Cross-sectional Diagnostic Accuracy Study Research Articles

Can clinicians identify community-acquired pneumonia on ultralow-dose CT? A diagnostic accuracy study

BackgroundWithout increasing radiation exposure, ultralow-dose computed tomography (CT) of the chest provides improved diagnostic accuracy of radiological pneumonia diagnosis compared to a chest radiograph. Yet, radiologist resources to rapidly report the chest CTs are limited. This study aimed to assess the diagnostic accuracy of emergency clinicians’ assessments of chest ultralow-dose CTs for community-acquired pneumonia using a radiologist’s assessments as reference standard.MethodsThis was a cross-sectional diagnostic accuracy study. Ten emergency department clinicians (five junior clinicians, five consultants) assessed chest ultralow-dose CTs from acutely hospitalised patients suspected of having community-acquired pneumonia. Before assessments, the clinicians attended a focused training course on assessing ultralow-dose CTs for pneumonia. The reference standard was the assessment by an experienced emergency department radiologist. Primary outcome was the presence or absence of pulmonary opacities consistent with community-acquired pneumonia. Sensitivity, specificity, and predictive values were calculated using generalised estimating equations.ResultsAll clinicians assessed 128 ultralow-dose CTs. The prevalence of findings consistent with community-acquired pneumonia was 56%. Seventy-eight percent of the clinicians’ CT assessments matched the reference assessment. Diagnostic accuracy estimates were: sensitivity = 83% (95%CI: 77–88), specificity = 70% (95%CI: 59–81), positive predictive value = 80% (95%CI: 74–84), negative predictive value = 78% (95%CI: 73–82).ConclusionThis study found that clinicians could assess chest ultralow-dose CTs for community-acquired pneumonia with high diagnostic accuracy. A higher level of clinical experience was not associated with better diagnostic accuracy.

Flow cytometric analysis of peripheral blood neutrophil myeloperoxidase expression in myelodysplastic neoplasms (MPO-MDS-Valid): protocol for a multicentre diagnostic accuracy study

IntroductionMany patients referred for suspicion of myelodysplastic neoplasm (MDS) are subjected to unnecessary discomfort from bone marrow aspiration, due to the low disease prevalence in this population. Flow cytometric analysis...

Xpert MTB/RIF Ultra versus mycobacterial growth indicator tube liquid culture for detection of Mycobacterium tuberculosis in symptomatic adults: a diagnostic accuracy study

Xpert MTB/RIF Ultra (Ultra) is an automated molecular test for the detection of Mycobacterium tuberculosis in sputum. We compared the sensitivity of Ultra to that of mycobacterial growth indicator tube (MGIT) liquid culture, considered the most sensitive assay in routine clinical use. In this prospective, multicentre, cross-sectional diagnostic accuracy study, we used a non-inferiority design to assess whether the sensitivity of a single Ultra test was non-inferior to that of a single liquid culture for detection of Mtuberculosis in sputum. We enrolled adults (age ≥18 years) with pulmonary tuberculosis symptoms in 11 countries and each adult provided three sputum specimens with a minimum volume of 2 mL over 2 days. Ultra was done directly on sputum 1, and Ultra and MGIT liquid culture were done on resuspended pellet from sputum 2. Results of MGIT and solid media cultures done on sputum 3 were considered the reference standard. The pre-defined non-inferiority margin was 5·0%. Between Feb 18, 2016, and Dec 4, 2019, we enrolled 2906 participants. 2600 (89%) participants were analysed, including 639 (25%) of 2600 who were positive for tuberculosis by the reference standard. Of the 2357 included in the non-inferiority analysis, 877 (37%) were HIV-positive and 984 (42%) were female. Sensitivity of Ultra performed directly on sputum 1 was non-inferior to that of sputum 2 MGIT culture (MGIT 91·1% vs Ultra 91·9%; difference -0·8 percentage points; 95% CI -2·8 to 1·1). Sensitivity of Ultra performed on sputum 2 pellet was also non-inferior to that of sputum 2 MGIT (MGIT 91·1% vs Ultra 91·9%; difference -0·8 percentage points; -2·7 to 1·0). For the detection of M tuberculosis in sputum from adults with respiratory symptoms, there was no difference in sensitivity of a single Ultra test to that of a single MGIT culture. Highly sensitive, rapid molecular approaches for M tuberculosis detection, combined with advances in genotypic methods for drug resistance detection, have potential to replace culture. US National Institute of Allergy and Infectious Diseases.

