factors and challenges associated with the implementation of this 2-test algorithm, such as cost, specimen type, and collection need further evaluation.

Verification and Implementation of HIV Antibody Differentiation Testing to Improve Turnaround Time for the HIV Diagnostic Algorithm

BACKGROUND

Relying on reference laboratories for HIV confirmation testing may lead to delays in treatment and can cause stress for patients who have positive HIV screening results.

OBJECTIVE

To internalize HIV-1/HIV-2 antibody differentiation testing within the hospital laboratory.

METHODS

We analytically verified an HIV antibody differentiation immunoassay and subsequently compared result turnaround times (TATs) for HIV antibody differentiation and HIV-1 qualitative RNA in the months before and after the test internalization.

RESULTS

HIV antibody differentiation was successfully verified. TATs for HIV antibody differentiation and HIV-1 RNA significantly improved, from medians of 40.4 hours and 156.5 hours to medians of 17.7 hours and 56.5 hours, respectively, after the internalization. The 90th-percentile turnaround times declined by 72% and 44%, respectively.

CONCLUSIONS

It is feasible for a hospital laboratory to verify HIV antibody-differentiation testing. Its implementation may considerably improve result TATs for the HIV diagnostic algorithm.

Assessing donor suitability for blood donation: Utility of Geenius HIV 1/2 confirmatory assay

BACKGROUND

Blood donor care and blood safety require a quick and accurate decision on the presence or absence of Human Immunodeficiency Virus (HIV) infection, based on the proper selection of blood donors, serological and molecular HIV testing as well as western blot test. The aim was investigating the possibility of inclusion of Geenius HIV 1/2 Confirmatory Assay in blood donor testing algorithm in order to shorten test time and decrease the number of indeterminate results.

METHODS

A total of 75 archived serum/plasma samples were tested. Their previous serological and molecular HIV results were: 3 negative samples, 7 positive samples, 65 serological indeterminate or positive but confirmatory testing and NAT negative samples.

RESULTS

Geenius assay confirmed the presence of antibodies in all blood donors with HIV positive serology and Nucleic Acid Testing (NAT). HIV-1 gp160 and gp41 antibodies were detected in these donors, while p31 and p24 antibodies were not detected in two and three donors, respectively. HIV-2 antibodies gp36 and gp140 were not found. Blood donor with HIV indeterminate or positive serology but negative confirmatory testing and NAT, were negative in Geenius assay. Conclusion The results obtained are consistent with western blot results. The assay proved simple and quick to perform. Studies have confirmed the possibility of introducing Bio-Rad Geenius into a routine blood donor testing protocol.