Development and Validation of Three Automated High-Throughput Molecular Tests to Detect Monkeypox Virus Infections.

BACKGROUND: The 2022 outbreak of the clade IIb monkeypox virus and subsequent global spread lead to an urgent need for the development of high-throughput, sensitive, and reproducible diagnostic tests. METHODS: We developed 3 assays to detect monkeypox virus, 2 (MPXV+ and MPXV) for m2000 RealTime and 1 (MPXV) for Alinity m platforms. Dual targets in E9L and B6R (MPXV+) and J2L and B7R (MPXV) increased mutation resistance. In silico prediction indicates MPXV+ cross-reactivity with orthopox viruses and specific monkeypox virus detection with MPXV. RESULTS: m2000 RealTime MPXV+ and MPXV assay sensitivity was determined to be 3.2 plaque-forming units/mL using a reference virus culture diluted into universal transport medium (UTM). Alinity m MPXV lower limit of detection was 200 copies/mL using monkeypox virus plasmids in pooled UTM matrix. m2000 RealTime MPXV+ and MPXV assays were validated with lesion swabs in UTM and 1:1 saliva to UTM mixtures. Commercially available and remnant clinical lesion specimens in UTM were tested with RealTime MPXV+, RealTime MPXV and Alinity m MPXV assays and demonstrated high agreement to known mpox (MPX)-positive specimens. CONCLUSIONS: RealTime MPXV+, RealTime MPXV, and Alinity MPXV are high throughput and sensitive assays used for the detection of monkeypox virus. These assays maybe useful during MPX outbreaks.

Clinical and Analytical Evaluation of the Alinity m HR HPV Assay within the VALGENT-3 Framework.

Only clinically validated human papillomavirus (HPV) tests should be used in cervical cancer screening. VALGENT provides a framework to validate new HPV tests. In the VALGENT-3 study, the clinical accuracy of the recently launched Abbott Alinity m HR HPV assay (Alinity m) to detect cervical precancerous lesions was assessed against the standard comparator test (Hybrid Capture 2; HC2) and against two previously validated alternative comparator tests (Abbott RealTime HR HPV and Roche cobas 4800 assays). Validation was conducted using 1,300 consecutive cervical samples from women attending an organized population-based cervical screening program enriched with 300 cytologically abnormal samples. Overall high-risk HPV test concordance was assessed by kappa values; the concordance for HPV-16 and HPV-18 was assessed for Alinity m, RealTime, and cobas, and the Linear Array (Roche) was used for more detailed genotyping concordance. In the total study population, the relative sensitivity and specificity for cervical intraepithelial neoplasia grade 2 or worse (CIN2+) and CIN3+ of Alinity m compared to HC2 was 1.02 (95% confidence interval [CI], 0.99 to 1.06) and 1.03 (95% CI, 0.99 to 1.06), respectively. The relative specificity for nondiseased subjects (≤CIN1) was 1.01 (95% CI, 1.00 to 1.02) (all pnon-inferiority ≤ 0.001). Alinity m showed noninferior clinical accuracy among women 30 years or older when cobas or RealTime was used as a comparator. HPV genotype-specific concordance between Alinity m and the three comparator tests showed excellent agreement, with kappa values ranging from 0.82 to 1.00. In conclusion, Alinity m fulfills the international accuracy requirements for use in cervical cancer screening and shows excellent HPV genotype-specific concordance with three clinically validated HPV tests.

Evaluation of the analytical and clinical performance of the Abbott Alinity m instrument for the quantification of HIV-1 RNA plasma viral load in a reference laboratory in Rio de Janeiro, Brazil.

OBJECTIVES: We sought to evaluate the analytical performance of the Alinity m system (Abbott Molecular) and to compare the clinical performance of HIV-1 assays on the Alinity m and m2000 RealTime platforms (Abbott Molecular). METHODS: The sensitivity, precision, and accuracy of the Alinity m instrument were determined using a panel of standard samples (n = 46). The carryover effect was assessed by analyzing HIV-negative clinical samples (n = 20). Clinical performance of the Alinity m and m2000 RealTime platforms was compared using surplus HIV-positive patient plasma samples (n = 39). RESULTS: The Alinity m HIV-1 assay demonstrated 100% sensitivity, a high precision (coefficient of variation (s/x̄) × 100 ≤1.5% [SD ≤ 0.05] logarithm to base 10 [log10] copies/mL), and partial accuracy over the quantification range. Analysis of clinical samples suggested that the Alinity m HIV-1 assay does not cause carryover effect and produced a mean bias of 0.209 log10 copies/mL (95% CI, 0.153-0.265) compared with the m2000 RealTime System. CONCLUSIONS: The Alinity m instrument's performance correlated to that of the m2000 RealTime platform and showed excellent sensitivity, precision, and accuracy, despite producing overquantification not clinically relevant for disease management. Furthermore, use of the Alinity m platform can reduce turnaround time.