Cheeks appearance as a novel predictor of obstructive sleep apnea: the CASA score study.

Four well-established predictors of obstructive sleep apnea (OSA) risk are body mass index, age, sex, and neck circumference. We have previously reported cheeks appearance as an OSA predictor, which may represent a combination of such predictors in a single, readily available feature. This study sought to answer the question: Is cheeks appearance an OSA risk predictor? This was a prospective cross-sectional diagnostic accuracy study based on STARD (standards for reporting diagnostic accuracy studies). Patients undergoing polysomnography to investigate sleep complaints at a sleep clinic affiliated with a university hospital were assessed using cheeks appearance scored 0-3 for volume and 0-3 for flaccidity to create the Cheeks Appearance for Sleep Apnea (CASA) score ranging from 0 to 6. Appearance was judged by 3 blinded and independent evaluators. Among 265 patients evaluated, 248 were included. Fifty-seven patients had a CASA score of 0 and 191 had a CASA score between 1 and 6. Polysomnography diagnosed 177 of the individuals with OSA; of these, 167 had an altered CASA score. Sensitivity was 87%, specificity was 82%, positive-predictive value was 94%, negative-predictive value was 66%, and accuracy was 86%. Our results suggest that combining volume and flaccidity of cheeks appearance in a single index may constitute a reliable OSA predictor. CASA score is a novel predictor of OSA with internal validity in a sleep laboratory adult population. Our findings support further studies to confirm the external validity of this practical diagnostic tool. Registry: ClinicalTrials.gov; Name: Cheeks Appearance as a Novel Predictor of Obstructive Sleep Apnea: The CASA Score Study (CASA); URL: https://clinicaltrials.gov/study/NCT04980586; Identifier: NCT04980586. Prikladnicki A, Gomes E, Sousa LCCR, Gonçalves SC, Martinez D. Cheeks appearance as a novel predictor of obstructive sleep apnea: the CASA score study. J Clin Sleep Med. 2024;20(6):879-885.

Standing on single foot-binding test yields satisfactory results as a novel method for the diagnosis of distal tibiofibular syndesmosis instability: a prospective, cross-sectional diagnostic-accuracy study

BackgroundNon-invasive diagnosis of distal tibiofibular syndesmosis instability (DTSI) was a great challenge to clinicians. We designed a new method, the Standing on single foot-Binding test, and investigated the accuracy of the test in the diagnosis of distal tibiofibular syndesmosis instability in adults with a history of ankle injury.Methods85 participants with ankle injury were subjected to the Standing on single foot-Binding test, MRI and palpation to detect the distal tibiofibular syndesmosis instability (DTSI) and the findings were compared with ankle arthroscopic results. Both participants and arthroscopist were blind to the predicted results of the clinical tests. Sensitivity, specificity, PPV, NPV, LR+, LR − and their 95% CIs were calculated for each of the clinical tests as well as for the positive clinical diagnosis.ResultsThe Standing on single foot-Binding test (SOSF-B test) outperformed MRI and palpation, in terms of sensitivity (87.5%/84.38%), specificity (86.79%/86.79%), PPV (80%/79.41%), NPV (92%/91.2%), LR+ (6.625/6.39), LR- (0.14/0.18) and diagnostic accuracy (87.06/85.88), among others, in the diagnosis of distal tibiofibular syndesmosis instability (DTSI). The diagnostic performance of 20° SOSF-B test was virtually identical to that of 0° SOSF-B test. According to the prevalence (28.7%) of DTSI and LR of four tests, the post-test probability could be used in clinical practice for the prediction of DTSI.ConclusionThis prospective and double-blind diagnostic test showed that the SOSF-B test is clinically feasible for the diagnosis of distal tibiofibular syndesmosis instability (DTSI), and new diagnostic tools for rapid screening of distal tibiofibular syndesmosis instability (DTSI).Level of evidenceII.

