Deep mutational scanning identifies SARS-CoV-2 Nucleocapsid escape mutations of currently available rapid antigen tests.

The effects of mutations in continuously emerging variants of SARS-CoV-2 are a major concern for the performance of rapid antigen tests. To evaluate the impact of mutations on 17 antibodies used in 11 commercially available antigen tests with emergency use authorization, we measured antibody binding for all possible Nucleocapsid point mutations using a mammalian surface-display platform and deep mutational scanning. The results provide a complete map of the antibodies' epitopes and their susceptibility to mutational escape. Our data predict no vulnerabilities for detection of mutations found in variants of concern. We confirm this using the commercial tests and sequence-confirmed COVID-19 patient samples. The antibody escape mutational profiles generated here serve as a valuable resource for predicting the performance of rapid antigen tests against past, current, as well as any possible future variants of SARS-CoV-2, establishing the direct clinical and public health utility of our system.

A countrywide survey of hrp2/3 deletions and kelch13 mutation co-occurrence in Ethiopia.

Malaria elimination relies on detection of Plasmodium falciparum Histidine-Rich Proteins 2/3 (HRP2/3) through rapid diagnostic tests (RDTs) and treatment with artemisinin-combination therapies (ACTs). Data from the Horn of Africa suggest increasing hrp2/3 gene deletions and ACT partial resistance kelch13 (k13) mutations. To assess this, 233 samples collected during a national survey from 7 regions of Ethiopia were studied for hrp2/3 deletions by droplet digital dPCR and k13 mutations by DNA sequencing. Approximately 22% of the study population harbored complete hrp2/3 deletions by ddPCR. Thirty-two of 42 of k13 SNPs identified were R622I associated with ACT partial resistance. Both hrp2/3 deletions and k13 mutations associated with ACT partial resistance appear to be co-occurring especially in Northwest Ethiopia. Ongoing national surveillance relying on accurate laboratory methods are required to fully elaborate the genetic diversity of P. falciparum to inform public health policy makers.

Persistence of Detectable Pathogens by Culture-Independent Systems (T2 Magnetic Resonance) in Patients With Bloodstream Infection: Prognostic Role and Possible Clinical Implications.

BACKGROUND: Persistent Staphylococcus aureus bacteremia is associated with metastatic infection and adverse outcomes, whereas gram-negative bacteremia is normally transient and shorter course therapy is increasingly advocated for affected patients. Whether the prolonged detection of pathogen DNA in blood by culture-independent systems could have prognostic value and guide management decisions is unknown. METHODS: We performed a multicenter, prospective, observational study on 102 patients with bloodstream infection (BSI) to compare time to bloodstream clearance according to T2 magnetic resonance and blood cultures over a 4-day follow-up. We also explored the association between duration of detectable pathogens according to T2 magnetic resonance (magnetic resonance-DNAemia [MR-DNAemia]) and clinical outcomes. RESULTS: Time to bloodstream clearance according to T2 magnetic resonance was significantly longer than blood culture clearance (HR, .54; 95% CI, .39-.75) and did not differ according to the causative pathogen (P = .5). Each additional day of MR-DNAemia increased the odds of persistent infection (defined as metastatic infection or delayed source control) both in the overall population (OR, 1.98; 95% CI, 1.45-2.70) and in S. aureus (OR, 1.92; 95% CI, 1.12-3.29) and gram-negative bacteremia (OR, 2.21; 95% CI, 1.35-3.60). MR-DNAemia duration was also associated with no improvement in Sequential Organ Failure Assessment score at day 7 from infection onset (OR, 1.76; 95% CI, 1.21-2.56). CONCLUSIONS: T2 magnetic resonance may help diagnose BSI in patients on antimicrobials with negative blood cultures as well as to identify patients with metastatic infection, source control failure, or adverse short-term outcome. Future studies may inform its usefulness within the setting of antimicrobial stewardship programs.

Rapid Diagnostic Tests and Antimicrobial Stewardship Programs for the Management of Bloodstream Infection: What Is Their Relative Contribution to Improving Clinical Outcomes? A Systematic Review and Network Meta-analysis.