Clinical Evaluation of Xpert Xpress CoV-2/Flu/RSV plus and Alinity m Resp-4-Plex Assay.

The performance of the Xpert Xpress CoV-2/Flu/RSV plus and Alinity m Resp-4-Plex Assays were evaluated using 167 specimens, including 158 human respiratory specimens and 9 external quality assessment program (EQAP) samples. For respiratory specimens, CoV-2/Flu/RSV plus exhibited perfect agreement with the standard-of-care (SOC) methods (Cohen's κ: 1, 100% agreement). The overall positive and negative percent agreement (PPA and NPA) were 100%, with 95% confidence intervals of 96.50 to 100% and 85.70 to 100%, respectively. On the other hand, Resp-4-Plex revealed an almost perfect agreement with the SOC methods (Cohen's κ: 0.92, 97.71% agreement). The overall PPA and NPA were 100% (95.76 to 100%) and 88.46% (70.20 to 96.82%), respectively. For EQAP samples, the results of CoV-2/Flu/RSV plus (9/9) and Resp-4-Plex (4/4) were concordant with the expected results. The experimental limit of detection of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) was the lowest (25 copies/mL for both methods), and that of the respiratory syncytial virus was the highest (400 copies/mL for CoV-2/Flu/RSV plus and 100 copies/mL for Resp-4-Plex). Threshold cycle (Ct) value correlation showed a large positive linear association between CoV-2/Flu/RSV plus and Resp-4-Plex, with R-squared values of 0.92-0.97, and on average, the Ct values of CoV-2/Flu/RSV plus were higher than that of Resp-4-Plex by 1.86-2.78, except for Flu A1 target (-0.66). To conclude, the performance of both assay was comparable to the SOC methods for both upper and lower respiratory specimens. Implementation of these rapid assay may reinforce the diagnostic capacity for the post-pandemic co-circulation of SARS-CoV-2 and other respiratory viruses.

Clinical comparison of three SARS-CoV-2 nucleic acid amplification tests for routine diagnostic testing.

Background: Cycle threshold (Ct) values from SARS-CoV-2 nucleic acid amplification tests have been used to estimate viral load for treatment decisions. Additionally, there is a need for high-throughput testing, consolidating a variety of assays on one random-access analyzer. Objectives: In this study, the clinical performance of the Alinity m SARS-CoV-2, RealTime SARS-CoV-2, and GeneXpert Xpress SARS-CoV-2/Flu/RSV assays was assessed. Methods: Alinity precision and detection rates were evaluated using a dilution series of the Alinity m SARS-CoV-2 positive control. In a retrospective study, 7 remnant external quality assessment (EQA) specimens and 200 remnant nasopharyngeal swab specimens (100 positive and 100 negative) were tested in the three assays. Results: Alinity had 100 % detection rate at 50 copies/mL and high reproducibility (Ct value coefficient of variation ≤3.1 %). All three assays correctly detected positive and negative EQA samples with comparable Ct values (max difference 2.38) and high linearity. In patient samples, positive percent agreement was 95 % (95 % CI 89-98 %) and negative percent agreement was 100 % (95 % CI 96-100 %) for Alinity, compared to the other two assays. Four specimens detected on Alinity m but not RealTime or Xpert had Ct values above 40. Assay results were highly correlated (r ≥ 0.94). Ct values (after addition of 10 unread cycles to the reported Ct of RealTime) were comparable across the three assays. Conclusions: Alinity m had high precision and accuracy and Ct values comparable to those of the RealTime and Xpert assays. The assays could be used interchangeably, with no need for adjustment of patient management decisions based on Ct values from each assay.

Clinical evaluation of the automated Abbott RealTime SARS-CoV-2, Alinity m SARS-CoV-2, and Alinity m Resp-4-Plex assays.