Factor structure of the alcohol expectancies questionnaire among adolescents in rural Ghana.

Children's early experiences with alcohol inform the development of alcohol-related beliefs which are known to predict alcohol consumption during the critical stage of adolescence. Yet, there has been considerably less research into these alcohol-related cognitions in low- and middle-income countries (LMIC) and existing measures of these beliefs are highly reflective of Western contexts, which may not be fully appropriate for use in LMICs. The aim is to ascertain the construct validity of the Alcohol Expectancies Questionnaire (AEQ) in a non-Western sample. A cross-sectional diagnostic accuracy study involving 500 adolescents aged 10 to 18 years randomly selected from the database of the Navrongo Health and Demographic Surveillance System. Participants were administered the locally back translated version of the 34-item AEQ. Confirmatory factor analysis using the lavaan package in R was conducted to generate indices for the factor structure of the AEQ. Confirmatory factor analyses showed that while groupings of positive and negative expectancies were similar to those observed when expectancies have been assessed previously in Western studies, these formed a single 'alcohol expectancy' factor. Questions relating to positive tension reduction and negative physical expectancies showed inconsistent responses in this study. Commonly used tools for the assessment of alcohol expectancies may not be suitable for use in Ghana, possibly owing to their development and validation in Western contexts. These findings have implications for the assessment of alcohol-related beliefs in LMIC settings and begin to map out a research agenda to develop more contextually and culturally attune alcohol assessments.

Accuracy of neck circumference in the diagnosis of overweight in children.

The objective of this study was to estimate the accuracy of measuring neck circumference as a diagnostic method for overweight in 10-year-old children. A cross-sectional diagnostic accuracy study was performed in 2019. The population was composed of 942 school children from the municipality of Palhoça, SC, Brazil. For each measurement of the neck circumference, sensitivity, specificity, positive and negative predictive values, likelihood ratio for a positive test, and accuracy were estimated using the receiver operator characteristic curve, with body mass index as a reference. The estimated overall accuracy was 88.9%. For males, the accuracy was 90.1%, and for females, 88.5%. A 30.0 cm neck circumference had a sensitivity of 22.8%, a specificity of 95.4%, a positive predictive value of 76.6%, a negative predictive value of 65.3%, a likelihood ratio for a positive test of 5.0, and an accuracy of 66.7% for all students. Neck circumference showed a global accuracy of 88.9% as a method for diagnosing overweight in 10-year-old children. Predictive values showed high values, mainly starting with a neck circumference of 30 cm.

Technologies for the diagnosis of angle closure glaucoma (ACE): protocol of a prospective, multicentre, cross-sectional diagnostic study

IntroductionAngle-closure is responsible for half of all glaucoma blindness globally. Patients with suspected glaucoma require assessment of the drainage angle by an experienced clinician. The goal of this study is...

Risk assessment of vascular complications following manual therapy and exercise for the cervical region: diagnostic accuracy of the International Federation of Orthopaedic Manipulative Physical Therapists framework (The Go4Safe project).