BACKGROUND: Evidence about the clinical impact of rapid diagnostic tests (RDTs) for the diagnosis of bloodstream infections is limited, and whether RDT are superior to conventional blood cultures (BCs) embedded within antimicrobial stewardship programs (ASPs) is unknown. METHODS: We performed network meta-analyses using results from studies of patients with bloodstream infection with the aim of comparing the clinical impact of RDT (applied on positive BC broth or whole blood) to conventional BC, both assessed with and without ASP with respect to mortality, length of stay (LOS), and time to optimal therapy. RESULTS: Eighty-eight papers were selected, including 25 682 patient encounters. There was an appreciable amount of statistical heterogeneity within each meta-analysis. The network meta-analyses showed a significant reduction in mortality associated with the use of RDT + ASP versus BC alone (odds ratio [OR], 0.72; 95% confidence interval [CI], .59-.87) and with the use of RDT + ASP versus BC + ASP (OR, 0.78; 95% CI, .63-.96). No benefit in survival was found associated with the use of RDT alone nor with BC + ASP compared to BC alone. A reduction in LOS was associated with RDT + ASP versus BC alone (OR, 0.91; 95% CI, .84-.98) whereas no difference in LOS was shown between any other groups. A reduced time to optimal therapy was shown when RDT + ASP was compared to BC alone (-29 hours; 95% CI, -35 to -23), BC + ASP (-18 hours; 95% CI, -27 to -10), and to RDT alone (-12 hours; 95% CI, -20 to -3). CONCLUSIONS: The use of RDT + ASP may lead to a survival benefit even when introduced in settings already adopting effective ASP in association with conventional BC.

Double-Negative Results Matter: A Reevaluation of Sensitivities for Detecting SARS-CoV-2 Infection Using Saliva Versus Nasopharyngeal Swabs.

In a recent systematic review, Bastos et al. (Ann Intern Med. 2021;174(4):501-510) compared the sensitivities of saliva sampling and nasopharyngeal swabs in the detection of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection by assuming a composite reference standard defined as positive if either test is positive and negative if both tests are negative (double negative). Even under a perfect specificity assumption, this approach ignores the double-negative results and risks overestimating the sensitivities due to residual misclassification. In this article, we first illustrate the impact of double-negative results in the estimation of the sensitivities in a single study, and then propose a 2-step latent class meta-analysis method for reevaluating both sensitivities using the same published data set as that used in Bastos et al. by properly including the observed double-negative results. We also conduct extensive simulation studies to compare the performance of the proposed method with Bastos et al.'s method for varied levels of prevalence and between-study heterogeneity. The results demonstrate that the sensitivities are overestimated noticeably using Bastos et al.'s method, and the proposed method provides a more accurate evaluation with nearly no bias and close-to-nominal coverage probability. In conclusion, double-negative results can significantly impact the estimated sensitivities when a gold standard is absent, and thus they should be properly incorporated.

Comparison of a dual antibody and antigen HCV immunoassay to standard of care algorithmic testing.

