Evaluation Of Diagnostic Tests Research Articles

Health-Care Patterns for Three Common Elective Surgeries: Implications for Bundled Payment Models

IntroductionThe study objectives were to assess the timing, duration, and nature of health-care service utilization before and after three common elective surgical procedures not currently included in federal episode-based bundled payment programs. MethodsWe performed a retrospective cohort study of patients undergoing one of three low-risk surgical procedures (breast reduction, upper extremity nerve decompression, and panniculectomy) between 2010 and 2017 using a private insurer’s national claims database. All professional and facility billing claims for health-care services were identified during the 12-mo preoperative and 12-mo postoperative periods for each patient. We compared trends in monthly utilization of health-care services to estimate surgery-related utilization patterns with interrupted time series analyses. ResultsThe cohort included 7885 patients receiving breast reduction, 99,404 patients receiving upper extremity nerve decompression, and 955 patients receiving panniculectomy. The mean monthly encounters gradually increased before each procedure, with a gradual decline in services postoperatively. Claims in the preoperative period for all procedures were primarily diagnostic testing and outpatient evaluation and management. There was limited use of postacute care services across the surgical procedures. There were notable differences in service utilization between the three surgeries, including differing inflection points for preoperative services (approximately 7 mo for breast reduction and panniculectomy, compared with at least 9 mo for nerve decompression) and postoperative services (up to 3 mo for panniculectomy and 4 mo for nerve decompression, compared with 6 mo for breast reduction). ConclusionsThis study highlights important differences in utilization of health-care services by type of surgery. These findings suggest that prior to expanding episode-based bundled payment models to surgical conditions with limited utilization of postacute care services and fewer complications, the Centers for Medicare and Medicaid Services and private payers should consider tailoring the timing and duration of clinical episodes to individual surgical procedures.

Bayesian diagnostic test evaluation and true prevalence estimation of mycoplasma bovis in dairy herds.

The true prevalence of dairy cattle herds with M. bovis infections in the Netherlands is unknown. Previous attempts to estimate prevalences were hampered by the absence of a diagnostic serological test that was validated under field conditions. This study estimated sensitivity and specificity of two commercial serum ELISAs and the true M. bovis herd prevalence using different Bayesian latent class models. A total of 7305 serum samples from 415 randomly chosen dairy herds were collected in fall/winter 2019 and investigated for presence of antibodies against M. bovis using the BIO-K-260 ELISA from Bio-X. Serum samples from 100 of these herds were also tested with a second ELISA, from IDvet. A Bayesian latent class model using the paired test results estimated a sensitivity of 14.1% (95% Bayesian probability interval (BPI): 11.6-16.7%) for the Bio-X ELISA and a specificity of 97.2% (95% BPI: 95.9-98.4%). Sensitivity and specificity for the IDvet ELISA were estimated at 92.5% (95% BPI: 88.3-96.5%) and 99.3% (95% BPI: 98.7-99.8%), respectively. Also, Bio-X ELISA sensitivity was considerably higher with data from calves only and with data from a selection of herds with a clinical outbreak, whereas the IDvet ELISA sensitivity was fairly constant under these conditions. These differences in test sensitivity is expected to be related to an effect of time since infection. A second Bayesian model, applied on test results of all 415 herds, estimated a true herd prevalence of 69.9% (95% BPI: 62.7-77.6%), suggesting M. bovis in endemic amongst dairy cattle herds in the Netherlands. To what extent seropositive herds have experienced a clinical outbreak needs further investigation.