BACKGROUND: Detection of SARS-CoV-2 infections relies on the use of sensitive, accurate and high throughput RT-PCR assays. OBJECTIVES: We assessed the analytical performance of the Abbott RealTime SARS-CoV-2 (RT-SARS), Alinity m SARS-CoV-2 (AlinSARS) assays and compared the clinical performance of the RT-SARS, AlinSARS, and Alinity m Resp-4-Plex (Alin4Plex) assays to the Seegene Allplex assay (Allplex) and an inhouse test (Inhouse). RESULTS: We found 100 % positive percent agreement (PPA) and 100 % negative percent agreement (NPA) comparing RT-SARS and Allplex. RT-SARS, AlinSARS and Inhouse showed 100 % NPA and 100 % PPA across all assays, except for the RdRp target of Inhouse (PPA = 84 %). Similarly, Alin4Plex and Allplex showed high agreement with specimens containing either SARS-CoV-2, influenza A, influenza B, or RSV. Detection rates of 100 % for SARS-CoV-2 at 50 copies/mL, high precision, and no cross-reactivity with non-SARS-CoV-2 respiratory pathogens were observed for RT-SARS and AlinSARS. AlinSARS detected SARS-CoV-2 in spiked throat washes and in specimens infected with SARS-CoV-2 Alpha or Beta variants. CONCLUSIONS: The newly developed RT-SARS, AlinSARS, and Alin4Plex assays proved to be useful for detecting SARS-CoV-2 RNA in clinical samples.

Performance evaluation of the fully automated molecular system Alinity m in a high-throughput central laboratory.

BACKGROUND: New partially or fully automated molecular diagnostic testing platforms are being developed to address the growing demand for fast, accurate, and cost-effective testing. OBJECTIVES: To evaluate the analytical and clinical performance of the Alinity m system compared to the Abbott RealTime m2000 assay system in a large central molecular laboratory. STUDY DESIGN: Alinity m HIV-1, HCV, and HBV assay precision, reproducibility, and sensitivity were assessed using commercial customized dilution panels. Clinical performance of the Alinity m and m2000 assay systems was compared using standard lab protocols and residual, de-identified patient specimens. A workflow analysis of 1,068 samples compared turnaround times (TATs) on five m2000 systems and one Alinity m system running Alinity m HIV-1, HCV, HBV, HR HPV, and STI assays. RESULTS: The Alinity m assay system demonstrated high detectability and precision at clinical decision points and excellent correlation with Abbott RealTime assay results. Processing TAT for 100 % of results was 117 min on Alinity m. Sample onboard TAT, from sample loading to 95 % of results, was 5:15 h for Alinity m and 7:30 h for m2000. 100 % of STAT samples were processed within 4 h on Alinity m. Total TAT for 100 % of results from all five assays was 80 h for m2000 versus 9 h for Alinity m. CONCLUSIONS: The Alinity m system produces assay results comparable to those of the Abbott RealTime m2000 system, but with significantly faster turnaround times due to continuous loading and the ability to run multiple assays simultaneously on the same sample.

Performance characteristics of the Abbott Alinity m SARS-CoV-2 assay.

Mass molecular diagnostic testing for the SARS-CoV-2 pandemic has drawn on laboratory developed tests, commercial assays, and fully-automated platforms to accommodate widespread demand. The Alinity m instrument by Abbott is capable of detecting several clinically relevant pathogens and has recently received FDA emergency use authorization for SARS-CoV-2 molecular testing. The Alinity m performs automatic sample preparation, RT-PCR assembly, amplification, detection, and result calculation in under two hours. Here, we validate the performance characteristics of the Alinity m SARS-CoV-2 assay in comparison with the Roche cobas 6800 and Hologic Panther Fusion platforms. Across 178 positive and 195 negative nasopharyngeal swab specimens (CT range 14.30-38.84), the Alinity m detected one additional positive specimen that was found to be negative on the Roche cobas 6800 (PPA 100%, NPA 99.5%). Across a separate set of 30 positive and 174 negative nasopharyngeal swab specimens (CT range 14.1-38.5), the Alinity m had 100% positive and negative agreement with the Hologic Panther Fusion. Using SeraCare SARS-CoV-2 RNA standards, the assay limit of detection was verified to be two-fold more sensitive than the parameters stated by the SARS-CoV-2 AMP kit package insert, at 50 virus copies/mL. Assay specificity was 100% over 20 specimens positive for other respiratory viruses and intraday precision was 100% concordant with <2% CV. These data illst u illustrate the Abbott Alinity m system's high concordance with reference assays and analyti high analytical for SARS-CoV-2 molecular detection.