The Centers for Disease Control and Prevention (CDC) guidelines for hepatitis C virus (HCV) testing, although effective, may miss crucial diagnostic opportunities. The goal of this study was to assess the utility of an antibody (Ab) and antigen (Ag) combination immunoassay as an alternative to traditional HCV screening. Remnant specimens from 1,341 patients with concurrent third-generation serologic (Roche anti-HCV-II) and nucleic acid amplification testing (NAAT) were assessed using the HCV Duo Ab/Ag immunoassay (Roche). Patient demographics, risk factors, and standard of care (SOC) laboratory results from the medical records were recorded. Overall, 99.0% (197/199) of the HCV Duo Ab+/Ag+specimens accurately identified active infections as confirmed by NAAT, and 99.9% (670/671) Ab-/Ag- samples corresponded to those without HCV infections. Individually, the HCV Duo Ab component demonstrated a 95.6% positive percent agreement (PPA) (95% CI = 93.8-96.9) and 99.1% negative percent agreement (NPA) (98.8-99.6) compared with SOC anti-HCV II Ab assay. The HCV Duo Ag had a 73.5% PPA (67.9-78.4) and 99.8% NPA (99.3-100) with NAAT. Among RNA+ specimens, 73.4% (197/267) were HCV Duo Ag+, and 265/267 (99.3%) were successfully detected on the HCV Duo Ab component. Notably, 5/7 (71.4%) Ab-/RNA +specimens were detected by HCV Duo, which would have been missed by traditional algorithmic testing. Fourth generation HCV Duo Ab/Ag assay demonstrated comparable performance to SOC testing and shortens the diagnostic window but does not eliminate the need for NAAT in all patients. Ab/Ag testing identified several Ab-/RNA+ cases, a subgroup often undiagnosed by current algorithmic testing, demonstrating promise for improved diagnostic efficiency and accuracy in HCV detection.IMPORTANCEThis study highlights the potential of a combined hepatitis C virus (HCV) Duo antibody (Ab) and antigen (Ag) immunoassay to improve early detection of HCV infections. Traditional Ab-only screening methods recommended by the Centers for Disease Control and Prevention may miss early-stage infections. The HCV Duo assay showed high accuracy, detecting nearly all active infections confirmed by nucleic acid amplification testing. Dual detection of HCV Ab and Ag shortens the diagnostic window, enabling intervention and treatment in a single visit, which is crucial for improving patient outcomes and reducing HCV transmission, especially in areas with limited access to confirmatory molecular testing.

A novel machine-learning aided platform for rapid detection of urine ESBLs and carbapenemases: URECA-LAMP.

Pathogenic gram-negative bacteria frequently carry genes encoding extended-spectrum beta-lactamases (ESBL) and/or carbapenemases. Of great concern are carbapenem resistant Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa, and Acinetobacter baumannii. Despite the need for rapid AMR diagnostics globally, current molecular detection methods often require expensive equipment and trained personnel. Here, we present a novel machine-learning-aided platform for the rapid detection of ESBLs and carbapenemases using Loop-mediated isothermal Amplification (LAMP). The platform consists of (i) an affordable device for sample lysis, LAMP amplification, and visual fluorometric detection; (ii) a LAMP screening panel to detect the most common ESBL and carbapenemase genes; and (iii) a smartphone application for automated interpretation of results. Validation studies on clinical isolates and urine samples demonstrated percent positive and negative agreements above 95% for all targets. Accuracy, precision, and recall values of the machine learning model deployed in the smartphone application were all above 92%. Providing a simplified workflow, minimal operation training, and results in less than an hour, this study demonstrated the platform's feasibility for near-patient testing in resource-limited settings.IMPORTANCEExtended-spectrum beta-lactamases (ESBL) and carbapenemases confer resistance to third-generation cephalosporins and carbapenems in pathogenic Gram-negative bacteria such as Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa, and Acinetobacter baumannii. Conventional antimicrobial susceptibility testing is based on phenotypic methods, and results can take several days to be obtained. Current genotypic detection methods can be rapid but require expensive equipment and trained personnel. In this study, we present a novel machine learning-aided platform for the rapid detection of ESBLs and carbapenemases using Loop-mediated isothermal Amplification (LAMP). The validation of the platform demonstrated percent positive and negative agreements above 95% for all targets. The newly developed platform provided a simplified workflow, minimal technical training, and results in less than an hour. This study demonstrated the platform's feasibility for rapid testing of ESBL and carbapenemases in bacteria and urine specimens.

Screening for hepatitis C virus at the time of mammography using rapid diagnostic tests in women aged between 50 and 74 years (Mamm'OC NCT05067374).

Chronic hepatitis C Virus (HCV) infection presents a global health challenge, with significant morbidity and mortality worldwide. Despite remarkable progress in treatment options, achieving elimination targets by 2030, as set by the World Health Organization, remains elusive. Our study aimed to address this gap by integrating HCV screening into a national breast cancer screening program. Between March 2022 and March 2023, a prospective cross-sectional multicenter study was conducted in four radiology centers in Montpellier, France. We proposed HCV screening to consecutive women undergoing mammography, targeting 1,500 participants aged 50-74 years. A rapid diagnostic test (RDT) for HCV antibodies (HCV Ab) was performed on capillary whole blood, with positive cases undergoing serological and RNA confirmation. Participants also completed a questionnaire on demographic data and risk factors. Acceptance rates, HCV prevalence, and linkage to care were assessed. The acceptance rate for this integrated screening approach was 82.4%. Notably, the seroprevalence of HCV was found to be 0.65%. Linkage to care was prompt, and the cascade of care demonstrated successful treatment outcomes. Importantly, the majority of detected infections were successfully resolved. These findings underscore the feasibility and acceptability of integrating HCV screening with breast cancer screening programs providing updated prevalence data and valuable insights for refining future screening strategies.