Triaging suspected cancer with a multi-cancer early detection blood test

Notable progress has been made in the field of circulating tumour DNA (ctDNA) analysis over the past decade. Along the spectrum of promising clinical applications of ctDNA across the various stages of cancer, blood-based genotyping in advanced cancer to guide targeted therapies, and more recently, molecular residual disease detection to improve patient selection for adjuvant therapy in stage II colon cancer, are the only indications with sufficient evidence to be integrated into routine clinical care. 1 Pascual J Attard G Bidard FC et al. ESMO recommendations on the use of circulating tumour DNA assays for patients with cancer: a report from the ESMO Precision Medicine Working Group. Ann Oncol. 2022; 33: 750-768 Summary Full Text Full Text PDF PubMed Google Scholar , 2 Tie J Cohen JD Lahouel K et al. Circulating tumor DNA analysis guiding adjuvant therapy in stage II colon cancer. N Engl J Med. 2022; 386: 2261-2272 Crossref PubMed Scopus (137) Google Scholar Among the many other potential applications of ctDNA, a multi-cancer ctDNA test for early detection of multiple cancer types in otherwise healthy individuals, represents the most substantial opportunity to improve cancer survival. Multi-cancer early detection test in symptomatic patients referred for cancer investigation in England and Wales (SYMPLIFY): a large-scale, observational cohort studyThis first large-scale prospective evaluation of an MCED diagnostic test in a symptomatic population demonstrates the feasibility of using an MCED test to assist clinicians with decisions regarding urgency and route of referral from primary care. Our data provide the basis for a prospective, interventional study in patients presenting to primary care with non-specific signs and symptoms. Full-Text PDF Open Access

Multi-cancer early detection test in symptomatic patients referred for cancer investigation in England and Wales (SYMPLIFY): a large-scale, observational cohort study

Analysis of circulating tumour DNA could stratify cancer risk in symptomatic patients. We aimed to evaluate the performance of a methylation-based multicancer early detection (MCED) diagnostic test in symptomatic patients referred from primary care. We did a multicentre, prospective, observational study at National Health Service (NHS) hospital sites in England and Wales. Participants aged 18 or older referred with non-specific symptoms or symptoms potentially due to gynaecological, lung, or upper or lower gastrointestinal cancers were included and gave a blood sample when they attended for urgent investigation. Participants were excluded if they had a history of or had received treatment for an invasive or haematological malignancy diagnosed within the preceding 3 years, were taking cytotoxic or demethylating agents that might interfere with the test, or had participated in another study of a GRAIL MCED test. Patients were followed until diagnostic resolution or up to 9 months. Cell-free DNA was isolated and the MCED test performed blinded to the clinical outcome. MCED predictions were compared with the diagnosis obtained by standard care to establish the primary outcomes of overall positive and negative predictive value, sensitivity, and specificity. Outcomes were assessed in participants with a valid MCED test result and diagnostic resolution. SYMPLIFY is registered with ISRCTN (ISRCTN10226380) and has completed follow-up at all sites. 6238 participants were recruited between July 7 and Nov 30, 2021, across 44 hospital sites. 387 were excluded due to staff being unable to draw blood, sample errors, participant withdrawal, or identification of ineligibility after enrolment. Of 5851 clinically evaluable participants, 376 had no MCED test result and 14 had no information as to final diagnosis, resulting in 5461 included in the final cohort for analysis with an evaluable MCED test result and diagnostic outcome (368 [6·7%] with a cancer diagnosis and 5093 [93·3%] without a cancer diagnosis). The median age of participants was 61·9 years (IQR 53·4-73·0), 3609 (66·1%) were female and 1852 (33·9%) were male. The MCED test detected a cancer signal in 323 cases, in whom 244 cancer was diagnosed, yielding a positive predictive value of 75·5% (95% CI 70·5-80·1), negative predictive value of 97·6% (97·1-98·0), sensitivity of 66·3% (61·2-71·1), and specificity of 98·4% (98·1-98·8). Sensitivity increased with increasing age and cancer stage, from 24·2% (95% CI 16·0-34·1) in stage I to 95·3% (88·5-98·7) in stage IV. For cases in which a cancer signal was detected among patients with cancer, the MCED test's prediction of the site of origin was accurate in 85·2% (95% CI 79·8-89·3) of cases. Sensitivity 80·4% (95% CI 66·1-90·6) and negative predictive value 99·1% (98·2-99·6) were highest for patients with symptoms mandating investigation for upper gastrointestinal cancer. This first large-scale prospective evaluation of an MCED diagnostic test in a symptomatic population demonstrates the feasibility of using an MCED test to assist clinicians with decisions regarding urgency and route of referral from primary care. Our data provide the basis for a prospective, interventional study in patients presenting to primary care with non-specific signs and symptoms. GRAIL Bio UK.

Evaluation of the accuracy of the IDvet serological test for Mycoplasma bovis infection in cattle using latent class analysis of paired serum ELISA and quantitative real-time PCR on tonsillar swabs sampled at slaughter.

