Molecular diagnosis of Cytomegalovirus infection: clinical performance of the Aptima transcription-mediated amplification assay toward conventional qPCR chemistry on whole blood samples.

Human Cytomegalovirus (HCMV) infection is life-threatening for immunocompromised patients. Quantitative molecular assays on whole blood or plasma are the gold standard for the diagnosis of invasive HCMV infection and for monitoring antiviral treatment in individuals at risk of HCMV disease. For these reasons, an accurate standardization toward the WHO 1st International Standard among different centers and diagnostic kits represents an effort for better clinical management of HCMV-positive patients. Herein, we evaluate, for the first time, the performance of a new transcription-mediated amplification (TMA) assay versus quantitative polymerase chain reaction (qPCR) chemistry, used as a routine method, on whole blood samples. A total of 755 clinical whole blood specimens were collected and tested simultaneously with TMA and qPCR assays. The data showed a qualitative agreement of 99.27% for positive quantified samples and 89.39% for those undetected between the two tested methods. Evaluation of viremia in positive samples highlighted a good correlation between TMA and qPCR chemistries in terms of International Units (ΔLog10 IU/mL: -0.29 ± 0.40). The TMA assay showed a significant correlation with qPCR in patients monitored for up to 3 months, thus allowing an accurate assessment of viremia in transplant patients. Therefore, TMA chemistry showed good agreement with qPCR testing, used as a current diagnostic routine. It also offers important advantages, such as FDA approval on plasma and In Vitro Diagnostic (IVD) on both plasma and whole blood, automated workflow with minimal hands-on time, and random access loading, thus enabling a rapid and reliable diagnostic in HCMV-infected patients. IMPORTANCE: In this paper, we describe the clinical performance of a novel transcription-mediated amplification (TMA) assay for the detection and quantification of human Cytomegalovirus (HCMV) DNA from whole blood samples. This is a pivotal analysis in immunocompromised patients [transplanted, HIV-positive, and Hematopoietic Stem Cell (HSC) recipients], and molecular tests with high sensitivity and specificity are necessary to evaluate the HCMV viral load in these patients. To our knowledge, this is the first in-depth evaluation of TMA chemistry for HCMV diagnosis on whole blood samples. Moreover, also technical aspects of this assay make it suitable for clinical diagnostics.

Prevalence of genital high-risk human papillomavirus infections and associated factors among women living with human immunodeficiency virus in Uganda.

BACKGROUND: Women living with HIV are at risk for cervical dysplasia and cancer worldwide. In 2015, the World Health Organization (WHO) recommended that testing for high-risk HPV (hrHPV) infection be incorporated into cervical cancer screening programs using molecular nucleic acid tests (NATs) but this has not previously been done in Uganda. The country's coverage for Human Papilloma Virus (HPV) screening remains low at less than 10% for women aged 25-49 years. This study determined the genital prevalence of hrHPV infection and the associated factors among women living with HIV in Uganda. METHODS: A descriptive cross-sectional study was conducted in 15 selected health facilities among participants who were on Antiretroviral therapy (ART). Participants who consented to participate were instructed on how to collect their own high vaginal swabs using a cervical brush for HPV molecular testing (HPV DNA or HPV RNA) and their demographics data was collected using a standard questionnaire. Laboratory diagnosis for HPV molecular testing was done using Gene xpert machines and Hologic Aptima Machine. Modified Poisson regression analysis was conducted to determine the associated factors. RESULTS: This study involved 5856 HIV positive participants on ART. A total of 2006 out of 5856 (34.3%) participants had high risk HPV infections. HPV infections by genotypes were: HPV16 317(15.8%), HPV 18/45 308 (15.4%) and other high-risk HPV 1381 (68.8%). The independent factors associated with all hrHPV were parity, education level, having more than one partner, and engaging in early sex. Smoking was associated with HPV 16, HPV 18/45 and other hrHPV. Age was associated with all hrHPV, marital status with HPV 16, and occupation with HPV 16. CONCLUSIONS: The prevalence of genital high-risk HPV infections among HIV positive women attending ART clinics in public facilities in Uganda was high. Other hrHPV genotype was the commonest compared to 18/45 and HPV 16. The integration of cervical cancer screening in ART programmes remains paramount to support the early detection of cervical cancer and Non-invasive self-collected urine and vaginal sampling for cervical cancer screening present an opportunity.

Evaluation of Performance Characteristics of the Aptima CMV Quant Assay for the Detection and Quantitation of CMV DNA in Plasma Samples.