A novel test and treat program for hepatitis C virus infection utilizing HCV core antigen testing, among police and general population, Islamabad, Pakistan, 2022.

Hepatitis C virus core antigen (HCVcAg) testing can simplify and decrease costs of HCV infection confirmation compared to molecular testing (nucleic acid testing). We piloted HCVcAg testing for the confirmation of active infection. The study was conducted during June through December 2022 among the police and the general population of Islamabad, Pakistan age 18 years and older. Initial screening for HCV antibody was conducted using a rapid diagnostic test (RDT) for all consenting participants. Those who tested positive had venous blood samples tested for HCVcAg, platelets and aspartate aminotransferase (AST). Persons with HCVcAg values ≥3 fmol/L were defined as viremic, and they were offered treatment with direct acting antiviral (DAA) medications, sofosbuvir and daclatasvir. Aspartate aminotransferase to platelet ratio index (APRI) was calculated for each HCV infected person, and those with an APRI score <1.5 received treatment for 12 weeks, while those with APRI ≥ to 1.5 received 24 weeks of treatment. A total of 15,628 persons were screened for anti-HCV using RDT and 643 (4.1%) tested positive. HCVcAg values of ≥3 fmol/L was found in 399/643 (62.1%), and all were offered and accepted treatment. Of those treated, 273/399 (68.4%) returned for a follow-up SVR and HCVcAg was not detected in 261/273, a 95.6% cure rate. The pilot study demonstrated the effectiveness of reaching and treating an urban population using RDT for screening and HCVcAg for confirmation of infection and test of cure.

Biomarkers and Diagnostic Thresholds for Congenital Hyperinsulinism.

CONTEXT: Congenital Hyperinsulinism (CHI) is associated with inappropriately high levels of C-peptide in the context of hypoglycemia. OBJECTIVE: We aimed to better clarify a diagnostic threshold value of C-peptide for children presenting with CHI. DESIGN: This was a retrospective case-control analysis, examining all hypoglycemia screens, undertaken between 2009 and 2019 at a quaternary paediatrics unit. Plasma C-peptide, insulin, free fatty acid (FFA) and B-hydroxybutyrate (BHOB) concentrations in children diagnosed with CHI were compared with concentrations in children diagnosed with other conditions. PATIENTS: All patients requiring hypoglycaemic screens at the quaternary children's hospital were analysed. RESULTS: Median [C-peptide] were statistically significantly different between CHI (147) and non-CHI (72) patients, p < 0.05. The Youden Index indicated that a [C-peptide] value of 291.5 pmol/L would give the greatest optimization of sensitivity (82%) and specificity (99%) for detecting CHI. Median [insulin] differed significantly between the cohorts with a level of 64 pmol/L for CHI patients compared with 0 pmol/L with non-CHI patients (p < 0.01). Median [BOHB] was 0 µmol/L in CHI patients as compared with 2378 µmol/L for non-CHI patients (p < 0.01). Median [FFA] levels were 1910 µmol/L in the non-CHI cohort, compared with 0 in the CHI cohort (p < 0.01). CONCLUSIONS: This study suggests that a C-peptide concentration greater than 291.5 pmol/L is diagnostic of CHI in children. C-peptide appears to offer the greatest utility as a biochemical diagnostic test for CHI and could be prioritised for laboratory analysis.

Systematic review and meta-analyses on the accuracy of diagnostic tests for IgE-mediated food allergy.