Mycoplasma bovis (Mbovis) was first detected in cattle in New Zealand (NZ) in July 2017. To prevent further spread, NZ launched a world-first National Eradication Programme in May 2018. Existing diagnostic tests for Mbovis have been applied in countries where Mbovis is endemic, for detecting infection following outbreaks of clinical disease. Diagnostic test evaluation (DTE) under NZ conditions was thus required to inform the Programme. We used Bayesian Latent Class Analysis on paired serum ELISA (ID Screen Mycoplasma bovis Indirect from IDvet) and tonsillar swabs (qPCR) for DTE in the absence of a gold standard. Tested samples were collected at slaughter between June 2018 and November 2019, from infected herds depopulated by the Programme. A first set of models evaluated the detection of active infection, i.e. the presence of Mbovis in the host. At a modified serology positivity threshold of SP%> = 90, estimates of animal-level ELISA sensitivity was 72.8% (95% credible interval 68.5%-77.4%), respectively 97.7% (95% credible interval 97.3%-98.1%) for specificity, while the qPCR sensitivity was 45.2% (95% credible interval 41.0%-49.8%), respectively 99.6% (95% credible interval 99.4%-99.8%) for specificity. In a second set of models, prior information about ELISA specificity was obtained from the National Beef Cattle Surveillance Programme, a population theoretically free-or very low prevalence-of Mbovis. These analyses aimed to evaluate the accuracy of the ELISA test targeting prior exposure to Mbovis, rather than active infection. The specificity of the ELISA for detecting exposure to Mbovis was 99.9% (95% credible interval 99.7%-100.0%), hence near perfect at the threshold SP%=90. This specificity estimate, considerably higher than in the first set of models, was equivalent to the manufacturer's estimate. The corresponding ELISA sensitivity estimate was 66.0% (95% credible interval 62.7%-70.7%). These results confirm that the IDvet ELISA test is an appropriate tool for determining exposure and infection status of herds, both to delimit and confirm the absence of Mbovis.

An Evaluation of Diagnostic Tests for Aerodigestive Injuries in Penetrating Neck Trauma.

Assessment of aerodigestive injuries in penetrating neck trauma (PNT) is currently left up to the discretion of physicians which can result in a lot of confusion and unnecessary testing. This study was performed at a level 1 trauma center to assess the role of computed tomography arteriogram (CTA) in evaluating for aerodigestive injury in PNT. A total of 242 patients met criteria, with ages ranging from 7 to 86years. Computed tomography arteriogram, EGD, esophagography, and bronchoscopy were classified into positive, negative, and indeterminate results. Computed tomography arteriogram was then further analyzed for violation of the carotid sheath, investing, pretracheal, and deep cervical fascias. Results showed a high sensitivity and NPV (100%) of CTA in assessing aerodigestive injury. Computed tomography arteriogram is a reliable first-line screening tool for aerodigestive injury. EGD appears more useful than esophagography at identifying esophageal injuries. Esophagography and bronchoscopy should be reserved to aid in injury management decision-making rather than as screening studies.

Evaluating the Performance of ChatGPT in Ophthalmology: An Analysis of Its Successes and Shortcomings

Foundation models are a novel type of artificial intelligence algorithms, in which models are pretrained at scale on unannotated data and fine-tuned for a myriad of downstream tasks, such as generating text. This study assessed the accuracy of ChatGPT, a large language model (LLM), in the ophthalmology question-answering space. Evaluation of diagnostic test or technology. ChatGPT is a publicly available LLM. We tested 2 versions of ChatGPT (January 9 "legacy" and ChatGPT Plus) on 2 popular multiple choice question banks commonly used to prepare for the high-stakes Ophthalmic Knowledge Assessment Program (OKAP) examination. We generated two 260-question simulated exams from the Basic and Clinical Science Course (BCSC) Self-Assessment Program and the OphthoQuestions online question bank. We carried out logistic regression to determine the effect of the examination section, cognitive level, and difficulty index on answer accuracy. We also performed a post hoc analysis using Tukey's test to decide if there were meaningful differences between the tested subspecialties. We reported the accuracy of ChatGPT for each examination section in percentage correct by comparing ChatGPT's outputs with the answer key provided by the question banks. We presented logistic regression results with a likelihood ratio (LR) chi-square. We considered differences between examination sections statistically significant at a P value of < 0.05. The legacy model achieved 55.8% accuracy on the BCSC set and 42.7% on the OphthoQuestions set. With ChatGPT Plus, accuracy increased to 59.4% ± 0.6% and 49.2% ± 1.0%, respectively. Accuracy improved with easier questions when controlling for the examination section and cognitive level. Logistic regression analysis of the legacy model showed that the examination section (LR, 27.57; P= 0.006) followed by question difficulty (LR, 24.05; P < 0.001) were most predictive of ChatGPT's answer accuracy. Although the legacy model performed best in general medicine and worst in neuro-ophthalmology (P < 0.001) and ocular pathology (P= 0.029), similar post hoc findings were not seen with ChatGPT Plus, suggesting more consistent results across examination sections. ChatGPT has encouraging performance on a simulated OKAP examination. Specializing LLMs through domain-specific pretraining may be necessary to improve their performance in ophthalmic subspecialties. Proprietary or commercial disclosure may be found after the references.