What is the diagnostic accuracy of the International Federation of Orthopaedic Manipulative Physical Therapists (IFOMPT) framework to assess the risk of vascular complications in patients seeking physiotherapy care for neck pain and/or headache? Cross-sectional diagnostic accuracy study. One hundred and fifty patients seeking physiotherapy for neck pain and/or headache in primary care. Nineteen physiotherapists performed the index test according to the IFOMPT framework. Patients were classified as having a high, intermediate or low risk of vascular complications, following manual therapy and/or exercise, derived from the estimated risk of the presence of vascular pathology. The reference test was a consensus medical decision reached by a vascular neurologist and an interventional neurologist, with input from a neuroradiologist. The neurologists had access to clinical data and magnetic resonance imaging of the cervical spine, including an angiogram of the cervical arteries. Diagnostic accuracy measures were calculated for 'no contraindication' (ie, the low-risk category) and 'contraindication' (ie, the high-risk and intermediate-risk categories) for manual therapy and/or exercise. Sensitivity, specificity, predictive values, likelihood ratios and the area under the curve were calculated. Manual therapy and/or exercise were contraindicated in 54.7% of the patients. The sensitivity of the IFOMPT framework was low (0.50, 95% CI 0.39 to 0.61) and its specificity was moderate (0.63, 95% CI 0.51 to 0.75). The positive and negative likelihood ratios were weak at 1.36 (95% CI 0.93 to 1.99) and 0.79 (95% CI 0.60 to 1.05), respectively. The area under the curve was poor (0.57, 95% CI 0.49 to 0.65). The IFOMPT framework has poor diagnostic accuracy when compared with a reference standard consisting of a consensus medical decision.

In Patients Admitted to a Home Rehabilitation Service, Can a Physical Examination of Muscle, Fat, and Fluid Status be Completed Remotely Via Videocall? A Validation Study.

Teleconsultation via videocall by a dietitian may allow remote diagnosis of malnutrition amongst patients undertaking home rehabilitation; however, whether or not a physical examination can be performed accurately remotely has not yet been determined. This study aimed to compare agreement between an in-person and videocall by a dietitian for overall physical assessment in patients admitted to a home rehabilitation service. This was a cross-sectional diagnostic accuracy study. This study involved 71 adults admitted to the home rehabilitation program at Flinders Medical Centre in Adelaide, South Australia, Australia, between September 2019 to November 2019 and August 2020 to November2020. Validity of the videocall by a dietitian to undertake a physical assessment was determined using an in-person physical assessment completed by a trained dietitian in the participant's own home. A dietitian blinded to the in-person assessment completed the physical examination via a videocall to determine the presence and degree of deficit at each anatomical site and make an overall physical assessment. Percentage agreement, weighted kappa, sensitivity, and specificity were determined to assess agreement between videocall and in-person assessments undertaken by a dietitian. The overall videocall physical examination by a dietitian rating achieved a percentage agreement of 69.0% against the in-person assessment by a dietitian, with a weighted kappa agreement of 0.658 (95% CI 0.530 to 0.786), sensitivity of 87.5%, and specificity of 81.1%. The substantial weighted kappa, good sensitivity, and specificity supports the use of the physical assessment in contributing to diagnosing malnutrition via videocall in home rehabilitation settings. Services that are without a local dietetic workforce should consider using dietitians to undertake videocalls for the physical examination component of nutrition assessment to facilitate timely nutrition assessment and optimal nutrition interventions, as well as support review of nutrition interventions.

A nomogram-based clinical tool for acute ischemic stroke screening in prehospital setting.

Background: We believe that designing a new tool which is comparable in terms of both sensitivity and specificity may play an important role in rapid and more accurate diagnosis of acute ischemic stroke (AIS) in prehospital stage. Therefore, we intended to develop a new clinical tool for the diagnosis of AIS in the prehospital stage. Methods: This was a cross-sectional diagnostic accuracy study. All patients transferred to the emergency department (ED) who underwent brain magnetic resonance imaging (MRI) with impression of AIS were evaluated by 9 clinical tools for stroke diagnosis in the pre-hospital phase including Rapid Arterial Occlusion Evaluation (RACE), Cincinnati Prehospital Stroke Scale (CPSS), Los Angeles Prehospital Stroke Screen (LAPSS), Melbourne Ambulance Stroke Screen (MASS), Medic Prehospital Assessment for Code Stroke (Med PACS), Ontario Prehospital Stroke Screening Tool (OPSS), PreHospital Ambulance Stroke Test (PreHAST), Recognition of Stroke in the Emergency Room (ROSIER), and Face Arm Speech Test (FAST), and totally 19 items were reviewed and recorded. The new clinical tool was developed based on backward method of multivariable logistic regression analysis. The discrimination power of the new clinical tool for diagnosis of AIS was assessed with the area under the receiver operating characteristic curve (AUC-ROC). Results: Data from 806 patients were analyzed; of them, 57.4% were men. The mean age of the study patients was 66.9 years [standard deviation (SD) = 13.9]. In the multivariable model, 8 items remained. The AUC-ROC of the new clinical tool was 0.893 [95% confidence interval (CI): 0.869-0.917], and its best cut-off point was score ≥ 3 for positive AIS. At this cut-off point, sensitivity and specificity were 84.42% and 79.72%, respectively. Conclusion: We introduced a new nomogram-based clinical tool for the diagnosis of AIS in the prehospital stage, which has acceptable specificity and sensitivity; moreover, it is comparable with previous tools.