Quantification of Cytomegalovirus (CMV) DNA has become the standard of care in the diagnosis and management of CMV infection in transplant recipients. The objective of the study was to evaluate performance characteristics of the Aptima CMV Quant assay in comparison to Abbott RealTime CMV assay, Qiagen Artus CMV RGQ MDx assay, and Roche cobas CMV test using plasma samples. The performance of the Aptima assay was evaluated by comparing the Exact Diagnostics CMV verification panel and positive controls, Hologic CMV internal reproducibility panel, and SeraCare CMV DNA qualification panel to the RealTime assay. Clinical agreement was evaluated using 389 clinical plasma samples comparing the Aptima assay to three comparator assays. The Aptima assay demonstrated good linearity and strong linear correlation between the assays (R2 = 0.99); the intra- and interassay reproducibility was excellent overall (SD = 0.09 to 0.14 and SD = 0.04 to 0.14, respectively); 95% limit of detection (LOD) is 32 IU/mL and LOQ is 45 IU/mL. The SeraCare qualification panel yielded a strong linear correlation (R2 = 0.99). A total of 262 positive samples were analyzed to compare Aptima and Realtime assays using Deming regression and Bland-Altman analysis and demonstrated a mean bias of 0.092 Log10 IU/mL. Artus (85) and cobas (159) positive samples were compared to the Aptima assay using Deming regression and Bland-Altman analyses and showed mean bias of 0.184 and -0.208 Log10 IU/mL, respectively. The findings demonstrate that the Aptima assay is sensitive and accurate in quantifying CMV in plasma specimens on the fully automated Panther system and that the results were comparable to the other FDA-approved CMV assays.

Assessment of the clinical and analytical performance of the Aptima SARS-CoV-2 assay using the VALCOR protocol.

BACKGROUND: The COVID-19 pandemic highlighted the importance of diagnostic testing against curbing the spread of SARS-CoV-2. The urgent need and scale for diagnostic tools resulted in manufacturers of SARS-CoV-2 assays receiving emergency authorization that lacked robust analytical or clinical evaluation. As it is highly likely that testing for SARS-CoV-2 will continue to play a central role in public health, the performance characteristics of assays should be evaluated to ensure reliable diagnostic outcomes are achieved. METHODS: VALCOR or "VALidation of SARS-CORona Virus-2 assays" is a study protocol designed to set up a framework for test validation of SARS-CoV-2 virus assays. Using clinical samples collated from VALCOR, the performance of Aptima SARS-CoV-2 assay was assessed against a standard comparator assay. Diagnostic test parameters such as sensitivity, specificity and overall per cent agreement were calculated for the clinical performance of Aptima SARS-CoV-2 assay. RESULTS: A total of 180 clinical samples were tested with an addition of 40 diluted clinical specimens to determine the limit of detection. When compared to the standard comparator assay Aptima had a sensitivity of 100.0% [95% CI 95.9-100.0] and specificity of 96.7% [95% CI 90.8-99.3]. The overall percent agreement was 98.3% with an excellent Cohen's coefficient of κ = 0.967 [95% CI 0.929-1.000]. For the limit of detection, Aptima was able to detect all of the diluted clinical samples. CONCLUSION: In conclusion. validation of Aptima SARS-CoV-2 assay using clinical samples collated through the VALCOR protocol showed excellent test performance. Additionally, Aptima demonstrated high analytical sensitivity by detecting all diluted clinical samples corresponding to a low limit of detection.

Human papillomavirus self-sampling with mRNA testing benefits routine screening.

High risk human papillomavirus (hrHPV) based screening provides the possibility of vaginal self-sampling as a tool to increase screening attendance. In order to evaluate the impact and feasibility of opt-in self-sampling in the Finnish setting, we invited a randomized population of 5350 women not attending screening after age group invitation or after reminder, to attend HPV self-sampling-based screening in the autumn of 2018 in Helsinki. Out of those, 1282 (24.0%) expressed their interest and ordered the sampling package. Eventually 787 women (14.7% of the total invited population) took part in screening, 770 women by providing a vaginal sample within 2 months from invitation and 17 by providing a pap smear in the laboratory. Self-taken samples were collected in Aptima Multitest vials and tested using the Aptima HPV mRNA assay. A high proportion, 158/770 (20.5%) of the samples were positive in the Aptima HPV assay. One hundred and forty-one samples were further submitted to Aptima HPV Genotyping and extended genotyping by a Luminex based assay. Of those, 23 samples (16.3%) were HPV 16 positive and 7 (5.0%) were positive for HPV 18/45; extended genotyping revealed multiple high-risk and low-risk HPV genotypes. At follow-up seven cases of high-grade squamous intraepithelial lesion (HSIL) were diagnosed, which represents 4.4% of HPV positive women and 0.9% of screened women, whereas the rate was 0.5% in routine screening. Our findings suggest that self-sampling with HPV mRNA testing is a feasible approach to improve screening efficacy in a high-risk population among original nonattendees.

