Similar Diagnostic Sensitivity Research Articles

How excellent can centres of excellence be? The impact of prevalence on service quality.

Centres of Excellence (CEs) are thought to provide better quality services for their speciality than Generic Services (GS). However, clinical test theory suggests this may arise from differences in the prevalence of these specialities' conditions in their referral populations, which affects the services' ability to detect diagnoses accurately, even with similar diagnostic sensitivities and specificities. Furthermore, GS' insensitivity to rarer diagnoses is necessary to avoid serious overdiagnosis despite using skills equivalent to CEs. Good GS can perform as well as CEs for disorders of 15% to 20% or greater prevalence in their referral populations, depending on the Minimal Clinically Important Difference (MCID) decided for their diagnoses' positive predictive values or degree of bias. CEs are necessary for rare disorders and have a role in determining MCIDs and the sensitivity and specificity of new measures. Sensitivity, specificity, positive & negative predictive values, and true diagnostic prevalence should be routine outcome measures.

Psychometric properties of the GAD-7 and PROMIS-Anxiety-4a among youth with depression and suicidality: Results from the Texas youth depression and suicide research network

There is a tremendous need for brief, valid, and free assessments of anxiety in child mental healthcare. The goal of this study was to determine the psychometric properties of two such measures, the GAD-7 and PROMIS-Anxiety-4a, in 1000 children, adolescents, and young adults (8-20 years-old) with depression and/or suicidality. The GAD-7, the PROMIS-Anxiety-4a, and other validated assessments of anxiety, physical functioning, and psychiatric diagnoses were completed. Confirmatory factor analyses showed an acceptable fit for a single factor in both measures via all indices but the RMSEA. They demonstrated measurement invariance across pre-adolescents (8-12 years-old) and adolescents and emerging adults (13-20 years-old), though scalar invariance was not observed for the GAD-7. Both measures showed strong convergent validity, GAD-7: r = 0.68; PROMIS-Anxiety-4a: r = 0.75, divergent validity with a measure of physical function, GAD-7: r = -0.24; PROMIS-Anxiety-4a: r = -0.28, good internal consistency, ω = 0.89 for both, and high test-retest reliability, GAD-7: r = 0.69; PROMIS-Anxiety-4a: r = 0.71. Both measures also showed acceptable sensitivity and specificity in detecting the presence of any anxiety disorder, GAD-7 cut-off score of 10: AUC = 0.75; PROMIS-Anxiety-4a cutoff score of 12: AUC = 0.79. The GAD-7 correlated similarly with the Screen for Child Anxiety Related Disorders total score and generalized anxiety subscale, and also showed similar diagnostic sensitivity and specificity when used to detect the presence of any anxiety disorder vs. generalized anxiety disorder specifically. Results suggest that both of these brief, publicly available instruments are valid and reliable assessments of anxiety among youth in treatment for depression and/or suicidality.

A Two-Step Real-Time PCR Method To Identify Mycobacterium tuberculosis Infections and Six Dominant Nontuberculous Mycobacterial Infections from Clinical Specimens.

Tuberculosis (TB) is an ongoing threat to public health, and furthermore, the incidence of infections by nontuberculous mycobacteria (NTM), whose symptoms are not distinguishable from TB, is increasing globally, thus indicating a need for accurate diagnostics for patients with suspected mycobacterial infections. Such diagnostic strategies need to include two steps, (i) detecting the mycobacterial infections and, if the case is an NTM infection, (ii) identifying the causative NTM pathogen. To eliminate a false-positive TB diagnosis for a host vaccinated by the bacillus Calmette-Guérin (BCG) strain of Mycobacterium bovis, a new target specific for M. tuberculosis species was selected, together with the species-specific targets for the six dominant NTM species of clinical importance, i.e., M. intracellulare, M. avium, M. kansasii, M. massiliense, M. abscessus, and M. fortuitum. Using sets of primers and probes, a two-step real-time multiplex PCR method was designed. The diagnostic performance was assessed by using a total of 1,772 clinical specimens from patients with suspected TB or NTM infection. A total of 69.4% of M. tuberculosis and 28.8% of NTM infections were positive for the primary step of the real-time PCR corresponding to the culture within 10 weeks, and mycobacterial species of 75.5% of the NTM-positive cases were identified by the secondary step. The two-step method described herein presented promising results and similar diagnostic sensitivity and specificity to commercially available real-time PCR kits for detecting TB and NTM infections. The method also enabled the identification of mycobacterial species in three-quarters of NTM infection cases, thus providing a better treatment strategy. IMPORTANCE Tuberculosis (TB) is an ongoing threat to public health. In addition, infection by nontuberculous mycobacteria (NTM) is a nonnegligible issue for global public health, with increasing incidences. Since the antimicrobial treatment strategy needs to be differed by the causative pathogen, a rapid and accurate diagnostic method is necessary. In this study, we developed a two-step molecular diagnostic method using clinical specimens of TB and NTM infection-suspected patients. The diagnostic power of the new method using the novel target was similar to the widely used TB detection kit, and, among the NTM-positive specimens, three-quarters of the NTM species were able to be identified. This simple and powerful method will be useful as it is, and it could be applied easily to a point-of-care diagnostic apparatus for better application to patients, especially those living in developing countries.