How good is the diagnostic test accuracy of telehealth assessment for dementia and mild cognitive impairment? A Cochrane Review summary with commentary.

It is estimated that 50% to 80% of people living with dementia worldwide remain undiagnosed and undocumented and have no access to care and treatment. Telehealth services can be utilized as one of the options to improve access to a diagnosis, especially for people living in rural areas or affected by COVID-19 containment measures. To assess the diagnostic accuracy of telehealth assessment for dementia and mild cognitive impairment (MCI). A summary of the Cochrane Review by McCleery et al. 2021, with comments from a rehabilitation perspective. Three cross-sectional diagnostic test accuracy studies (N = 136) were included. Participants were referred from primary care when presenting with cognitive symptoms or were identified as being at high risk of having dementia on a screening test in the care homes. The studies found that telehealth assessment correctly identified 80% to 100% of the people who were diagnosed with dementia during face-to-face assessment and also correctly identified 80% to 100% of people who did not have dementia. Only one study (N = 100) focused on MCI; 71% of participants who had MCI and 73% of participants who did not have MCI were correctly identified via telehealth assessment. Telehealth assessment in this study correctly identified 97% of the participants who had either MCI or dementia, but correctly identified only 22% of those who did not have either. Telehealth assessment for diagnosing dementia seems to have a good level of accuracy when compared to face-to-face assessment, although the small number of studies and small sample sizes and differences between the included studies indicate that the results are uncertain.

Diagnostic accuracy of Cipto Triage Method in the emergency department

Background: The Cipto Triage Method (CTM) is a method developed in Indonesia for assessing the clinical acuity of emergency department patients. To evaluate the accuracy of the CTM, this study compared triage decisions using the CTM performed by nurses to the triage decisions performed by emergency medical officers (EMO). Methods: This cross-sectional diagnostic accuracy study was performed in a single-centre referral hospital in Jakarta, Indonesia. Adult patients who attended the emergency department (ED) met the inclusion criteria. Trauma cases, pregnancy, and psychiatric disorders were excluded. All eligible patients underwent triage assessment based on CTM by a triage nurse and were then referred to the ED treatment zone for triage assessment performed by an EMO. The sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and likelihood ratio were calculated. Results: Between April and July 2022, 902 participants were randomly selected. The overall accuracy of the triage assessment of the index test was 84.7%, and the PPV of resuscitation and urgent triage was very good (90.5% and 84.5%, respectively). In the non-urgent category, the PPV was acceptable (72%), but the NPV was very good (92.2%). Conclusions: Nurse-based triage assessment using CTM in the ED had very good diagnostic accuracy in determining clinical acuity.

Accuracy of airway ultrasound parameters to predict difficult airway using the LEMON criteria as a reference: A cross-sectional diagnostic accuracy study.