Clinical Importance of Superior Sensitivity of the Aptima TMA-Based Assays for Mycoplasma genitalium Detection.

Mycoplasma genitalium (MG) is a common cause of nongonococcal cervicitis and urethritis. We investigated the demographic and clinical characteristics of patients tested in Denmark with the Conformité Européenne (CE)/in vitro diagnostics (IVD) Aptima Mycoplasma genitalium assay (CE/IVD AMG; Hologic) and examined the clinical significance of the higher sensitivity of the TMA-based MG assays. From March to June 2016, urogenital and extragenital specimens from consecutive attendees at a sexually transmitted infection clinic in Copenhagen, Denmark were tested with the CE/IVD AMG assay (TMA-based), the research-use-only MG Alt TMA-1 assay (Hologic), a laboratory-developed TaqMan mgpB quantitative real-time PCR (qPCR), and the Aptima Combo 2 (CT/NG; Hologic). Demographic characteristics and clinical symptoms were collected from the patient records. There were 1,245 patients included in the study. The MG prevalence among female subjects was 9.4%, and the MG prevalence among male subjects was 8.7%. Compared to the TMA-based assays, the sensitivity of the PCR-based MG assay was 64.52%, and 55 specimens from 48 individuals were missed in the mgpB qPCR. Of these, 26 individuals (54.2%) were symptomatic, whereas, among 64 individuals with concordant results, 30 individuals (46.9%) were symptomatic; no statistically significant difference was found between the groups (P = 0.567). The improved sensitivity of the TMA-based assays resulted in diagnoses of more patients with clinically relevant symptoms for which antibiotic treatment is indicated. However, approximately half of the MG-infected patients reported no symptoms, and future research is needed to investigate the pros and cons of diagnosing and treating MG in asymptomatic subjects.

Analytical Performance Characteristics of a New Transcription-Mediated Amplification Assay for Treponema pallidum.

This study evaluated the performance characteristics of a new research-use-only transcription-mediated amplification (TMA) assay for the detection of rRNA from Treponema pallidum. Analytical sensitivity determined using dark-field microscopy-quantitated T. pallidum was 1.4 organisms/ml (95% confidence interval [CI], 0.7 to 6.33 organisms/ml). Dilution of in vitro-transcribed (IVT) T. pallidum RNA in Aptima sample transport medium (STM) yielded 100% positivity (n = 3) at 10 copies/ml (4 copies/reaction). Analytical specificity testing of nontarget microorganisms (n = 59), including the closely related nonsyphilis treponemes Treponema denticola and Treponema phagedenis, yielded 0% positivity. TMA testing of mucosal swab specimens collected from men who have sex with men (MSM) attending a sexually transmitted disease clinic yielded 1.8% (17/944) positive results. A collection of 56 serum specimens obtained from a separate cohort of patients with known rapid plasma reagin (RPR) statuses and clinical diagnoses of syphilis was 19.6% (11/56) TMA positive overall and 29.7% (11/37) positive among subjects with syphilis diagnoses, including 8 (36.3%) of 22 persons with primary or secondary syphilis, 2 (20%) of 10 persons with early latent syphilis, and 1 (20%) of 5 persons with late latent or unstaged syphilis. None (0%) of the 18 RPR-positive sera from patients with histories of treated syphilis were TMA positive. These results show that TMA is an analytically sensitive and specific method for the detection of T. pallidum rRNA and is compatible with serum specimens in addition to pharyngeal and rectal mucocutaneous swab specimens. Automated real-time TMA testing for T. pallidum may be useful as an adjunctive method with serology for screening and diagnostic testing of selected patient populations for syphilis.

Performance Evaluation of the BD SARS-CoV-2 Reagents for the BD MAX System.