Efficacy of categorization of urothelial malignancy in atypical urine samples by the Paris system for reporting urinary cytology

Background: Urine cytology is an important screening tool of patients for urothelial carcinoma and follow-up of patients. Ease of procurement, cost-effectiveness, and lower turnaround time are the advantages. Aims and Objectives: The aim of the study was to identify the accuracy of TPS criteria in diagnosing HGUC, considering biopsy as the gold standard and to describe the cytomorphological features in atypical urine specimens and categorization as per reference to TPS of reporting urine cytology. Definition – Atypical urine sample: Urine samples of patients with macroscopic hematuria and other unexplained urinary symptoms, suspicious of urothelial malignancy. Materials and Methods: The study was performed on patients attending urology OPD with macroscopic hematuria and other unexplained urinary symptoms, which were suspicious of urothelial malignancy and whose urine cytology and subsequent biopsy specimens were submitted to the Department of Pathology. Continuous sampling of 56 patients was done. Sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) were used to compare TPS with histopathology. SPSS was used to assess correlation, done by diagnostic test evaluation. Results: Age group of study population ranges from 40 to 84 years with mean age of population as 62 years. Sensitivity, specificity, PPV, and NPV of TPS for reporting urinary cytology in the investigation were 85%, 75%, 65.38%, and 90%. Combination of elevated nuclear-to-cytoplasmic ratio, irregular nuclear border, and hyperchromasia was predictive of malignancy. Conclusion: The criteria outlined by TPS facilitated the standardization of urine cytology reporting and significantly increased the sensitivity of diagnosing HGUC.

Evaluation of laboratory diagnostic tests for light-chain clonality and bone marrow findings in AL amyloidosis.

Light-chain amyloidosis (AL) is the most common form of systemic amyloidosis. This study aimed to evaluate the usefulness of laboratory tests for light-chain clonality and bone marrow (BM) findings in AL amyloidosis. We retrospectively enrolled patients newly diagnosed with AL amyloidosis on pathological examination who underwent a BM biopsy. Laboratory test data for light-chain clonality were collected and compared. Amyloid deposits were identified with H&E, Congo red, and PAS stains. We reviewed 98 patients with AL amyloidosis. Light chain clonality (λ, 64 cases; κ, 34 cases) was detected by serum immunofixation electrophoresis (IFE) (63.3%), urine IFE (70.8%), serum protein electrophoresis (PEP) (44.9%), urine PEP (44.8%), serum free light chain (SFLC) ratio (79.5%), and BM immunohistochemistry (IHC) (85.7%). Flow cytometric (FCM) assay identified aberrant BM plasma cells in 92.9% of cases. BM amyloid deposits were identified in 35 of the 98 cases (35.7%); 71.4% (25/35) were Congo red-positive, and 100.0% (35/35) were PAS-positive. Laboratory tests for detecting light-chain clonality in AL amyloidosis in order of sensitivity include FCM assay for aberrant plasma cells, IHC for light chains on BM biopsy or clot section, SFLC ratio, and serum and urine IFE. Congo red staining of BM samples remains an important tool for identifying amyloid deposits in BM. Periodic acid-Schiff (PAS) staining can be useful in diagnosing some cases of Congo red-negative amyloidosis.