The European Academy of Allergy and Clinical Immunology (EAACI) is updating the Guidelines on Food Allergy Diagnosis. We aimed to undertake a systematic review of the literature with meta-analyses to assess the accuracy of diagnostic tests for IgE-mediated food allergy. We searched three databases (Cochrane CENTRAL (Trials), MEDLINE (OVID) and Embase (OVID)) for diagnostic test accuracy studies published between 1 October 2012 and 30 June 2021 according to a previously published protocol (CRD42021259186). We independently screened abstracts, extracted data from full texts and assessed risk of bias with QUADRAS 2 tool in duplicate. Meta-analyses were undertaken for food-test combinations for which three or more studies were available. A total of 149 studies comprising 24,489 patients met the inclusion criteria and they were generally heterogeneous. 60.4% of studies were in children ≤12 years of age, 54.3% were undertaken in Europe, ≥95% were conducted in a specialized paediatric or allergy clinical setting and all included oral food challenge in at least a percentage of enrolled patients, in 21.5% double-blind placebo-controlled food challenges. Skin prick test (SPT) with fresh cow's milk and raw egg had high sensitivity (90% and 94%) for milk and cooked egg allergies. Specific IgE (sIgE) to individual components had high specificity: Ara h 2-sIgE had 92%, Cor a 14-sIgE 95%, Ana o 3-sIgE 94%, casein-sIgE 93%, ovomucoid-sIgE 92/91% for the diagnosis of peanut, hazelnut, cashew, cow's milk and raw/cooked egg allergies, respectively. The basophil activation test (BAT) was highly specific for the diagnosis of peanut (90%) and sesame (93%) allergies. In conclusion, SPT and specific IgE to extracts had high sensitivity whereas specific IgE to components and BAT had high specificity to support the diagnosis of individual food allergies.

Nonparametric receiver operating characteristic curve analysis with an imperfect gold standard.

This article addresses the challenge of estimating receiver operating characteristic (ROC) curves and the areas under these curves (AUC) in the context of an imperfect gold standard, a common issue in diagnostic accuracy studies. We delve into the nonparametric identification and estimation of ROC curves and AUCs when the reference standard for disease status is prone to error. Our approach hinges on the known or estimable accuracy of this imperfect reference standard and the conditional independent assumption, under which we demonstrate the identifiability of ROC curves and propose a nonparametric estimation method. In cases where the accuracy of the imperfect reference standard remains unknown, we establish that while ROC curves are unidentifiable, the sign of the difference between two AUCs is identifiable. This insight leads us to develop a hypothesis-testing method for assessing the relative superiority of AUCs. Compared to the existing methods, the proposed methods are nonparametric so that they do not rely on the parametric model assumptions. In addition, they are applicable to both the ROC/AUC analysis of continuous biomarkers and the AUC analysis of ordinal biomarkers. Our theoretical results and simulation studies validate the proposed methods, which we further illustrate through application in two real-world diagnostic studies.

Receipt of antimalarials among children aged 6-59 months in Nigeria from 2010 to 2021.

BACKGROUND: Nigeria has the highest malaria burden globally, and anti-malarials have been commonly used to treat malaria without parasitological confirmation. In 2012, Nigeria implemented rapid diagnostic tests (RDTs) to reduce the use of anti-malarials for those without malaria and to increase the use of artemisinin-based combination therapy (ACT) for malaria treatment. This study examined changes in anti-malarial receipt among children aged 6-59 months during a 12-year period of increasing RDT availability. METHODS: A cross-sectional analysis was conducted using the Nigeria Malaria Indicator Survey (NMIS) data from 2010 (before RDT implementation in 2012), 2015, and 2021. The analysis assessed trends in prevalence of malaria by survey RDT result, and fever and anti-malarial/ACT receipt in the 2 weeks prior to the survey. A multivariable logistic regression was used to account for the complex survey design and to examine factors associated with anti-malarial receipt, stratified by survey RDT result, a proxy for recent/current malaria infection. RESULTS: In a nationally-representative, weighted sample of 22,802 children aged 6-59 months, fever prevalence remained stable over time, while confirmed malaria prevalence decreased from 51.2% in 2010 to 44.3% in 2015 and 38.5% in 2021 (trend test p < 0.0001). Anti-malarial use among these children decreased from 19% in 2010 to 10% in 2021 (trend test p < 0.0001), accompanied by an increase in ACT use (2% in 2010 to 8% in 2021; trend test p < 0.0001). Overall, among children who had experienced fever, 30.6% of survey RDT-positive and 36.1% of survey RDT-negative children had received anti-malarials. The proportion of anti-malarials obtained from the private sector increased from 61.8% in 2010 to 80.1% in 2021 for RDT-positive children; most of the anti-malarials received in 2021 were artemisinin-based combinations. Factors associated with anti-malarial receipt for both RDT-positive and RDT-negative children included geographic region, greater household wealth, higher maternal education, and older children. CONCLUSION: From 2010 to 2021 in Nigeria, both malaria prevalence and anti-malarial treatments among children aged 6-59 months decreased, as RDT availability increased. Among children who had fever in the prior 2 weeks, anti-malarial receipt was similar between children with either positive or negative survey RDT results, indicative of persistent challenges in reducing inappropriate anti-malarials uptake.