Ultrasound (US) airway indexes were frequently compared with other scoring systems such as Mallampati score and Cormack - Lehane classification system, but to the best of our knowledge never with LEMON. Here, in this study, we evaluated the accuracy of some recommended airway US parameters in terms of screening difficult airway using the LEMON criteria as a reference. This was a cross-sectional diagnostic accuracy study in which people with at least 18 years old coming to the emergency departments for any reason who had consent for participation, were enrolled with the simple random sampling method. Hyo-mental distance (HMD), skin to epiglottis distance (EP), and peri-epiglottic space to epiglottis to vocal cord ratio (PEP/E. VC) were the US indexes that were calculated in all participants. Using a preprepared checklist, measured US parameters were recorded. For each participant, the LEMON score variables were also assessed and recorded, and the cutoff point for considering as a difficult airway case, based on LEMON score, was 2. Demographic characteristics of the participants were also registered. A total of 299 cases with a mean age of 41.1 years (95% confidence interval [CI]: 39.3-42.9), were participated. Based on LEMON score ≥2, 20 participants (6.7%) were categorized in difficult airway group. Comparison of the PEP/E. VC (P = 0.007) and EP distance (P = 0.049) of the participants based on LEMON score showed a statistically significant difference; but comparison of the means of HMD in the two groups was not statistically significant (P = 0.144). The median of EP of the participants was 7.70 mm (interquartile range [IQR]: 6.70-9.40). The best cutoff point of EP distance for evaluating a difficult airway was 12.27 mm and more with the sensitivity of 35% and the specificity of 86.96% (accuracy = 0.614; 95% CI: 0.492-0.736). The median of PEP/E. VC was 1.01(IQR: 0.79-1.23). The best cutoff point of PEP/E. VC for evaluating a difficult airway was 0.88 and less with the sensitivity of 70% and the specificity of 67.38% (accuracy = 0.701; 95% CI: 0.583-0.818). As per our results, PEP/E. VC and EP distance measured with sonography can be used in distinguishing the difficult airway, using the LEMON criteria as the reference. However, further studies are needed to use PEP/E. VC and EP distance as a part of reliable indexes.

Validation of non-radiographic APECS software in comparison with standard radiographic measurement of full-length lower limb hip-knee-ankle angle in elderly obese women

IntroductionEvidence suggests that obesity and ageing in women are linked to angular knee abnormalities. The hip-knee-ankle (HKA) angle on a full-limb radiograph is the gold standard measure of lower limb alignment. The AI Posture Evaluation and Correction System (APECS) software is a non-radiographic mobile application designed for whole-body posture assessment. Since exposure to X-ray is associated with harmful effects, there is a need to find a safe and valid alternative for measuring HKA angle. The objective of this research was to determine the validity of the non-radiographic APECS software in comparison with standard radiographic measurement of HKA angle.MethodsThe present cross-sectional diagnostic accuracy study was conducted in a tertiary care hospital of Belagavi, Karnataka, India. Overall, 45 elderly obese females aged 60–80 years with a body mass index of 25 were included. HKA angle was marked bilaterally. Full-limb radiographs were taken and angles were marked with 2.0 version software, DXM model. For the APECS software, full-limb photographs were taken with landmarks indicated with radiant markers and angles were autogenerated by the software.ResultsThe Pearson correlation coefficient between the APECS application and the gold standard (X-ray) was 0.9874 (98.74% of matching). The agreement between standard radiograph and the average of all examiners’ APECS Pro measurements (including right and left sides) equalled 94.64% (kappa = 0.8323; <i>p</i> = 0.001), which suggests very good agreement.ConclusionsThe APECS application demonstrated a high percentage of matching (98.74%) and agreement (94.64%), indicating its excellent validity in measuring HKA angle.

Trial of a Trivial Quantitative Heat-Pain Stimulus for Detecting Severe Loss of Nociception.