Diagnostic accuracy of an oscillometric blood pressure monitor for atrial fibrillation screening.

Atrial fibrillation is the most common arrhythmia of clinical significance and hypertension is one of its major risk factors. This study aimed to evaluate the diagnostic accuracy of an automated oscillometric blood pressure (BP) monitor with the function of atrial fibrillation detection for atrial fibrillation screening. Patients attending outpatient cardiology clinics were recruited for atrial fibrillation screening by the BP monitor with triplicate BP measurements for atrial fibrillation detection. Furthermore, a single-lead ECG was recorded simultaneously for comparison as the reference standard. The diagnostic test's evaluation index were analyzed, including sensitivity, specificity, and receiver operator characteristic (ROC) analysis. A total of 295 participants were analyzed including 166 males and 129 females, with an average age of 72.5 ± 5.9 years. The sensitivity and specificity for atrial fibrillation detection by the device were 1.000 and 0.904, respectively, with the area under the ROC curve of 0.952 (95% confidence interval: 0.929-0.975, P < 0.001). Furthermore, the device had a Kappa-value of 0.781 ( P < 0.001) with the single-lead ECG in detecting atrial fibrillation. The automated oscillometric BP monitor (G.LAB MD41A0) with atrial fibrillation detection function has high sensitivity and specificity with good accuracy for atrial fibrillation screening, which could be used as a reliable screening tool for the early detection of atrial fibrillation with potential benefits.

Evaluation of a Viable-Cell Detection Assay for Xanthomonas fragariae with Latent Class Analysis

Most molecular diagnostic assays are designed to detect the simple presence of a protein or nucleic acid without regard to whether that protein or nucleic acid originated from a viable and presumably pathogenic organism at the time of isolation. We recently developed a viable-cell detection assay (propidium monoazide [PMA]-qPCR) for specific detection of viable (living) cells of Xanthomonas fragariae, the pathogen causing angular leaf spot of strawberry, and herein describe a unique set of statistical analyses for validation of this assay. For any detection assay or test, calculation of its sensitivity and specificity is essential for determining its diagnostic capabilities, particularly when evaluating competing assays or tests. This is often achieved by running competing tests concurrently on a set of samples with known pathogen density or disease status and cross-tabulating results. However, the PMA-qPCR assay is unique among PCR-based diagnostics because it is designed specifically to detect DNA from living cells only, whereas most traditional PCR assays are designed to detect DNA from the target organism regardless of its state of viability. Thus, one cannot directly compare the results from a cell-viability assay with those from a general assay to gauge the performance of either assay because the assays target two different but overlapping populations (i.e., the viable-cell population and the viable- plus nonviable-cell population). To address this challenge, two standard statistical approaches to diagnostic test evaluation were used jointly to estimate the test performance of the PMA-qPCR assay relative to two common assays for detection of X. fragariae. In both analyses, the PMA-qPCR outperformed the qPCR for detection of viable cells under a range of conditions. Viability testing is extremely useful in certification and disease management applications, and with the information on test performance generated here, the test can be put to practical use to design sampling strategies to account for the errors in testing. [Formula: see text] The author(s) have dedicated the work to the public domain under the Creative Commons CC0 “No Rights Reserved” license by waiving all of his or her rights to the work worldwide under copyright law, including all related and neighboring rights, to the extent allowed by law, 2023.

Evaluation of the Abbott Panbio™ COVID-19 antigen detection rapid diagnostic test among healthcare workers in elderly care.