Limited threat of Plasmodium falciparum pfhrp2 and pfhrp3 gene deletion to the utility of HRP2-based malaria RDTs in Northern Uganda.

BACKGROUND: Rapid diagnostic tests (RDTs) that detect Plasmodium falciparum histidine-rich protein-2 (PfHRP2) are exclusively deployed in Uganda, but deletion of the pfhrp2/3 target gene threatens their usefulness as malaria diagnosis and surveillance tools. METHODS: A cross-sectional survey was conducted at 40 sites across four regions of Uganda in Acholi, Lango, W. Nile and Karamoja from March 2021 to June 2023. Symptomatic malaria suspected patients were recruited and screened with both HRP2 and pan lactate dehydrogenase (pLDH) detecting RDTs. Dried blood spots (DBS) were collected from all patients and a random subset were used for genomic analysis to confirm parasite species and pfhrp2 and pfhrp3 gene status. Plasmodium species was determined using a conventional multiplex PCR while pfhrp2 and pfhrp3 gene deletions were determined using a real-time multiplex qPCR. Expression of the HRP2 protein antigen in a subset of samples was further assessed using a ELISA. RESULTS: Out of 2435 symptomatic patients tested for malaria, 1504 (61.8%) were positive on pLDH RDT. Overall, qPCR confirmed single pfhrp2 gene deletion in 1 out of 416 (0.2%) randomly selected samples that were confirmed of P. falciparum mono-infections. CONCLUSION: These findings show limited threat of pfhrp2/3 gene deletions in the survey areas suggesting that HRP2 RDTs are still useful diagnostic tools for surveillance and diagnosis of P. falciparum malaria infections in symptomatic patients in this setting. Periodic genomic surveillance is warranted to monitor the frequency and trend of gene deletions and its effect on RDTs.

Where Do Plasma Biomarkers fit in With Current Alzheimer's Disease Detection?

OBJECTIVES: We examine the clinical utility of plasma-based detection for Alzheimer's disease (AD) pathophysiology in older adults with mild cognitive impairment (MCI) and whether cognitive screening can inform when to use plasma-based AD tests. METHODS: Seventy-four community-dwelling older adults with MCI had testing with plasma phosphorylated tau (p-tau) 217 and 181, positron emission tomography (PET) imaging for amyloid beta (Aß), and cognitive assessment. Receiver operating characteristic (ROC) analysis was used to assess the diagnostic value of plasma p-tau. RESULTS: Plasma p-tau217 distinguished MCI participants who had PET imaging evidence of Aß accumulation from those without (AUC of 0.92, specificity of 0.96, and sensitivity of 0.90), outperforming plasma p-tau181 (AUC of 0.76, specificity of 0.87 and sensitivity of 0.59) for the same purpose. Of the 60 MCI participants that were amnestic, 22 were Aß+. The 14 participants that were nonamnestic were all Aß-. CONCLUSIONS: Our findings support the clinical use of plasma p-tau, particularly p-tau217, for patient detection of AD pathophysiology in older adults with amnestic MCI, but not in those who are nonamnestic.

Extending the DeLong algorithm for comparing areas under correlated receiver operating characteristic curves with missing data.