Loss of nociception (LON) at the feet of persons with diabetes mellitus develops gradually over years and remains asymptomatic until the first painless diabetic foot ulceration (DFU). Severe LON with pain insensitivity can be diagnosed with a mechanical (pinprick) pain stimulus of 512-mN force. A comparable "suprathreshold" heat-pain stimulus may have the same potential. A six-second, 51°C heat-pain stimulus delivered on a 38.5-mm² spot by a commercial medical device (bite away®, to treat insect bites) was explored in a prospective cross-sectional diagnostic accuracy study to detect DFU-related LON. Seventy-two participants were studied: 12 with and 30 without diabetic neuropathy according to the conventional criteria, and 30 patients with a history of painless DFU (indicative of end-stage LON, reference standard). The feet were stimulated at the plantar and dorsal sides. A palmar surface was stimulated for control purposes. Participants scored stimulated pain intensity 0 to 10 on a numerical rating scale. At hands, pain intensity was rated six on average by all participants. Persons without neuropathy scored 7 (0-10), median (range), at the plantar side and 8.5 (2-10) at the dorsal side of the foot, while those with DFU scored 0 (0-8) and 0 (0-10), respectively. A pain response of 0 at the foot dorsum detected DFU-related LON with a sensitivity of 65% (specificity, 100%; positive and negative predictive values, 100% and 96%, respectively). Due to its high specificity, the test seems advantageous for diagnostic purposes, complementary to current screening tests.

Evaluation of a protein-to-creatinine dipstick diagnostic test for proteinuria screening in selected antenatal care clinics in three Districts in the Bono-East Region of Ghana.

Preeclampsia and eclampsia contribute significantly to maternal and newborn deaths worldwide. Early and accurate identification of pregnant women at risk can avert these deaths, but the necessary diagnostics are not widely available. A protein and creatinine ratio, rather than a measurement of protein alone, may provide better identification of proteinuria. The objective of this study was to assess the operational and performance characteristics of the LifeAssay Diagnostics (LAD) Test-it™ protein-to-creatinine ratio (PrCr) urinalysis dipstick test in a representative antenatal care setting (ANC). Mixed methods were used to assess the operational and performance characteristics of the PrCr test, including a usability study with 25 participants, a prospective cross-sectional diagnostic accuracy study (N=1483), and a targeted reassessment of discordant frozen samples (N=200). Several other commonly used proteinuria tests were included for comparison. The test demonstrated improved clinical performance for detection of proteinuria over the current standard-of-care tests widely used in Ghana. The LAD PrCr test showed a sensitivity of 50.7% and specificity of 69.2% when run at the point of care. In contrast, the standard-of-care Accu-Tell® protein dipstick test was found to have a sensitivity of 32.4% and a specificity of 82.2%. The LAD test shows minor improvement over the tests currently used in Ghana to detect proteinuria. The PrCr test offers the potential for improved detection of proteinuria over the standard-of-care tests used in ANC. However, this test and the others evaluated for this study demonstrate limited performance, particularly among samples with a low level of proteinuria. Additional exploration in other clinical use cases, such as triage among high-risk populations, is warranted. The LAD test can also be considered a transition product, as health systems consider adopting next-generation biomarker tests when more readily available.

Diagnostic accuracy of SARS-CoV-2 rapid antigen self-tests in asymptomatic individuals in the omicron period: a cross-sectional study

ObjectivesTo assess the performances of three commonly used antigen rapid diagnostic tests used as self-tests in asymptomatic individuals in the Omicron period. MethodsWe performed a cross-sectional diagnostic test accuracy study in the Omicron period in three public health service COVID-19 test sites in the Netherlands, including 3600 asymptomatic individuals aged ≥ 16 years presenting for SARS-CoV-2 testing for any reason except confirmatory testing after a positive self-test. Participants were sampled for RT-PCR (reference test) and received one self-test (either Acon Flowflex [Flowflex], MP Biomedicals (MPBio), or Siemens-Healthineers CLINITEST [CLINITEST]) to perform unsupervised at home. Diagnostic accuracies of each self-test were calculated. ResultsOverall sensitivities were 27.5% (95% CI, 21.3–34.3%) for Flowflex, 20.9% (13.9–29.4%) for MPBio, and 25.6% (19.1–33.1%) for CLINITEST. After applying a viral load cut-off (≥5.2 log10 SARS-CoV-2 E-gene copies/mL), sensitivities increased to 48.3% (37.6–59.2%), 37.8% (22.5–55.2%), and 40.0% (29.5–51.2%), respectively. Specificities were >99% for all tests in most analyses. DiscussionThe sensitivities of three commonly used SARS-CoV-2 antigen rapid diagnostic tests when used as self-tests in asymptomatic individuals in the Omicron period were very low. Antigen rapid diagnostic test self-testing in asymptomatic individuals may only detect a minority of infections at that point in time. Repeated self-testing in case of a negative self-test is advocated to improve the diagnostic yield, and individuals should be advised to re-test when symptoms develop.