Coronavirus disease 2019 (COVID-19) has been especially dangerous for elderly people. To reduce the risk of transmission from healthcare workers to elderly people, it is of utmost importance to detect possible severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) positive healthcare workers as early as possible. We aimed to determine whether the Abbott Panbio™ COVID-19 antigen detection rapid diagnostic test (Ag-RDT) could be used as an alternative to reverse transcription-quantitative polymerase chain reaction (RT-qPCR). The second aim was to compare the cycle threshold (Ct) in RT-qPCR with the results of the Ag-RDT. A prospective diagnostic evaluation of the Abbott Panbio™ COVID-19 Ag-RDT among healthcare workers across three elderly care facilities as well as home-based elderly care workers who met clinical criteria for COVID-19 during the second wave of the COVID-19 pandemic. Per healthcare worker, the first nasopharyngeal swab was obtained to perform the Ag-RDT and the second swab for RT-qPCR. A Ct-value of < 40 was interpreted as positive, ≥ 40 as negative. A total of 683 healthcare workers with COVID-19 symptoms were sampled for detection of SARS-CoV-2 by both Ag-RDT and RT-qPCR. Sixty-three healthcare workers (9.2%) tested positive for SARS-CoV-2 by RT-qPCR. The overall sensitivity of Ag-RDT was 81.0% sensitivity (95%CI: 69.6-88.8%) and 100% specificity (95%CI: 99.4-100%). Using a cut-off Ct-value of 32, the sensitivity increased to 92.7% (95% CI: 82.7-97.1%). Negative Ag-RDT results were moderately associated with higher Ct-values (r = 0.62) compared to positive Ag-RDT results. The Panbio™ COVID-19 Ag-RDT can be used to quickly detect positive SARS-CoV-2 healthcare workers. Negative Ag-RDT should be confirmed by RT-qPCR. In case of severe understaffing and with careful consideration, fully vaccinated healthcare workers with Ag-RDT negative results could work with a mask pending PCR results.

Accuracy of Tests for Diagnosis of Animal Tuberculosis: Moving Away from the Golden Calf (and towards Bayesian Models)

The last decades have seen major efforts to develop new and improved tools to maximize our ability to detect tuberculosis-infected animals and advance towards the objective of disease control and ultimately eradication. Nevertheless, there is still uncertainty regarding test performance due to the wide range of specificity and especially sensitivity estimates published in the scientific literature. Here, we performed a systematic review of the literature on studies that evaluated the performance of tuberculosis diagnostic tests used in animals through Bayesian Latent Class Models (BLCMs), which do not require the application of a (fallible) reference procedure to classify animals as infected with tuberculosis or not. BLCM-based sensitivity and specificity estimates deviated from those obtained using a reference procedure for certain antemortem tests: an overall lower sensitivity of skin tests and serology and a higher sensitivity of interferon-gamma (IFN-γ) assays was reported. In the case of postmortem diagnostic tests, sensitivity estimates from BLCMs were similar to estimates from studies based on other methodologies. For specificity, the range of BLCM-based estimates was narrower than those based on a reference test, reaching values close to 100% (but lower in the case of IFN-γ assays). In conclusion, Bayesian methods have been increasingly applied for the evaluation of tuberculosis diagnostic tests in animals, yielding results that differ (sometimes substantially) from previously reported test performance in the literature, particularly for in vivo tests and sensitivity estimates. Newly developed models that allow adjustment for relevant factors (e.g., age, breed, region, and herd size) can contribute to the generation of more unbiased estimates of test performance. Nevertheless, although BLCMs for tuberculosis do not require the use of an imperfect reference procedure and are therefore not influenced by its limited performance, they require careful implementation, and transparent systematic reporting should be the norm.

Modelling the Cost-Effectiveness of Diagnostic Tests.

Diagnostic tests are used to determine whether a disease or condition is present or absent in a patient, who will typically be suspected of having the disease or condition due to symptoms or clinical signs. Economic evaluations of diagnostic tests (e.g. cost-effectiveness analyses) can be used to determine whether a test produces sufficient benefit to justify its cost. Evidence on the benefits conferred by a test is often restricted to its accuracy, which means mathematical models are required to estimate the impact of a test on outcomes that matter to patients and health payers. It is important to realise the case for introducing a new test may not be restricted to its accuracy, but extend to factors such as time to diagnosis and acceptability for patients. These and other considerations may mean the common modelling approach, the decision tree, is inappropriate for underpinning an economic evaluation. There are no consensus guidelines on how economic evaluations of diagnostic tests should be conducted-this article attempts to explore the common challenges encountered in economic evaluations, suggests solutions to those challenges, and identifies some areas where further methodological work may be necessary.

A framework for evaluation of on-farm mastitis diagnostics in Australia.