Optimising urinary catecholamine metabolite diagnostics for neuroblastoma.

The analysis of urinary catecholamine metabolites is a cornerstone of neuroblastoma diagnostics. Currently, there is no consensus regarding the sampling method, and variable combinations of catecholamine metabolites are being used. We investigated if spot urine samples can be reliably used for analysis of a panel of catecholamine metabolites for the diagnosis of neuroblastoma. Twenty-four-hour urine or spot urine samples were collected from patients with and without neuroblastoma at diagnosis. Homovanillic acid (HVA), vanillylmandelic acid (VMA), dopamine, 3-methoxytyramine, norepinephrine, normetanephrine, epinephrine and metanephrine were measured by high-performance liquid chromatography coupled with fluorescence detection (HPLC-FD) and/or ultra-performance liquid chromatography coupled with electrospray tandem mass spectrometry (UPLC-MS/MS). Catecholamine metabolite levels were measured in urine samples of 400 neuroblastoma patients (24-hour urine, n = 234; spot urine, n = 166) and 571 controls (all spot urine). Excretion levels of catecholamine metabolites and the diagnostic sensitivity for each metabolite were similar in 24-hour urine and spot urine samples (p > .08 and >.27 for all metabolites). The area under the receiver-operating-characteristic curve (AUC) of the panel containing all eight catecholamine metabolites was significantly higher compared to that of only HVA and VMA (AUC = 0.952 vs. 0.920, p = .02). No differences were observed in metabolite levels between the two analysis methods. Catecholamine metabolites in spot urine and 24-hour urine resulted in similar diagnostic sensitivities. The Catecholamine Working Group recommends the implementation of spot urine as standard of care. The panel of eight catecholamine metabolites has superior diagnostic accuracy over VMA and HVA.

Current Non-Invasive Imaging Techniques Used in the Diagnosis of Adenomyosis

Objective: This review aims to provide insights into the current non-invasive imaging methods used in the diagnosis of adenomyosis, as well as to highlight their diagnostic accuracy, advantages, disadvantages and limitations in the detection of this benign uterine condition. At the same time, this paper emphasizes the importance of using consensus-based terminology in the imaging description of these lesions. Mechanism: A search of PUBMED database was conducted for articles published between January 1998 and August 2022 and studies which compared non-invasive imaging methods with postoperative histology examination of uterine specimens were primarily selected. Transvaginal two-dimensional ultrasound was for a long time the main non-invasive imagistic method used for assessment of adenomyosis lesions. The introduction of Morphological Uterus Sonographic Assessment (MUSA) group criteria yielded a significantly better diagnostic outcome of adenomyosis in case of conventional ultrasonography, but the distinction of concomitant benign uterine conditions still remained challenging. Findings in Brief: The addition of three-dimensional ultrasound or elastosonography to conventional two-dimensional transvaginal ultrasound yielded higher diagnostic sensitivity. Qualitative elastography particularly proved useful in the diagnosis of adenomyosis due to its capacity to achieve differential diagnosis of benign uterine pathologies based on lesion stiffness. Magnetic resonance imaging (MRI) examination presents higher diagnostic specificity and sensitivity, can assess the endometrial and myometrial layers in detail, but its use has been shadowed by costs and significantly longer examination time. Conclusions: The imaging terminology established by consensus by the MUSA group in recent years has facilitated the description of adenomyosis-specific lesions. Two-dimensional transvaginal ultrasound in combination with three-dimensional ultrasound or combined with qualitative elastography offers similar diagnostic sensitivity and specificity to MRI. Despite some limitations, MRI remains a reliable diagnostic method for adenomyosis.