Comparison of Alinity m HPV and cobas HPV assays on cervical specimens in diverse storage media.

OBJECTIVE: To assess the concordance of high-risk HPV (HR-HPV) testing with the Alinity assay on cervical samples collected with diverse collection/storage protocols (ThinPrep, SurePath, Cervicollect) and to assess inter-assay concordance of HR-HPV testing of cervical cell specimens with Alinity m HR HPV assay (Alinity) vs cobas® 4800 HPV assay (cobas). METHODS: Specimens were obtained from 560 women attending a Women's Health clinic. Two specimens were obtained from each woman with combinations of two of the three collection devices and aliquots were tested by the two assays. RESULTS: Alinity showed an agreement of 93.9%, Kappa = 0.89 (263/280) between ThinPrep and SurePath specimens; 97.5%, Kappa = 0.95 (347/356) and 92.9%, Kappa = 0.85 (104/112) between ThinPrep and SurePath aliquots taken before or after cytology processing, respectively. Cervi-Collect specimens showed an agreement of 94.6%, Kappa = 0.89 (265/280) with ThinPrep specimens. Compared to cobas, Alinity showed agreements of 94.3%, Kappa = 0.88 (395/419) and 91.8%, Kappa = 0.82 (257/280) between ThinPrep and SurePath specimens, respectively. Alinity and cobas detected genotypes 16/18 and other high-risk HPV types at similar rates and showed similar correlations with cytology grades. CONCLUSIONS: Compared to cobas, Alinity performed equally well for detecting HPV in cervical specimens obtained with ThinPrep and SurePath. The Cervi-Collect device compared well to the other collection methods. Alinity is a reliable assay for simultaneous detection of HPV-16/18 and other high-risk genotypes in cervical specimens.

Comparison of the Abbott Alinity m and m2000 assays for the quantification of HIV-1, HCV and HBV in clinical samples.

BACKGROUND: Viral load (VL) determination is an essential parameter of the management of patients infected with HIV, HBV or HCV. Many available molecular systems run on a "batch" mode while "random access" systems provide more flexibility. OBJECTIVES: We compared the performance of HIV-1, HCV and HBV quantification assays on the recently developed Abbott Alinity m system to the m2000 RealTime assays. STUDY DESIGN: Plasma specimens sent for viral load determination were prospectively tested on m2000 and Alinity m systems, according to manufacturers' instructions. Additional low and high tittered samples were used to assess reproducibility. RESULTS: Assays concordance was evaluated from 180 samples for HIV-1, 122 for HBV, and 92 for HCV. A good correlation and a linear relation over the quantification range was observed for the three markers (r > 0.974). The Alinity m assays yielded higher results with a mean quantification bias of 0.22 log cp/ml for 75 HIV-1, 0.3 log IU/ml for 79 HBV, and 0.2 log for 35 HCV samples, though results were equivalent within an allowable difference of 0.3-0.4 log. Qualitative discordance was observed for 43/180 HIV results, 10/122 HBV and 7/92 HCV and involved undetectable or low-level VL. CONCLUSION: The Alinity m assays have performance equivalent to m2000. Upon implementation, physicians should be aware of the relative overquantification compared to previous Abbott assays, particularly around clinical decision thresholds. With reduced turnarounds and hands-on times compared to the m2000 system, the Alinity m platform may improve significantly the laboratory workflow efficiency for the benefit of physicians and patients.

Evaluation of the Alinity m HIV-1 assay for the quantification of HIV-1 RNA plasma viral load in a high-throughput molecular laboratory in South Africa.