Nucleic acid amplification testing (NAAT) for SARS-CoV-2 is the standard approach for confirming COVID-19 cases. This study compared results between two emergency use authorization (EUA) NAATs, with two additional EUA NAATs utilized for discrepant testing. The limits of detection (LOD) for the BD SARS-CoV-2 reagents for the BD MAX system (MAX SARS-CoV-2 assay), the bioMérieux BioFire respiratory panel 2.1 (BioFire SARS-CoV-2 assay), the Roche cobas SARS-CoV-2 assay (cobas SARS-CoV-2 assay), and the Hologic Aptima SARS-CoV-2 assay Panther (Aptima SARS-CoV-2 assay) NAAT systems were determined using a total of 84 contrived nasopharyngeal specimens with 7 target levels for each comparator. The positive and negative percent agreement (PPA and NPA, respectively) of the MAX SARS-CoV-2 assay, compared to the Aptima SARS-CoV-2 assay, was evaluated in a postmarket clinical study utilizing 708 nasopharyngeal specimens collected from suspected COVID-19 cases. Discordant testing was achieved using the cobas and BioFire SARS-CoV-2 NAATs. In this study, the measured LOD for the MAX SARS-CoV-2 assay (251 copies/ml; 95% confidence interval [CI], 186 to 427) was comparable to the cobas SARS-CoV-2 assay (298 copies/ml; 95% CI, 225 to 509) and the BioFire SARS-CoV-2 assay (302 copies/ml; 95% CI, 219 to 565); the Aptima SARS-CoV-2 assay had an LOD of 612 copies/ml (95% CI, 474 to 918). The MAX SARS-CoV-2 assay had a PPA of 100% (95% CI, 97.3% to 100.0%) and an NPA of 96.7% (95% CI, 94.9% to 97.9%) compared to the Aptima SARS-CoV-2 assay. The clinical performance of the MAX SARS-CoV-2 assay agreed with another sensitive EUA assay.

Comparison of Aptima and hybrid capture-2 HPV tests and Pap test in the referral population in Japan.

The Aptima human papillomavirus (HPV) test (APTIMA) detects E6-E7 mRNA in abnormal cells in the uterine cervix. To investigate the accuracy of APTIMA for cervical cancer screening in Japan, 423 subjects, mostly referrals with abnormal cytology or being followed up for cervical intraepithelial neoplasia (CIN)1, were screened using two HPV tests, hybrid capture 2 (HC2) and APTIMA, and by the Pap test. Colposcopy was conducted in all subjects with a positive result in either test type. HPV genotyping was performed by Genosearch-31. A result of atypical squamous cells-undetermined significance (ASC-US) or worse on the HC2 test (ASC-US-HC2), and low-grade squamous intraepithelial lesion (LSIL) or worse (LSIL+) on the Pap test, was regarded as positive. APTIMA (97.5%) was more sensitive than LSIL+ (85.1%) for detecting CIN2 or worse (CIN2+) (McNemar test; p = .0003), and more sensitive (98.6%) than ASC-US-HC2 (92.7%) for detecting CIN3+. APTIMA and HC2 had similar sensitivities. HPV genotyping revealed that CIN2/3 with high-risk HPV (HR-HPV) was overlooked in five cases by ASC-US-HC2, and in four cases by HC2, while no such lesions were missed by APTIMA. Thus, APTIMA might be superior to HC2 for primary HPV screening in Japan. One cancer case positive for HPV67 (potentially high risk, [pHR]) was overlooked by Pap test and both HPV tests, suggesting a need for a new HPV test able to detect pHR-HPV types.

Comparative cost analysis of cervical cancer screening programme based on molecular detection of HPV in Spain.