Partial validation of a TaqMan quantitative polymerase chain reaction for the detection of the three genotypes of Infectious spleen and kidney necrosis virus.

Megalocytiviruses (MCVs) are double-stranded DNA viruses known to infect important freshwater and marine fish species in the aquaculture, food, and ornamental fish industries worldwide. Infectious spleen and kidney necrosis virus (ISKNV) is the type species within the genus Megalocytivirus that causes red seabream iridoviral disease (RSIVD) which is a reportable disease to the World Animal Health Organization (WOAH). To better control the transboundary spread of this virus and support WOAH reporting requirements, we developed and partially validated a TaqMan real-time qPCR assay (ISKNV104R) to detect all three genotypes of ISKNV, including the two genotypes that cause RSIVD. Parameters averaged across 48 experiments used a 10-fold dilution series of linearized plasmid DNA (107-101 copies), carrying a fragment of the three-spot gourami iridovirus (TSGIV) hypothetical protein revealed that the assay was linear over 7 orders of magnitude (107-101), a mean efficiency of 99.97 ± 2.92%, a mean correlation coefficient of 1.000 ± 0.001, and a limit of detection (analytical sensitivity) of ≤10 copies of TSGIV DNA. The diagnostic sensitivity and specificity for the ISKNV104R qPCR assay was evaluated and compared to other published assays using a panel of 397 samples from 21 source populations with different prevalence of ISKNV infection (0-100%). The diagnostic sensitivity and specificity for the ISKNV104R qPCR assay was 91.99% (87.28-95.6; 95% CI) and 89.8% (83.53-94.84). The latent class analysis showed that the ISKNV104R qPCR assay had similar diagnostic sensitivities and specificities with overlapping confidence limits compared to a second TaqMan qPCR assay and a SYBR green assay. This newly developed TaqMan assay represents a partially validated qPCR assay for the detection of the three genotypes of the species ISKNV. The ISKNV104R qPCR assay once fully validated, will serve as an improved diagnostic tool that can be used for ISKNV surveillance efforts and diagnosis in subclinical fish to prevent further spread of MCVs throughout the aquaculture and ornamental fish industries.

Artificial Intelligence for Screening of Multiple Retinal and Optic Nerve Diseases

The lack of experienced ophthalmologists limits the early diagnosis of retinal diseases. Artificial intelligence can be an efficient real-time way for screening retinal diseases. To develop and prospectively validate a deep learning (DL) algorithm that, based on ocular fundus images, recognizes numerous retinal diseases simultaneously in clinical practice. This multicenter, diagnostic study at 65 public medical screening centers and hospitals in 19 Chinese provinces included individuals attending annual routine medical examinations and participants of population-based and community-based studies. Based on 120 002 ocular fundus photographs, the Retinal Artificial Intelligence Diagnosis System (RAIDS) was developed to identify 10 retinal diseases. RAIDS was validated in a prospective collected data set, and the performance between RAIDS and ophthalmologists was compared in the data sets of the population-based Beijing Eye Study and the community-based Kailuan Eye Study. The performance of each classifier included sensitivity, specificity, accuracy, F1 score, and Cohen κ score. In the prospective validation data set of 208 758 images collected from 110 784 individuals (median [range] age, 42 [8-87] years; 115 443 [55.3%] female), RAIDS achieved a sensitivity of 89.8% (95% CI, 89.5%-90.1%) to detect any of 10 retinal diseases. RAIDS differentiated 10 retinal diseases with accuracies ranging from 95.3% to 99.9%, without marked differences between medical screening centers and geographical regions in China. Compared with retinal specialists, RAIDS achieved a higher sensitivity for detection of any retinal abnormality (RAIDS, 91.7% [95% CI, 90.6%-92.8%]; certified ophthalmologists, 83.7% [95% CI, 82.1%-85.1%]; junior retinal specialists, 86.4% [95% CI, 84.9%-87.7%]; and senior retinal specialists, 88.5% [95% CI, 87.1%-89.8%]). RAIDS reached a superior or similar diagnostic sensitivity compared with senior retinal specialists in the detection of 7 of 10 retinal diseases (ie, referral diabetic retinopathy, referral possible glaucoma, macular hole, epiretinal macular membrane, hypertensive retinopathy, myelinated fibers, and retinitis pigmentosa). It achieved a performance comparable with the performance by certified ophthalmologists in 2 diseases (ie, age-related macular degeneration and retinal vein occlusion). Compared with ophthalmologists, RAIDS needed 96% to 97% less time for the image assessment. In this diagnostic study, the DL system was associated with accurately distinguishing 10 retinal diseases in real time. This technology may help overcome the lack of experienced ophthalmologists in underdeveloped areas.