A nonparametric method proposed by DeLong et al in 1988 for comparing areas under correlated receiver operating characteristic curves is used widely in practice. However, the DeLong method as implemented in popular software quietly deletes individuals with any missing values, yielding potentially invalid and/or inefficient results. We simplify the DeLong algorithm using ranks and extend it to accommodate missing data by using a mixed model approach for multivariate data. Simulation results demonstrate the validity and efficiency of our procedure for data missing at random. We illustrate our proposed procedure in SAS, Stata, and R using the original DeLong data.

Concordance between radioimmunoassay and fixed cell-based assay in subjects without myasthenia gravis: optimizing the diagnostic approach.

BACKGROUND AND PURPOSE: Acetylcholine receptor antibody (AChR-Ab) detection is crucial in myasthenia gravis (MG) diagnosis and, currently, the radioimmunoassay (RIA) is the gold standard. However, RIA may detect AChR-Ab against nonpathogenic intracellular epitopes. In this study, we performed fixed cell-based assay (F-CBA) in RIA-AChR-Ab positive subjects without MG symptoms, to assess whether F-CBA could show a higher specificity compared to RIA in detecting pathogenic Abs. METHODS: We reviewed medical records of patients referred to our MG outpatient clinic because of RIA-AChR-Ab detection. MG diagnosis was based on clinical examination, electrophysiology and Ab detection. AChR-Abs were tested by RIA in the whole cohort. Serum samples from RIA-positive asymptomatic subjects were retested by F-CBA. RESULTS: Of 605 subjects who tested RIA-AChR-Ab positive, MG diagnosis was confirmed in 599. Six subjects were RIA-AChR-Ab positive although they had never had MG symptoms; in four of these subjects AChR-Abs were not detected by F-CBA, whereas the remaining two (both non-MG thymoma cases) were positive also by F-CBA. CONCLUSIONS: RIA false positivity for AChR-Ab is very rare. Previous literature has demonstrated that F-CBA has higher sensitivity than RIA for MG, especially in ocular cases. Our preliminary results show that, in rare instances, F-CBA may be more specific than RIA for MG diagnosis.

External quality assessment to support the WHO ProSPeRo study for the evaluation of two dual HIV/syphilis point-of-care tests in seven countries.

BACKGROUND: Sexually transmitted infections (STIs) such as syphilis and HIV remain to be a significant public health issue worldwide. Dual rapid point-of-care tests (POCTs) have shown promise for detecting antibodies to HIV and syphilis but have not been fully evaluated in the field. Our study supported the WHO ProSPeRo study on Sexually Transmitted Infection Point-of-Care Testing (STI POCT) by providing external quality assessment (EQA) for HIV and syphilis testing in reference laboratories and their associated clinical sites in seven countries. METHODS: HIV/syphilis serum liquid and dried tube specimen (DTS) panels were prepared by CDC. Liquid panels were distributed to the reference laboratories for three rounds of testing using commercially and locally available laboratory-based serological tests. DTS panels were sent to the clinical testing sites for 8 rounds of POC testing using the Abbott SD BIOLINE HIV/Syphilis Duo test (hereafter referred to as SD BIOLINE) and the Chembio Dual Path Platform (DPP) HIV-Syphilis assay. EQA panels were tested at CDC using the Rapid Plasma Reagin (RPR) test and the Treponema pallidum Particle Agglutination assay (TP-PA) for syphilis antibodies. Genetic Systems HIV-1/HIV-2 Plus O EIA, Geenius HIV Supplemental Assay and the Oraquick Advance HIV test were used to detect HIV antibodies in the EQA panels. Results from the reference laboratories and POCT sites were compared to those obtained at the CDC and a percentage agreement was calculated. RESULTS: Qualitative RPR and TP-PA performed at the reference laboratories demonstrated 95.4-100% agreement with CDC results while quantitative RPR and TP-PA tests demonstrated 87.7% and 89.2% agreement, respectively. A 93.8% concordance rate was observed for qualitative HIV testing in laboratories. EQA testing at clinical sites using dual tests showed 98.7% and 99.1% agreement for detection of HIV antibodies and eight out of 10 sites had > 95.8% agreement for syphilis testing. However, two clinical sites showed only 65.0-66.7% agreement for SD BIOLINE and 84.0-86.7% for DPP, respectively, for syphilis testing. CONCLUSIONS: Overall, laboratories demonstrated high EQA performance in this study. Both HIV/syphilis POCTs gave expected results in the clinic-based evaluations using DTS. However, testing errors were identified in a few testing sites suggesting the necessity for continuous training and monitoring the quality of POC testing.