BACKGROUND: HPV cervical cancer screening (CCS) must use validated HPV tests based on the molecular detection of either viral mRNA (Aptima HPV Assay-AHPV) or DNA. AHPV has demonstrated the same cross-sectional and longitudinal sensitivity for the detection of HSIL/CIN2+ lesions but with greater specificity than HPV-DNA tests. The study aimed to estimate the total costs of a CCS with a primary HPV test based on the detection of mRNA compared to DNA in women aged 35-65 years for the National Health System. METHODS: A decision-tree-based model to estimate the cost of the CCS until the first colposcopy was designed based on Spanish CCS guidelines. The total cost (€, 2019) for CCS with AHPV or DNA tests (HC2 and Cobas) was calculated, including HPV test, liquid-based cytology (LBC) and colposcopy, for a population of 7,263,529 women aged 35-65 years (assuming 70% coverage). Clinical inputs derived from a literature review were validated by a multidisciplinary expert panel. Data from head-to-head studies between different HPV tests were selected. RESULTS: The use of AHPV showed reduction of 290,541 (- 35%) and 355,913 (- 40%) LBC compared to HC2 or Cobas, respectively. Furthermore, AHPV avoided 151,699 (- 47%) colposcopies versus HC2 and 151,165 (- 47%) versus Cobas. The total cost of CCS was € 282,747,877 with AHPV, € 322,587,588 with HC2 and € 324,614,490 with Cobas. Therefore, AHPV savings € - 39,839,711 versus HC2 and € - 41,866,613 versus Cobas. CONCLUSIONS: Assuming that 70% of women from 35 to 65 years attend the CCS programme, the cost of screening up to the first colposcopy using AHPV would provide cost savings of up to € 41.9 million versus DNA tests in Spain.

Sensitivity of a transcription-mediated amplification method (Aptima Mycoplasma genitalium assay) to detect M. genitalium in vitro.

INTRODUCTION: Mycoplasma genitalium is a known causative pathogen for some sexually transmitted infections. Nucleic acid amplification tests are a recommended method for detecting M. genitalium. A transcription-mediated amplification (TMA) nucleic acid amplification test to detect M. genitalium, the Aptima Mycoplasma genitalium assay was approved by the Food and Drug Administration in the United States and has been used in other countries. The purpose of this study is to determine the sensitivity of TMA test as the detection limit for 20 strains. METHOD: The sensitivity of the TMA test was re-examined using 20 strains in vitro and the detection limit was estimated by comparison with the MgPa quantitative real-time PCR (qPCR) method. The M. genitalium strains used were isolated from Denmark, Norway, Sweden, France and Japan, and included macrolide or fluoroquinolone resistance. Stock strains were used at several dilutions, with each dilution of each strain examined using both TMA test and qPCR methods. RESULT AND CONCLUSION: Estimated DNA loads of M. genitalium as the detection limit were 0.03-0.87 genome equivalents/mL. Sensitivity for TMA test was almost 100-fold higher than for the qPCR method.

Performance Characteristics of a High-Throughput Automated Transcription-Mediated Amplification Test for SARS-CoV-2 Detection.

The COVID-19 pandemic caused by the new SARS-CoV-2 coronavirus has imposed severe challenges on laboratories in their effort to achieve sufficient diagnostic testing capability for identifying infected individuals. In this study, we report the analytical and clinical performance characteristics of a new, high-throughput, fully automated nucleic acid amplification test system for the detection of SARS-CoV-2. The assay utilizes target capture, transcription-mediated amplification, and acridinium ester-labeled probe chemistry on the automated Panther system to directly amplify and detect two separate target sequences in the open reading frame 1ab (ORF1ab) region of the SARS-CoV-2 RNA genome. The probit 95% limit of detection of the assay was determined to be 0.004 50% tissue culture infective dose (TCID50)/ml using inactivated virus and 25 copies/ml (c/ml) using synthetic in vitro transcript RNA targets. Analytical sensitivity (100% detection) was confirmed to be 83 to 194 c/ml using three commercially available SARS-CoV-2 nucleic acid controls. No cross-reactivity or interference was observed with testing of six related human coronaviruses, as well as 24 other viral, fungal, and bacterial pathogens, at high titers. Clinical nasopharyngeal swab specimen testing (n = 140) showed 100%, 98.7%, and 99.3% positive, negative, and overall agreement, respectively, with a validated reverse transcription-PCR nucleic acid amplification test (NAAT) for SARS-CoV-2 RNA. These results provide validation evidence for a sensitive and specific method for pandemic-scale automated molecular diagnostic testing for SARS-CoV-2.

Characteristics of Mycoplasma genitalium Urogenital Infections in a Diverse Patient Sample from the United States: Results from the Aptima Mycoplasma genitalium Evaluation Study (AMES).

