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The American Journal of Tropical... Apr 2021Cholera is a severe acute, highly transmissible diarrheal disease which affects many low- and middle-income countries. Outbreaks of cholera are confirmed using...
Cholera is a severe acute, highly transmissible diarrheal disease which affects many low- and middle-income countries. Outbreaks of cholera are confirmed using microbiological culture, and additional cases during the outbreak are generally identified based on clinical case definitions, rather than laboratory confirmation. Many low-resource areas where cholera occurs lack the capacity to perform culture in an expeditious manner. A simple, reliable, and low-cost rapid diagnostic test (RDT) would improve identification of cases allowing rapid response to outbreaks. Several commercial RDTs are available for cholera testing with two lines to detect either serotypes O1 and O139; however, issues with sensitivity and specificity have not been optimal with these bivalent tests. Here, we report an evaluation of a new commercially available cholera dipstick test which detects only serotype O1. In both laboratory and field studies in Kenya, we demonstrate high sensitivity (97.5%), specificity (100%), and positive predictive value (100%) of this new RDT targeting only serogroup O1. This is the first field evaluation for the new Crystal VC-O1 RDT; however, with these high-performance metrics, this RDT could significantly improve cholera outbreak detection and improve surveillance for better understanding of cholera disease burden.
Topics: Adolescent; Adult; Child; Child, Preschool; Cholera; Clinical Laboratory Techniques; Diarrhea; Disease Outbreaks; Feces; Humans; Infant; Infant, Newborn; Kenya; Predictive Value of Tests; Reagent Kits, Diagnostic; Sensitivity and Specificity; Serogroup; Vibrio cholerae O1; Young Adult
PubMed: 33819171
DOI: 10.4269/ajtmh.20-1280 -
Frontiers in Cellular and Infection... 2021The emerging Coronavirus Disease-2019 (COVID-19) has challenged the public health globally. With the increasing requirement of detection for SARS-CoV-2 outside of the...
BACKGROUND
The emerging Coronavirus Disease-2019 (COVID-19) has challenged the public health globally. With the increasing requirement of detection for SARS-CoV-2 outside of the laboratory setting, a rapid and precise Point of Care Test (POCT) is urgently needed.
METHODS
Targeting the nucleocapsid (N) gene of SARS-CoV-2, specific primers, and probes for reverse transcription recombinase-aided amplification coupled with lateral flow dipstick (RT-RAA/LFD) platform were designed. For specificity evaluation, it was tested with human coronaviruses, human influenza A virus, influenza B viruses, respiratory syncytial virus, and hepatitis B virus, respectively. For sensitivity assay, it was estimated by templates of recombinant plasmid and pseudovirus of SARS-CoV-2 RNA. For clinical assessment, 100 clinical samples (13 positive and 87 negatives for SARS-CoV-2) were tested quantitative reverse transcription PCR (RT-qPCR) and RT-RAA/LFD, respectively.
RESULTS
The limit of detection was 1 copies/μl in RT-RAA/LFD assay, which could be conducted within 30 min at 39°C, without any cross-reaction with other human coronaviruses and clinical respiratory pathogens. Compared with RT-qPCR, the established POCT assay offered 100% specificity and 100% sensitivity in the detection of clinical samples.
CONCLUSION
This work provides a convenient POCT tool for rapid screening, diagnosis, and monitoring of suspected patients in SARS-CoV-2 endemic areas.
Topics: COVID-19; COVID-19 Nucleic Acid Testing; Coronavirus Nucleocapsid Proteins; DNA Primers; Humans; Phosphoproteins; Point-of-Care Testing; RNA, Viral; Real-Time Polymerase Chain Reaction; Recombinases; Reverse Transcription; SARS-CoV-2; Sensitivity and Specificity
PubMed: 33598439
DOI: 10.3389/fcimb.2021.613304 -
Journal of Veterinary Science Jan 2021Quantitation of urine protein is important in dogs with chronic kidney disease. Various analyzers are used to measure urine protein-to-creatinine ratios (UPCR). (Comparative Study)
Comparative Study
BACKGROUND
Quantitation of urine protein is important in dogs with chronic kidney disease. Various analyzers are used to measure urine protein-to-creatinine ratios (UPCR).
OBJECTIVES
This study aimed to compare the UPCR obtained by three types of analyzers (automated wet chemistry analyzer, in-house dry chemistry analyzer, and dipstick reading device) and investigate whether the differences could affect clinical decision process.
METHODS
Urine samples were collected from 115 dogs. UPCR values were obtained using three analyzers. Bland-Altman and Passing Bablok tests were used to analyze agreement between the UPCR values. Urine samples were classified as normal or proteinuria based on the UPCR values obtained by each analyzer and concordance in the classification evaluated with Cohen's kappa coefficient.
RESULTS
Passing and Bablok regression showed that there were proportional as well as constant difference between UPCR values obtained by a dipstick reading device and those obtained by the other analyzers. The concordance in the classification of proteinuria was very high (κ = 0.82) between the automated wet chemistry analyzer and in-house dry chemistry analyzer, while the dipstick reading device showed moderate concordance with the automated wet chemistry analyzer (κ = 0.52) and in-house dry chemistry analyzer (κ = 0.53).