Identification of a Novel Antigen for Serological Diagnosis of Scrub Typhus

Scrub typhus is an acute infectious disease caused by the bacterium Orientia tsutsugamushi, which is widely distributed in northern, southern, and eastern Asia. Early diagnosis is essential because the average case fatality rate is usually >10% but can be as high as 45% if antimicrobial treatment is delayed. Although an O. tsutsugamushi 56-kDa type-specific antigen (TSA) is commonly used for serological diagnosis of scrub typhus, the 56-kDa TSA shows variations among O. tsutsugamushi strains, which may lead to poor diagnostic results. Therefore, the discovery of new antigenic proteins may improve diagnostic accuracy. In this study, we identified an O. tsutsugamushi 27 kDa antigen through an immunoinformatic approach and verified its diagnostic potential using patient samples. Compared with the O. tsutsugamushi 56-kDa antigen, the new 27-kDa antigen showed better diagnostic specificity with similar diagnostic sensitivity. Therefore, the O. tsutsugamushi 27-kDa antigen shows potential as a novel serological diagnostic antigen for scrub typhus, providing higher diagnostic accuracy for O. tsutsugamushi than the 56-kDa antigen.

The use of grape juice in the detection of esophageal leaks.

BackgroundEsophagectomies and repair of esophageal perforations are operations used for a variety of clinical indications. Anastomotic leaks are a major post-operative complication after these procedures. At our institution, we routinely use grape juice to detect esophageal leaks in the post-operative setting in addition to other standard imaging modalities. We hypothesize that grape juice can provide similar diagnostic sensitivity and specificity to other modalities for leak detection.MethodsA retrospective review of all patients who underwent an esophagectomy or repair of esophageal perforations from 2013–2019 by the thoracic surgery service at our institution was performed. All patients underwent a barium swallow study, CT imaging or upper endoscopy, as well as ingesting purple grape juice on post-operative day 5 or greater. Purple grape juice observed in the tube thoracostomy drainage system was identified as a positive esophageal leak.ResultsSixty-four patients were included in the study period (25% female, 88% white, median age 62 years old). Sixty-three patients had both a barium swallow study and grape juice test, while one patient underwent CT imaging and grape juice study. Grape juice test sensitivity and specificity were found to be 80% and 98.3%, respectively.ConclusionsThis pilot study demonstrates the effectiveness of using grape juice in detecting esophageal leaks after esophageal operations in patients with tube thoracostomies. Grape juice may be cheaper and potentially less morbid than other studies performed to detect esophageal leaks. Further research is needed to justify the increased use of grape juice in patients who undergo esophageal operations.

Diagnostic sensitivity of vitrectomy and vitreous biopsy for vitritis.

To investigate sensitivity of diagnostic vitrectomy and vitreous biopsy for patients with vitritis of unknown aetiology. Retrospective analysis of all vitrectomies and vitreous biopsies, performed at St Thomas' Hospital, London, UK, for vitritis between February 2001 and February 2019. Patients were identified using the VITREOR database and records were reviewed. Patients were categorised as infectious, non-infectious or masquerade based on final diagnosis. Sensitivity of both diagnostic pars plana vitrectomy (PPV) and vitreous cutter biopsy in each category was investigated. Furthermore, data on gender, age, and method of anaesthesia were also collected. In our cohort, 64 patients underwent PPV with a diagnostic sensitivity of 67% (43/64) overall and 60% (18/30), 56% (9/16) and 89% (16/18) for those with infectious, masquerade and non-infectious aetiologies, respectively. In comparison, 96 patients underwent a vitreous cutter biopsy with diagnostic sensitivity of 74% (71/96) overall and 71% (55/77), 67% (4/6) and 92% (12/13) for those with infectious, masquerade and non-infectious aetiologies, respectively. No statistically significant difference in sensitivity was identified between the vitrectomy and vitreous biopsy groups for either aetiology. Patients undergoing vitrectomy were noted to be older (p = 0.02) and more likely to undergo a general anaesthetic (p < 0.01). Herein we demonstrate similar diagnostic sensitivity of PPV and vitreous cutter biopsy in patients with vitritis of unknown aetiology.