Data from a large prospective multicenter clinical validation study of a nucleic acid amplification in vitro diagnostic test for Mycoplasma genitalium were analyzed to describe the prevalence of M. genitalium infection, risk factors, and disease associations in female and male patients seeking care in diverse geographic regions of the United States. Among 1,737 female and 1,563 male participants, the overall prevalence of M. genitalium infection was 10.3% and was significantly higher in persons ages 15 to 24 years than in persons ages 35 to 39 years (for females, 19.8% versus 4.7% [odds ratio {OR} = 5.05; 95% confidence interval {CI} = 3.01 to 8.46]; for males, 16.5% versus 9.4% [OR = 1.91; 95% CI = 1.20 to 3.02]). The risk for M. genitalium infection was higher in black than in white participants (for females, 12.0% versus 6.8% [OR = 1.88; 95% CI = 1.30 to 2.72]; for males, 12.9% versus 6.9% [OR = 2.02; 95% CI = 1.38 to 2.96]) and higher in non-Hispanic than in Hispanic participants (for females, 11.2% versus 6.0% [OR = 1.97; 95% CI = 1.25 to 3.10]; for males, 11.6% versus 6.8% [OR = 1.80; 95% CI = 1.14 to 2.85]). Participants reporting urogenital symptoms had a significantly elevated risk of M. genitalium infection compared to that for asymptomatic individuals (for females, OR = 1.53 [95% CI = 1.09 to 2.14]; for males, OR = 1.42 [95% CI = 1.02 to 1.99]). Women diagnosed with vaginitis and cervicitis had a higher prevalence of M. genitalium infection than women without those diagnoses, although this was statistically significant only for vaginitis (for vaginitis, OR = 1.88 [95% CI = 1.37 to 2.58]; for cervicitis, OR = 1.42 [95% CI = 0.61 to 2.96]). A diagnosis of urethritis in men was also significantly associated with M. genitalium infection (OR = 2.97; 95% CI = 2.14 to 4.13). Few characteristics distinguished asymptomatic from symptomatic M. genitalium infections. These results from persons seeking care in the United States suggest that M. genitalium infection should be considered in young persons presenting with urogenital symptoms.

Clinical Validation of the Aptima Bacterial Vaginosis and Aptima Candida/Trichomonas Vaginitis Assays: Results from a Prospective Multicenter Clinical Study.

Infectious vaginitis due to bacterial vaginosis (BV), vulvovaginal candidiasis (VVC), and Trichomonas vaginalis accounts for a significant proportion of all gynecologic visits in the United States. A prospective multicenter clinical study was conducted to validate the performance of two new in vitro diagnostic transcription-mediated amplification nucleic acid amplification tests (NAATs) for diagnosis of BV, VVC, and trichomoniasis. Patient- and clinician-collected vaginal-swab samples obtained from women with symptoms of vaginitis were tested with the Aptima BV and Aptima Candida/Trichomonas vaginitis (CV/TV) assays. The results were compared to Nugent (plus Amsel for intermediate Nugent) scores for BV, Candida cultures and DNA sequencing for VVC, and a composite of NAAT and culture for T. vaginalis The prevalences of infection were similar for clinician- and patient-collected samples: 49% for BV, 29% for VVC due to the Candida species group, 4% for VVC due to Candida glabrata, and 10% for T. vaginalis Sensitivity and specificity estimates for the investigational tests in clinician-collected samples were 95.0% and 89.6%, respectively, for BV; 91.7% and 94.9% for the Candida species group; 84.7% and 99.1% for C. glabrata; and 96.5% and 95.1% for T. vaginalis Sensitivities and specificities were similar in patient-collected samples. In a secondary analysis, clinicians' diagnoses, in-clinic assessments, and investigational-assay results were compared to gold standard reference methods. Overall, the investigational assays had higher sensitivity and specificity than clinicians' diagnoses and in-clinic assessments, indicating that the investigational assays were more predictive of infection than traditional diagnostic methods. These results provide clinical-efficacy evidence for two in vitro diagnostic NAATs that can detect the main causes of vaginitis.

Sensitivity, specificity, inclusivity and exclusivity of the updated Aptima Combo 2 assay, which provides detection coverage of the new diagnostic-escape Chlamydia trachomatis variants.