BACKGROUND: Regular HIV-1 viral load monitoring forms an essential part of any successful HIV-1 treatment programme. Abbott Molecular recently released the Alinity m HIV-1 assay to be run on the Alinity m System, a fully automated, continuous and random access analyser using ReadiFlex™ technology. OBJECTIVES: Our study investigated the performance of the Alinity m HIV-1 assay in comparison to the cobas® HIV-1 test in a high-throughput molecular laboratory. STUDY DESIGN: We compared the performance of the Alinity m HIV-1 assay with the cobas® HIV-1 test, performed on both the cobas® 4800 and cobas® 6800 systems at three clinically relevant thresholds (50, 200 and 1000 cp/mL). RESULTS: Excellent correlation (r = 0.98) and agreement (mean bias -0.004 Log10 cp/mL) was achieved between the cobas® 4800 and Alinity m HIV-1 assay. While there was good correlation between the Alinity m HIV-1 assay and the cobas® 6800 (r = 0.99), Bland-Altman analysis indicated that the cobas® 6800 on average measured 0.22 Log10 cp/mL higher than the Alinity m HIV-1 assay across the dynamic range. Percentage agreement was excellent at the 200 cp/mL and 1000 cp/mL thresholds and was slightly lower at 50 cp/mL in comparison with the cobas® systems. CONCLUSIONS: The Alinity m HIV-1 assay compared well with the cobas® HIV-1 test on both the cobas® 4800 and cobas® 6800 systems in a high-throughput molecular laboratory in South Africa, a low- to middle-income country.

Investigating utilising the Alinity m platform to detect hepatitis C virus RNA in dried blood spot samples.

BACKGROUND: Elimination of Hepatitis C virus (HCV) relies on increasing HCV diagnostic rates in hard to reach populations. Dried blood spot (DBS) samples are a convenient sample type for HCV testing, as they can be collected in non-traditional settings such as drug services and prison settings, increasing access to HCV testing. OBJECTIVES: Herein we investigate an off-label DBS protocol for use on the Abbott Alinity m platform. STUDY DESIGN: A dilution series of HCV RNA positive blood was used to determine the analytical sensitivity of the test. We assess the sensitivity and specificity of HCV RNA detection in 50 mock DBS specimens compared to associated plasma viral load, and re-test 66 clinical DBS, previously tested on the m2000 to determine the clinical sensitivity and specificity of the assay. RESULTS: The dilution panel suggested that the Alinity m DBS assay is one log more sensitive than our current DBS HCV RNA assay. Mock DBS demonstrated 100% specificity, and 100% sensitivity for samples with plasma HCV RNA viral loads > 2.7 log10 IU/mL, however four samples with viral loads between 1.3 and 2.4 log10 IU/mL were not detected. The clinical sensitivity and specificity of previously tested DBS was 94% and 100% respectively, with two samples reported as low level RNA positive on the m2000 testing negative on Alinty m. CONCLUSIONS: The data suggests that DBS can be used as an off-label specimen type on the Alinity m HCV assay. Allowing continuous, random access testing of DBS simultaneously alongside other Alintiy m assays, potentially improving test turn-around times.

Multicenter clinical comparative evaluation of Alinity m HIV-1 assay performance.

BACKGROUND: Accurate, rapid detection of HIV-1 RNA is critical for early diagnosis, treatment decision making, and long-term management of HIV-1 infection. OBJECTIVE: We evaluated the diagnostic performance of the Alinity m HIV-1 assay, which uses a dual target/dual probe design against highly conserved target regions of the HIV-1 genome and is run on the fully automated Alinity m platform. STUDY DESIGN: This was an international, multisite study that compared the diagnostic performance of the Alinity m HIV-1 assay to four commercially available HIV-1 assays routinely used in nine independent clinical laboratories. Alinity m HIV-1 assay precision, detectability, and reproducibility was compared across four study sites. RESULTS: The Alinity m HIV-1 assay produced comparable results to currently available HIV-1 assays (correlation coefficient >0.995), with an overall bias of -0.1 to 0.10 Log10 copies/mL. The Alinity m HIV-1 assay and its predecessor m2000 HIV-1 assay demonstrated comparable detection of 16 different HIV-1 subtypes (R2 = 0.956). A high level of agreement (>88 %) between all HIV-1 assays was seen near clinical decision points of 1.7 Log10 copies/mL (50 copies/mL) and 2.0 Log10 copies/mL (200 copies/mL). Alinity m HIV-1 assay precision was 0.08 and 0.21 Log10 copies/mL at VLs of 1000 and 50 copies/mL, respectively, with a high level of detectability (≥97 % hit rate) and reproducibility across sites. CONCLUSIONS: The Alinity m HIV-1 assay provides comparable diagnostic accuracy to current HIV-1 assays, and when run on the Alinity m system, has the capacity to shorten the time between diagnosis and treatment.