High-sensitivity SARS-CoV-2 group testing by digital PCR among symptomatic patients in hospital settings.

BackgroundWorldwide demand for SARS-CoV-2 RT-PCR testing is still high as testing remains central to follow the disease spread and vaccine efficacy. Group testing has been proposed as a solution to expand testing capabilities but sensitivity concerns may limit its impact on the management of the pandemic. Digital PCR (RT-dPCR) has been shown to be highly sensitive and could help by providing larger testing capabilities without compromising sensitivity.MethodsWe implemented RT-dPCR based COVID-19 group testing on a commercially available system and assay (naica® system from Stilla Technologies) and investigated the sensitivity of the method in real life conditions of a university hospital in Paris, France, in May 2020. We tested the protocol in a direct comparison with reference RT-PCR testing on 448 samples split into groups of 8, 16 and 32 samples for RT-dPCR analysis.ResultsIndividual RT-PCR testing identified 25/448 positive samples. Using 56 groups of 8, RT-dPCR identified 23 groups as positive, corresponding to 26 positive samples by individual PCR (positive percentage agreement 95.2% [95% confidence interval: 76.2–99.9%]) and including 2 samples not detected by individual RT-PCR but confirmed positive by further investigation. 15 of 28 groups of 16 tested positive, corresponding to 25 positive samples by individual PCR (positive percentage agreement 87.5% [95% confidence interval: 61.7–98.4%]). 14 groups of 32 were fully concordant with individual PCR testing but will need to be confirmed on larger datasets.ConclusionsOur proposed approach of group testing by digital PCR has similar diagnostic sensitivity compared to individual RT-PCR testing for group up to 16 samples. This approach reduces the quantity of reagent needed by up to 80% while reducing costs and increasing capabilities of testing up to 10-fold.

Serum-Based Diagnosis of Pediatric Tuberculosis by Assay of Mycobacterium tuberculosis Factors: a Retrospective Cohort Study.

Diagnosis of pediatric tuberculosis (TB) is often complicated by its nonspecific symptoms, paucibacillary nature, and the need for invasive specimen collection techniques. However, a recently reported assay that detects Mycobacterium tuberculosis virulence factors in serum can diagnose various TB manifestations, including paucibacillary TB cases, in adults with good sensitivity and specificity. The current study examined the ability of this M. tuberculosis biomarker assay to diagnose pediatric TB using archived cryopreserved serum samples drawn from children ≤18 years of age who were screened for suspected TB as part of a prospective population-based active surveillance study. In this analysis, any detectable level of either of the M. tuberculosis virulence factors CFP-10 and ESAT-6 was considered direct evidence of TB. Serum samples from 105 children evaluated for TB (55 TB cases and 50 close contacts without TB) were analyzed. The results of this analysis yielded sensitivity of 85.5% (95% confidence interval [CI], 73.3 to 93.5). Similar diagnostic sensitivities were observed for culture-positive (87.5%; 95% CI, 67.6 to 97.3) and culture-negative (83.9%; 95% CI, 66.3 to 94.5) TB cases and for culture negative pulmonary (77.8%; 95% CI, 40.0 to 97.2) and extrapulmonary (86.4%; 95% CI, 65.1 to 97.1) TB cases. These results suggest that serum biomarker analysis holds significant promise for rapid and sensitive diagnosis of pediatric TB cases, including extrapulmonary or paucibacillary TB cases. The ability to use frozen samples for this analysis should also permit assays to be performed at central sites, without a requirement for strict timelines for sample analysis.