Numerous culture-based diagnostics are available on the Australian and international markets for on-farm detection of bacterial pathogens in milk. Use of such diagnostics may provide an opportunity to improve the prudent use of antimicrobials in udder health management. Farms are low-resource settings in terms of diagnostic microbiology capacity. The World Health Organisation has identified criteria for the evaluation of diagnostic tests in low resource settings based on Accuracy, Sensitivity, Specificity, User-friendliness, being Rapid or Robust, Equipment-free and being Deliverable (ASSURED). Here, we review how those criteria can be interpreted in the context of microbiological diagnosis of mastitis pathogens, and how on-farm diagnostics that are currently available in Australia perform relative to ASSURED criteria. This evaluation identifies multiple trade-offs, both with regard to scientific criteria and with regards to convenience criteria. More importantly, the purpose of testing may differ between farms, and test performance should be evaluated relative to its intended use. The ability of on-farm mastitis diagnostics to inform mastitis treatment decision-making in a timely and cost-effective manner depends not just on test characteristics but also on farm-specific pathogen prevalence, and on the farm enterprise's priorities and the farm manager's potential courses of action. With most assay evaluations to date conducted in professional laboratories, there is a surprising dearth of information on how well any of the diagnostic tests perform on-farm and, indeed, of the on-farm decision-making processes that they aim to inform.

Evaluation of a rapid diagnostic test for measles IgM detection; accuracy and the reliability of visual reading using sera from the measles surveillance programme in Brazil, 2015.

Laboratory-based case confirmation is an integral part of measles surveillance programmes; however, logistical constraints can delay response. Use of RDTs during initial patient contact could enhance surveillance by real-time case confirmation and accelerating public health response. Here, we evaluate performance of a novel measles IgM RDT and assess accuracy of visual interpretation using a representative collection of 125 sera from the Brazilian measles surveillance programme. RDT results were interpreted visually by a panel of six independent observers, the consensus of three observers and by relative reflectance measurements using an ESEQuant Reader. Compared to the Siemens anti-measles IgM EIA, sensitivity and specificity of the RDT were 94.9% (74/78, 87.4-98.6%) and 95.7% (45/47, 85.5-99.5%) for consensus visual results, and 93.6% (73/78, 85.7-97.9%) and 95.7% (45/47, 85.5-99.5%), for ESEQuant measurement, respectively. Observer agreement, determined by comparison between individuals and visual consensus results, and between individuals and ESEQuant measurements, achieved average kappa scores of 0.97 and 0.93 respectively. The RDT has the sensitivity and specificity required of a field-based test for measles diagnosis, and high kappa scores indicate this can be accomplished accurately by visual interpretation alone. Detailed studies are needed to establish its role within the global measles control programme.

Repeatability of new optical biometer and agreement with 2 validated optical biometers, all based on SS-OCT.

To evaluate the repeatability of the measurements provided by a new optical biometer (EyeStar 900) based on swept-source optical coherence tomography (SS-OCT) and their agreement with the measurements given by 2 validated biometers based on the same technology, the IOLMaster 700 and Argos. IRCCS G.B. Bietti Foundation, Rome, Italy. Prospective evaluation of diagnostic test. In a series of unoperated eyes, 3 consecutive scans were acquired with the EyeStar 900, and 1 with the IOLMaster 700 and the Argos. The following biometry parameters were analyzed: axial length (AL), keratometry (K), corneal astigmatism, central corneal thickness, corneal diameter (CD), anterior chamber depth (ACD), lens thickness (LT), and lens tilting. Repeatability was assessed using test-retest variability, the coefficient of variation (CoV), and the intraclass correlation coefficient (ICC); agreement was based on the 95% limits of agreement. 56 eyes of 56 patients were analyzed. High repeatability was achieved for all measured parameters, as the CoV was <1% in most cases and ICC was >0.95 for all parameters. Good to high agreement was found among the measurements of the 3 optical biometers, although some statistically significant differences were detected between the EyeStar 900 and Argos (mean K, ACD, LT, and CD were higher with the Argos). The Argos measured a shorter AL in eyes >25 mm. The new generation SS-OCT EyeStar 900 optical biometer produces highly repeatable measurements that are in good agreement with those provided by 2 previously validated instruments.

Diagnostic performance of the rapid test for the detection of NS1 antigen and IgM and IgG anti-antibodies against dengue virus.