DIAGNOSTIC ACCURACY COMPARISON OF THE QUANTITATIVE POINT-OF-CARE ECO G6PD AND BREWERS TEST FOR ASSESSMENT OF G6PD DEFICIENCY IN INFECTIOUS DISEASES

Glucose-6-phosphate dehydrogenase (G6PD) deficiency is an X-linked, hereditary condition caused by mutations in the G6PD gene, that results in protein variants with different enzyme activity levels. G6PD provides reducing power to NADPH (reduced form of nicotinamide adenine dinucleotide phosphate). NADPH effect is critical in red blood cells (RBC) due to the absence of a nucleus. Clinical manifestations are usually mild and are induced by an exogenous agent, such as drugs, infections, or dietary (fava beans). The G6PD deficiency diagnosis is crucial in infectious diseases because both infections and treatment can induce acute hemolysis. Rarely, life-threatening cases can require transfusions of RBC and hemodialysis. The gold standard for the measurement of G6PD activity is a quantitative UV spectrophotometric assay, however, it is inaccessible in most cases. Methemoglobin reduction test (Brewer's test) is a qualitative spot test most used for G6PD deficiency screening, but is imprecise, requires a cold chain, some laboratory infrastructure, trained personnel, and is time-costing. Point-of-care (POC) is a simple and fast semi-quantitative test that is becoming increasingly important when a prompt diagnosis is required and in health care of out-of-reach communities. To compare the diagnostic accuracy of the quantitative POC ECO and Brewers test for assessment of G6PD deficiency. A cross-sectional diagnostic accuracy study was enrolled between May 2020 and December 2021 at the Instituto Nacional de Infectologia Evandro Chagas, Fundação Oswaldo Cruz. Individuals older than 17 years old with a suspicious diagnosis of an infectious disease were eligible. 125 convenience blood samples were tested to compare concordance analysis between Brewers test and POC STANDARD G6PD. The exclusion criteria were hemoglobin concentration < 7.0 g/dL due to technical device limitations. A total of 125 subjects (38 females and 87 males) were recruited. The median age was 42.0 years (range 18–76) in females and 45.0 years (range 19–78) in males. The median of G6PD activity was 7.1 U/g Hb (0.2-17.5). We observed a trend of concordance between the G6PD status (deficient or normal), with low frequencies of discordances in the screenings. The strength of agreement between G6PD tests was classified as almost perfect in all participants (k = 0.82, IC95% = 0.66,0.97) and in subgroups female (k = 0.83, IC95% = 0.59,1.00) and male (k = 0.81, IC95% = 0.59,1.00). The total concordance percentage (number of concordances/total) was 95% in females, 97% in males, and 96% in all participants. Here, we demonstrate POC ECO G6PD test could be performed during medical consultation, guiding the most appropriate therapy almost immediately. In addition to saving time and having comparable results to Brewer's test, it could be performed even in remote areas and with scarce resources, dispensing minimum laboratory requirements. Our findings will be of value to diagnose conditions that could have life-threatening consequences if not timely recognized, such as before initiating primaquine for the treatment of malaria. Therefore, it can improve healthcare in vulnerable isolated communities. We observed a high concordance result between Brewers test and POC STANDARD G6PD, which is becoming the reference test to diagnose G6PD deficiency worldwide.

Development of machine learning support for reading whole body diffusion-weighted MRI (WB-MRI) in myeloma for the detection and quantification of the extent of disease before and after treatment (MALIMAR): protocol for a cross-sectional diagnostic test accuracy study

IntroductionWhole-body MRI (WB-MRI) is recommended by the National Institute of Clinical Excellence as the first-line imaging tool for diagnosis of multiple myeloma. Reporting WB-MRI scans requires expertise to interpret and...