Value of enhanced or non-enhanced computed tomography in the detection of rare causes of bowel obstruction

Purpose: This study aims to reveal the uncommon causes of intestinal obstructions and to compare the diagnostic accuracy of enhanced or non-enhanced computed tomography.Materials and Methods: This cohort was a retrospective study of different patients diagnosed with acute mechanical intestinal obstruction in the emergency room or hospital between 15 January 2009 and 15 June 2018. Exclusion criteria were common causes of mechanical bowel obstruction and inclusion criteria were uncommon causes of bowel obstruction. Non-enhanced or enhanced computed tomography were used to diagnose mechanical bowel obstruction.Results: The population included 46 females and 41 males and the age range from 20 to 81. Of the patients with uncommon mechanical obstruction, 58 (66.7 %) were caused by the small intestine, and 29 (33.3%) by the large intestine. When compared to uncommon causes of the small and large bowel with age, body mass index, and use of contrast or not, no significant difference was detected between them. Sensitivity, specificity, positive predictive value, negative predictive value, and diagnostic accuracy of enhanced computed tomography were %93.9, %93.3, %96.9, %87.5, %94 and non-enhanced computed tomography were %96.0, %85.7, %92.3, %92.3, %92.3 respectively.Conclusion: Non-enhanced computed tomography has similar diagnostic accuracy, sensitivity, and specificity compared to enhanced computed tomography for identifying the location, severity, and etiology of bowel obstruction.

Development and validation of nucleic acid tests to diagnose Aleutian mink disease virus

Aleutian disease (AD), caused by Aleutian mink disease virus (AMDV), causes significant welfare problems to mink, and financial losses to the farmers. As there is no vaccine or treatment available, reliable diagnostics is important for disease control. Here, we set up a probe-based real-time PCR (NS1-probe-PCR) to detect all strains of AMDV. PCR was validated and compared to two other real-time PCR methods (pan-AMDV- and pan-AMDO-PCR) currently used for AMDV diagnostics in Finland. The NS1-probe-PCR had a similar detection limit of 20 copies/reaction based on plasmid dilution series, and similar or better diagnostic sensitivity, when evaluated using spleen samples from mink, and stool samples from mink and foxes. None of the three PCR tests cross-reacted with other parvoviruses. The NS1-probe-PCR also showed a significantly higher specificity than the pan-AMDO-PCR with spleen samples and the best specificity with stool samples. Furthermore, it produced the results more rapidly than the other two PCRs making it a promising tool for both diagnostic and research purposes.

Stylet slow-pull vs. standard suction technique for endoscopic ultrasound-guided fine needle biopsy in pancreatic solid lesions using 20 Gauge Procore™ needle: A multicenter randomized trial

BackgroundStandard suction and slow-pull techniques have been utilized during endoscopic ultrasound-guided fine needle aspiration of pancreatic solid lesions, but the correct sampling technique remains unclear. New needles designed to obtain samples suitable for histological evaluation have become available. We performed a study comparing the two sampling methods during endoscopic ultrasound-guided fine needle biopsy (EUS-FNB) in patients with pancreatic solid lesions. MethodsWe performed EUS-FNB with a 20 Gauge FNB needle using slow-pull or standard suction techniques in a prospective, randomized, multicenter study. The primary aim was bloodiness of the collected specimens. Secondary aims were technical success and performance of the two techniques. Results110 patients were included (55 per group). No difference in blood contamination was observed (slow-pull 80% vs. suction 74%, p = 0.917). Technical success was 95% (96% vs. 94%, p = 0315). Sensitivity (96% vs. 93%), specificity (100% vs. 100%), positive likelihood ratio (NA), negative likelihood ratio (0.04 vs. 0.07), diagnostic accuracy (96 vs. 93%) did not differ between the two groups. ConclusionEUS-FNB with slow-pull and standard suction techniques are comparable in terms of blood contamination providing similar high diagnostic sensitivity and accuracy in pancreatic solid lesions. The use of the new generation FNB needle allows to reach such high level of diagnostic adequacy regardless of the technique utilized.

Evaluation of the diagnostic accuracy of smartphone electrocardiogram recorder compared to standard 12 lead electrocardiography in hospital settings