BACKGROUND: Four new variants of Chlamydia trachomatis (nvCTs), detected in several countries, cause false-negative or equivocal results using the Aptima Combo 2 assay (AC2; Hologic). We evaluated the clinical sensitivity and specificity, as well as the analytical inclusivity and exclusivity of the updated AC2 for the detection of CT and Neisseria gonorrhoeae (NG) on the automated Panther system (Hologic). METHODS: We examined 1004 clinical AC2 samples and 225 analytical samples spiked with phenotypically and/or genetically diverse NG and CT strains, and other potentially cross-reacting microbial species. The clinical AC2 samples included CT wild type (WT)-positive (n = 488), all four described AC2 diagnostic-escape nvCTs (n = 170), NG-positive (n = 214), and CT/NG-negative (n = 202) specimens. RESULTS: All nvCT-positive samples (100%) and 486 (99.6%) of the CT WT-positive samples were positive in the updated AC2. All NG-positive, CT/NG-negative, Trichomonas vaginalis (TV)-positive, bacterial vaginosis-positive, and Candida-positive AC2 specimens gave correct results. The clinical sensitivity and specificity of the updated AC2 for CT detection was 99.7 and 100%, respectively, and for NG detection was 100% for both. Examining spiked samples, the analytical inclusivity and exclusivity were 100%, i.e., in clinically relevant concentrations of spiked microbe. CONCLUSIONS: The updated AC2, including two CT targets and one NG target, showed a high sensitivity, specificity, inclusivity and exclusivity for the detection of CT WT, nvCTs, and NG. The updated AC2 on the fully automated Panther system offers a simple, rapid, high-throughput, sensitive, and specific diagnosis of CT and NG, which can easily be combined with detection of Mycoplasma genitalium and TV.

Validation of an Aptima-format Finnish new variant of Chlamydia trachomatis (FI-nvCT) surveillance assay, 2019.

The Finnish new variant of Chlamydia trachomatis (FI-nvCT) is escaping diagnostics in Finland, Norway and Sweden. We have developed and validated an Aptima-format nucleic acid amplification test (NAAT) designed specifically to detect the FI-nvCT. This NAAT has high sensitivity (100%) and specificity (100%) for the FI-nvCT strain, enabling further investigation of the geographic distribution, prevalence and transmission of this diagnostic-escape mutant in screening populations in Europe.

Molecular Testing for Mycoplasma genitalium in the United States: Results from the AMES Prospective Multicenter Clinical Study.

A prospective multicenter clinical study involving subjects from 21 sites across the United States was conducted to validate the performance of a new in vitro diagnostic nucleic acid amplification test (NAAT) for the detection of Mycoplasma genitalium Seven urogenital specimen types (n = 11,556) obtained from 1,778 females, aged 15 to 74 years, and 1,583 males, aged 16 to 82 years, were tested with the Aptima Mycoplasma genitalium assay, an investigational transcription-mediated amplification (TMA) NAAT for the detection of M. genitalium 16S rRNA. Infected status for enrolled subjects was established using results obtained from testing either self-collected vaginal swab or clinician-collected male urethral swab specimens with a composite reference method consisting of three transcription-mediated amplification NAATs targeting unique regions of M. genitalium 16S or 23S rRNA. M. genitalium prevalence was 10.2% in females and 10.6% in males; prevalence was high in both symptomatic and asymptomatic subjects for both sexes. Compared to the subject infected status standard, the investigational test had sensitivity and specificity estimates, respectively, of 98.9% and 98.5% for subject-collected vaginal swabs, 92.0% and 98.0% for clinician-collected vaginal swabs, 81.5% and 98.3% for endocervical swabs, 77.8% and 99.0% for female urine, and 98.2% and 99.6% for male urethral swabs, 88.4% and 97.8% for self-collected penile meatal swabs, and 90.9% and 99.4% for male urine specimens. For all seven specimen types, within-specimen positive and negative agreements between the investigational test and the composite reference standard ranged from 94.2% to 98.3% and from 98.5 to 99.9%, respectively. These results provide clinical efficacy evidence for the first FDA-cleared NAAT for M. genitalium detection in the United States.

Design and Validation of Transcription-Mediated-Amplification Nucleic Acid Amplification Tests for Mycoplasma genitalium.

Mycoplasma genitalium is a sexually transmitted bacterium linked to adverse sexual and reproductive health outcomes in women and men. M. genitalium is difficult to culture, and in the absence of validated amplified molecular methods for diagnosis of infection, there is no reference standard available for use as a comparator for the validation of new M. genitalium diagnostic tests. We evaluated the analytical and clinical performance of three transcription-mediated amplification (TMA) tests for M. genitalium, each targeting unique rRNA sequences, for use as a composite comparator for clinical validation of the Aptima Mycoplasma genitalium (AMG) assay, an in vitro diagnostic (IVD) TMA test that targets 16 s rRNA of M. genitalium Analytical sensitivity, specificity, and strain inclusivity of all four TMA tests were determined using nine laboratory strains of M. genitalium and 56 nontarget bacteria, protozoa, and viruses. Analytical sensitivity of the tests for M. genitalium ranged from 0.017 to 0.040 genome equivalents/ml. None of the nontarget organisms evaluated cross-reacted with any test. A composite comparator reference standard consisting of the 3 alternate (Alt) TMA tests was used to evaluate the clinical performance of the AMG assay by testing residual vaginal swab, female urine, and male urine specimens obtained from 1,400 adult subjects from three U.S. clinical sites. Using this reference standard to establish infected specimen status, the sensitivity, specificity, and overall agreement of the AMG IVD assay were 100%, 99.9%, and 99.9%, respectively. These results demonstrate the utility of molecular composite reference standard methodology for the clinical validation of future IVD tests for this organism.