Motivation for the study: search for accessible and efficient new diagnostic alternatives for the detection of the disease caused by the dengue virus. Main findings: good efficiency of the rapid test during the first days of the disease. As well as its high power to discriminate against other similar mosquito-borne diseases such as Zika and Oropuche. Implications: it could be applied as a screening test in endemic regions that do not have equipment or trained personnel to perform sophisticated and/or complex diagnostic tests. Strengthening public health policies in epidemiological surveillance, early diagnosis and timely treatment. To assess the diagnostic performance of the SD dengue DUO rapid test (Inyecta) for the detection of NS1, IgM and IgG in comparison to the ELISA test. . This is a diagnostic test evaluation that included 286 serum samples from patients with symptomatology attributable to dengue from endemic areas of Peru. The samples were analyzed by ELISA and the SD dengue DUO rapid test (Inyecta) for IgM, NS1 and IgG at the Instituto de Investigación Nutricional in Lima. . The sensitivity of the rapid test was 68.0% for NS1 and IgM, and 86.0% for IgG, improving to 75.0% and 81.0% for NS1 and IgM, respectively, during the first three days. The specificity for all three analytes was greater than 87.0%. The concordance of the results, measured by the Kappa coefficient for the three analytes, was good and no cross-reaction with other arboviruses was found. . The SD dengue DUO rapid test allows detection of NS1, IgM and IgG with adequate sensitivity and specificity. Sensitivity for IgM and NS1 increases when detected during the first three days of symptoms. Therefore, we recommend its implementation in primary care centers for early and timely diagnosis.

Field evaluation of rapid diagnostic tests to determine dengue serostatus in Timor-Leste.

The live attenuated tetravalent CYD-TDV vaccine (Dengvaxia) is effective but has scarcely been used due to safety concerns among seronegative recipients. Rapid diagnostic tests (RDTs) which can accurately determine individual dengue serostatus are needed for use in pre-vaccination screening. This study aimed to determine the performance of existing RDTs (which have been designed to detect levels of immunoglobulin G, IgG, associated with acute post-primary dengue) when repurposed for detection of previous dengue infection (where concentrations of IgG are typically lower). A convenience sample of four-hundred-and-six participants including 217 children were recruited during a community serosurvey. Whole blood was collected by phlebotomy and tested using Bioline Dengue IgG/IgM (Abbott) and Standard Q Dengue IgM/IgG (SD Biosensor) RDTs in the field. Serum samples from the same individuals were also tested at National Health Laboratory. The Panbio indirect IgG ELISA was used as a reference test. Reference testing determined that 370 (91.1%) participants were dengue IgG seropositive. Both assays were highly specific (100.0%) but had low sensitivity (Bioline = 21.1% and Standard Q = 4.6%) when used in the field. Sensitivity was improved when RDTs were used under laboratory conditions, and when assays were allowed to run beyond manufacturer recommendations and read at a delayed time-point, but specificity was reduced. Efforts to develop RDTs with high sensitivity and specificity for prior dengue infection which can be operationalised for pre-vaccination screening are ongoing. Performance of forthcoming candidate assays should be tested under field conditions with blood samples, as well as in the laboratory.

Psychometric Properties and Clinical Utility of the Distress Thermometer in Caregivers of Persons With Multiple Sclerosis.

Caregivers of persons with multiple sclerosis (MS) report high levels of distress. The National Comprehensive Cancer Network Distress Thermometer (DT) is used extensively with patients with cancer and their caregivers but has not been tested in nononcology caregivers. The purpose of this study was to examine the psychometric properties and clinical utility of the barometer portion of the DT in caregivers of persons with MS. A secondary analysis was performed of data from a randomized trial comparing the effectiveness of 2 interventions aimed at reducing psychological outcomes associated with caregiving. The DT and the 4-item Patient-Reported Outcomes Measurement Information System Anxiety and Depression scales, which were administered at baseline, were used for all analyses. Construct validity (known groups) and convergent validity (interscale correlations) were evaluated. Receiver operating characteristic curve analysis was used to evaluate clinical diagnostic test evaluation. The DT had good construct validity supported by strong correlations for known-groups analyses and good convergent validity (r = 0.70-0.72). The DT also demonstrated good discrimination for anxiety (area under the curve [AUC] = 0.83) and depression (AUC = 0.80). The optimal screening cut point on the DT was 4 for anxiety and 5 for depression. The barometer portion of the DT demonstrates good psychometric properties and clinical utility in caregivers of persons with MS. This is the first examination of the DT in MS care partners.