Objectives: To evaluate Smartphone-based Electrocardiogram Recorders (S-ECG-R) diagnostic accuracy compared to standard 12 lead ECG. Methods: A cross-sectional comparative study was conducted in a tertiary cardiac center in Riyadh, Kingdom of Saudi Arabia from December 2017 to February 2018. A total of 403 patients underwent both standard 12 leads ECG and S-ECG-R recordings in the same time. All recordings were checked initially by an electrophysiologist to confirm the accurate diagnosis. Then, the 806 recordings were randomly distributed among 6 certified cardiologists to interpret the rhythms and to evaluate rhythms quality. Results: In this study 211 (52%) males and 192 (48%) females were included, with a mean age of 52±18 years. Of the included rhythms,149 (37%) were abnormal. The majority of which were atrial fibrillation 46 (11%), sinus tachycardia 35 (9%) and premature ventricular contractions 33 (8%). Analysis revealed an overall similar diagnostic sensitivity and specificity of S-ECG-R to the standard 12 lead ECG recording, sensitivity (97.3% versus (vs) 98%) and specificity (99.6% vs. 99.6%). However, cardiologists were more confident during interpreting standard ECG recordings in 91% of the recordings while in 71% of S-ECG-R recordings. Conclusion: The ECG rhythms produced by smartphone accessory have a good diagnostic accuracy in diagnosing arrhythmias. The utility of using S-ECG-R for out-patient is to be determined. Saudi Med J 2019; Vol. 40 (6): 575-581 doi: 10.15537/smj.2019.6.24206 How to cite this article: Towhari J, Masud N, Alanazi H. Evaluation of the diagnostic accuracy of smartphone electrocardiogram recorder compared to standard 12 lead electrocardiography in hospital settings . Saudi Med J 2019; 40 (6): 575-581. doi: 10.15537/smj.2019.6.24206.

Validation of PCR-based protocols for the detection of Echinococcus multilocularis DNA in the final host using the Intestinal Scraping Technique as a reference

Oral uptake of infectious Echinococcus multilocularis eggs shed by canids with their faeces may lead to development of alveolar echinococcosis in humans, which is clinically similar to a malignant infiltrative tumor and may be fatal if left untreated. E. multilocularis is therefore regarded as one of the most important and neglected metazoan parasites in the Northern hemisphere. The diagnosis of this tapeworm in the final host plays a key role in the epidemiology of E. multilocularis.The diagnostic performance of a magnetic-capture (MC) DNA extraction protocol in combination with a minor groove-binder real time PCR (MC-MGBqPCR) for the detection of E. multilocularis eggs was determined relative to a highly sensitive variant of the Intestinal Scraping Technique (IST) using faecal samples of foxes. In addition, we compared results obtained by MC-MGBqPCR with those of a previously validated protocol (QIAamp Fast DNA Stool Mini Kit (QT) combined with a TaqMan qPCR). Furthermore, a workflow using the NucleoMagVet DNA extraction kit (NM) in combination with MGBqPCR and TaqMan-qPCR was also included in the comparisons.To estimate the analytical sensitivity, phosphate-buffered saline and fox faecal samples were spiked with different numbers of eggs and tested in defined combinations of DNA extraction and PCR protocols. To assess the diagnostic sensitivity of the different workflows, samples were used that had been collected from the ampulla recti or the rectum of 120 foxes hunted in Brandenburg, Germany. The samples represented five IST categories formed according to the E. multilocularis worm burden of the foxes. For DNA extraction by MC or using two other commercial extraction kits, the supernatants obtained from 3 g of bead-beaten faecal samples were used. The extracted DNAs were then processed in the respective PCR protocols.The MC-MGBqPCR showed the highest diagnostic sensitivity (93%; 95% Confidence Interval (CI): 86–97%) relative to IST. The QT extraction protocol in combination with TaqMan-qPCR had the second highest sensitivity (89%; 95% CI: 80–94%), followed by NM with MGBqPCR (86%; 95% CI: 77–93%) in comparison to IST. The lowest diagnostic sensitivity was found for the NM combined with the TaqMan-qPCR protocol (72%; 95% CI: 62–82%).In conclusion, the MC-MGBqPCR seems to represent a suitable alternative to IST. However, applied to 3 g faecal samples, the less costly QT-TaqMan-qPCR workflow yielded a similar diagnostic sensitivity relative to IST. However, differences between these two workflows were not statistically significant.