Longitudinal Clinical Performance of the RNA-Based Aptima Human Papillomavirus (AHPV) Assay in Comparison to the DNA-Based Hybrid Capture 2 HPV Test in Two Consecutive Screening Rounds with a 6-Year Interval in Germany.

Longitudinal data on the E6/E7 mRNA-based Aptima human papillomavirus (AHPV) assay exceeding three years in comparison to the gold standard Digene Hybrid Capture 2 (HC2) test are not available. We previously reported the cross-sectional data of the German AHPV Screening Trial (GAST) in which 10,040 women were recruited and tested by liquid-based cytology, the HC2 assay, and the AHPV assay. Four hundred eleven test-positive women were followed for up to six years. In addition, 3,295 triple-negative women were screened after a median time of six years. Overall, 28 high-grade cervical intraepithelial neoplasia (CIN3) cases were detected. The absolute risk of developing high-risk HPV-positive CIN3+ over six years among those women that tested negative at baseline was 2.2 (95% confidence interval [95% CI], 1.0 to 4.9) and 3.1 (95% CI, 1.7 to 5.7) per 1,000 women screened by the HC2 and the AHPV tests; the additional risk for those with AHPV-negative compared with HC2-negative results was 0.9 (95% CI, -0.2 to 2.1) per 1,000. In comparison, the absolute risk following a negative LBC test was 9.3 (95% CI, 2.9 to 30.2). The relative sensitivity of AHPV compared to HC2 was 91.5% for CIN3+, and the negative predictive values were 99.8% (95% CI, 99.5 to 99.9%) for HC2 and 99.7% (95% CI, 99.4 to 99.8%) for AHPV. Our data show that the longitudinal performance of the AHPV test over six years is comparable to the performance of the HC2 test and that the absolute risk of CIN3+ over six years following a negative AHPV result in a screening population is low. (This study is registered at ClinicalTrials.gov under registration number NCT02634190.).

Aptima Trichomonas vaginalis assay elucidates significant underdiagnosis of trichomoniasis among women in Brazil according to an observational study.

OBJECTIVES: Trichomonas vaginalis (TV) infection is the most common non-viral STI globally and can result in adverse pregnancy outcomes and exacerbated HIV acquisition/transmission. Nucleic acid amplification tests (NAATs) are the most sensitive diagnostic tests, with high specificity, but TV NAATs are rarely used in Brazil. We investigated the TV prevalence and compared the performance of the US Food and Drug Association-cleared Aptima TV assay with microscopy (wet mount and Gram-stained) and culture for TV detection in women in Pelotas, Brazil in an observational study. METHODS: From August 2015 to December 2016, 499 consecutive asymptomatic and symptomatic sexually active women attending a Gynaecology and Obstetrics Outpatient Clinic were enrolled. Vaginal fluid and swab specimens were collected and wet mount microscopy, Gram-stained microscopy, culture and the Aptima TV assay performed. RESULTS: The median age of enrolled women was 36.5 years (range: 15-77). The majority were white, had a steady sexual partner and low levels of education. The TV detection rate was 4.2%, 2.4%, 1.2% and 0% using the Aptima TV assay, culture, wet mount microscopy and Gram-stained microscopy, respectively. The sensitivity of culture and wet mount microscopy was only 57.1% (95% CI 36.5 to 75.5) and 28.6% (95% CI 13.8 to 50.0), respectively. CONCLUSIONS: A 4.2% positivity rate of T. vaginalis was found among women in Pelotas, Brazil and the routine diagnostic test (wet mount microscopy) and culture had low sensitivities. More sensitive diagnostic tests (NAATs) and enhanced testing of symptomatic and asymptomatic at-risk women are crucial to mitigate the transmission of TV infection, TV-associated sequelae and enhanced HIV acquisition and transmission.