Age group-specific changes in keratinocyte cancer treatment rates in Australia, 2012-2021: a retrospective cohort study based on MBS claims data.

OBJECTIVES: To examine recent changes in the numbers of Medicare-subsidised keratinocyte cancer excisions, particularly for younger people exposed to primary prevention campaigns since the early 1980s. STUDY DESIGN: Retrospective cohort study; analysis of administrative data. SETTING, PARTICIPANTS: Analysis of Medicare Benefits Schedule (MBS) claims data for procedures related to the diagnosis and treatment of keratinocyte cancer in Australia, 2012-2021. MAIN OUTCOME MEASURES: Age-standardised rates for MBS-subsidised claims for first surgical squamous cell carcinoma (SCC) and basal cell carcinoma (BCC) excisions, Mohs surgery, surgical excisions of benign lesions, skin biopsies, and cryotherapy or serial curettage of premalignant and malignant lesions, overall, and by sex, state/territory, and age group; average annual percentage change in rate for time intervals determined by joinpoint regression. RESULTS: In men, the age-standardised rate of BCC/SCC excisions increased by 1.9% (95% confidence interval [CI], 1.4-2.4%) per year during 2012-2019 (from 2931 to 3371 per 100 000 men) and then declined by 3.8% (95% CI, 0.5-7.0%) per year during 2019-2021 (to 3152 per 100 000). In women, the age-standardised rate increased by 2.2% (95% CI, 1.7-2.8%) per year during 2012-2019 (from 1798 to 2093 per 100 000 women); the decline to 1967 excisions per 100 000 women in 2021 was not statistically significant. BCC/SCC excision rates declined for men under 55 years of age (by 1.0-3.4% per year) and women under 45 years of age (by 1.7-2.3% per year). Age-standardised biopsy rates increased during 2012-2021 in all age groups (by 2.8-6.9% per year). CONCLUSIONS: Rates of MBS-subsidised treatment for keratinocyte cancers increased during 2012-2019, but BCC/SCC treatment rates declined among younger Australians, who have probably been exposed to less sunlight than earlier generations because of public health interventions and population-wide lifestyle changes related to technology use.

ABPA and AFRS: addressing prevalence, early diagnosis, allergens, and occupational concerns.

OBJECTIVE: This study aimed to comprehensively investigate the prevalence of ABPA and AFRS, scrutinize existing diagnostic criteria and immunoassays, pinpoint their limitations, highlight ABPA as an occupational health implication, and identify suggestive measures to improve ABPA diagnosis in the context of Occupational Health Nursing and primary healthcare. DATA SOURCES: The data sources such as PubMed, Health and Safety Science Abstracts, OSH Update, Medline, and Google Scholar were searched. STUDY SELECTIONS: All published studies in the English language from 1990 till Oct, 2023 using Mesh terms keywords "Allergic bronchopulmonary aspergillosis," "Allergic fungal rhinosinusitis," "Signs and Symptoms," "Rapid Diagnostic Tests," "Diagnosis," "Occupational Health," "Occupational Health Nursing," "Prevalence," "Allergens" following "Boolean operators" search strategy were selected. RESULTS: This review succinctly covered signs, symptoms, and prevalence data concerning ABPA and AFRS. It briefly discussed existing diagnostic criteria and immunoassays, highlighted factors influencing the assay's variability, and underscored the role and scope of specific allergens toward improved, simple, and early ABPA diagnosis. ABPA as a neglected occupational health concern was emphasized, and the importance of RDTs in the context of healthcare professionals and OHNs was stated. Finally, this study suggested analyzing the impact of compromised post-pandemic immune status and the use of immunosuppressive drugs on ABPA prevalence among vulnerable communities and occupations. CONCLUSION: To conclude, global and Indian ABPA and AFRS prevalence data, factors influencing existing assay variability, and the scope of improvement in RDTs for ABPA diagnosis in the background of primary healthcare professionals and OHNs were addressed.