Diagnostic performance of multiplex PCR on pulmonary samples versus nasopharyngeal aspirates in community-acquired severe lower respiratory tract infections

BackgroundPCR-based techniques for the diagnosis of community- acquired severe lower respiratory tract infections are becoming the standard of care. However, their relative ability to identify either atypical bacteria or viruses that cause LRTI from clinical samples from various sources is yet to be determined. Objectives and study designThe aim of our study was to compare the diagnostic yield of nasopharyngeal aspirates with that of pulmonary samples for the etiological diagnosis of severe acute lower respiratory tract infections by multiplex PCR. Patients were adults with community-acquired pneumonia or acute exacerbation of chronic obstructive pulmonary disease. ResultsWe obtained concordant results for 81 (79%) of the 103 pairs of samples. In 14 of the 22 discordant results, more pathogens were evidenced in the lower respiratory tract samples. ConclusionsPulmonary samples had a similar diagnostic sensitivity for virus detection by multiplex PCR as nasopharyngeal aspirates. In contrast, in our study, the diagnostic efficacy of pulmonary samples for Legionella pneumophila over simple aspirates was clearly superior.

Noninvasive EGFR testing in plasma circulating free DNA (cfDNA) by a new diagnostic method to detect point mutations, deletions and insertions associated to non small cell lung cancer: CLART CMA EGFR LB.

e20008 Background: Epidermal growth factor receptor tyrosine kinase inhibitors (EGFR-TKIs) are current treatments for advanced non-small cell lung cancer (NSCLC) with activating EGFR gene mutations. Histological samples are the standard tumor materials for EGFR mutation analysis. However, the accessibility of tumor samples is not always possible in advanced NSCLC patients. Moreover, a high percentage of EGFR mutated NSCLC patients will develop resistance to EGFR-TKIs such as T790M mutation. CLART CMA EGFR LB is a novel diagnostic assay able to detect 39 high-prevalence mutations associated with sensitivity or resistance to tyrosine kinase inhibitor treatment. Methods: A highly sensitive and specific method was developed for detection of EGFR mutations (G719X, T790M, L858R, L861Q, insertions in exon 20, and deletions in exon 19) in plasma samples (cfDNA). CLART CMA EGFR LB is based on a preamplification step with a multiplex ARMS-PCR and microarray detection system. Clinical testing was performed using 51 clinical plasma samples: 27 contained L858R, T790M, and deletions in exon 19; 24 contained wild type alleles. 20 samples were cross checked by next generation sequencing performed on the PGM platform (Ion Ampliseq™ Custom, deep-coverage 15000x). Results: Analytical sensitivity was assessed using recombinant plasmids, results ranged between 10-1000 copies/5µl for all mutations. cfDNA from cell lines with the mutations L858R, T790M and deletions in exon 19 at different frequencies (cfDNA Reference Standard, Horizon) were assessed. The system was able to detect the mutations present in a frequency of 2%. The analysis of 51 samples allowed establishing the diagnostic sensitivity and specificity in 93.33% and 100% respectively. CLART CMA EGFR LB showed similar analytical and diagnostic sensitivity than NGS for detecting L858R, T790M and deletions in exon 19. Conclusions: Our data support the use of CLART CMA EGFR LB for clinical testing prior to the selection of the appropriate treatment in NSCLC, monitoring the patient evolution and the emergence of resistance mutations such as T790M in plasma samples.

Well-differentiated bronchial neuroendocrine tumors: Clinical management and outcomes in 105 patients.

Bronchial neuroendocrine tumors (NETs) are rare tumors representing approximately 20%-30% of all neuroendocrine tumors and 2%-3% of all adult lung cancers. Here, they present a large case series of well-differentiated bronchial NETs with the aim of investigating the behavior of these tumors and long-term outcomes. A retrospective review was performed of 105 patients with bronchial NETs managed in a tertiary referral center in the period between January 1998 and January 2012. Bronchial NETs are commoner in females and the commonest presenting symptoms were cough (13.9%) and dyspnoea (11.6%). OctreoscanTM and Gallium-68 DOTATATE PET were found to have similar diagnostic sensitivity and FDG PET was more sensitive for higher-grade tumors. Over a median follow-up period of 35.5 months mortality rate was 5.7%. The 5-year survival was 76% and the 10-year survival was 62%. Female patients survived longer but this difference was not statistically significant (P = .59). Older age greater than 50 years (P = .027), higher levels of Chromogranin A (CgA) (P = .034), first-line treatment with surgery (P = .005), ki67 over 10% (P = .037), and tumor stage (P = .036) but not tumor grade (P = .22), were significantly associated with survival. Several factors have been identified which are independently associated with survival including CgA levels greater than 100 pmol/L, tumor stage, age greater than 50, ki67 over 10% and having surgery as first-line treatment. There was no difference in survival between typical and atypical carcinoids.