CONCLUSIONS
Although the urine dipstick test is simple and a widely used point-of-care test, our results indicate that UPCR values obtained by the dipstick test are not appropriate for clinical use. Inter-instrumental variability may affect clinical decision process based on UPCR values and should be emphasized in veterinary practice.
Topics: Animals; Creatinine; Diagnostic Tests, Routine; Dog Diseases; Dogs; Female; Male; Proteinuria; Urinalysis
PubMed: 33522166
DOI: 10.4142/jvs.2021.22.e14 -
Basic & Clinical Pharmacology &... May 2021The metabolite of ethanol, ethyl glucuronide (EtG), reflects alcohol intake longer than ethanol and is used as a biomarker in clinical settings to detect alcohol use. We... (Observational Study)
Observational Study
The metabolite of ethanol, ethyl glucuronide (EtG), reflects alcohol intake longer than ethanol and is used as a biomarker in clinical settings to detect alcohol use. We aimed to assess the clinical usefulness in a low-to-moderate alcohol intake setting and validate a new urine EtG dipstick. A three-way, open, cross-over trial was conducted. Data were collected from January to June 2019. Among 12 healthy female volunteers, we quantified urine EtG and used a dipstick following intake of either one, two or four units of alcohol. Main outcomes were concentrations of EtG in urine and serum, and creatinine and ethanol in serum. EtG in urine was determined dichotomously by dipsticks at two different thresholds and by mass spectrometry used as gold standard. EtG in urine was quantifiable up to 24 hours after alcohol intake. In some individual cases, EtG was quantifiable up to 72 hours at low concentrations. The dipstick detected EtG in urine up to 24 hours. At thresholds of 1000 and 1500 ng/mL, the dipsticks had a specificity of 100% (both), while sensitivity was 84% and 69%, respectively. The sensitivity of the dipsticks was insufficient to support a screening purpose in this setting of low-to-moderate alcohol intake.
Topics: Adult; Alcohol Drinking; Ethanol; Feasibility Studies; Female; Glucuronates; Healthy Volunteers; Humans; Mass Screening; Mass Spectrometry; Maternal-Fetal Exchange; Pregnancy; Sensitivity and Specificity; Urinalysis; Young Adult
PubMed: 33438372
DOI: 10.1111/bcpt.13558 -
Frontiers in Bioengineering and... 2020Early diagnostics and point-of-care (POC) devices can save people's lives or drastically improve their quality. In particular, millions of diabetic patients worldwide...
Early diagnostics and point-of-care (POC) devices can save people's lives or drastically improve their quality. In particular, millions of diabetic patients worldwide benefit from POC devices for frequent self-monitoring of blood glucose. Yet, this still involves invasive sampling processes, which are quite discomforting for frequent measurements, or implantable devices dedicated to selected chronic patients, thus precluding large-scale monitoring of the globally increasing diabetic disorders. Here, we report a non-invasive colorimetric sensing platform to identify hyperglycemia from saliva. We designed plasmonic multibranched gold nanostructures, able to rapidly change their shape and color (naked-eye detection) in the presence of hyperglycemic conditions. This "reshaping approach" provides a fast visual response and high sensitivity, overcoming common detection issues related to signal (color intensity) losses and bio-matrix interferences. Notably, optimal performances of the assay were achieved in real biological samples, where the biomolecular environment was found to play a key role. Finally, we developed a dipstick prototype as a rapid home-testing kit.
PubMed: 33425867
DOI: 10.3389/fbioe.2020.601216 -
PloS One 2020Previous studies on diagnostic accuracy of dipstick testing for leukocyte esterase (LE) and nitrite to diagnose urinary tract infection (UTI) had used urine culture,...
OBJECTIVE
Previous studies on diagnostic accuracy of dipstick testing for leukocyte esterase (LE) and nitrite to diagnose urinary tract infection (UTI) had used urine culture, which is an imperfect gold standard. Estimates of diagnostic accuracy obtained using the classical gold standard framework might not reflect the true diagnostic accuracy of dipstick tests.
METHODS
We used the dataset from a prospective, observational study conducted in the emergency department of a teaching hospital in southern India. Patients with a clinical suspicion of UTI underwent dipstick testing for LE and nitrite, urine microscopy, and urine culture. Based on the results of urine microscopy and culture, UTI was classified into definite, probable, and possible. Patients with microscopic pyuria and a positive urine culture were adjudicated as definite UTI. Unequivocal imaging evidence of emphysematous pyelonephritis or perinephric collections was also considered definite UTI. We estimated the diagnostic accuracy of LE and nitrite tests using the classical analysis (assuming definite UTI as gold standard) and two different Bayesian latent class models (LCMs; 3-tests in 1-population and 2-tests in 2-populations models).
RESULTS
We studied 149 patients. Overall, 64 (43%) patients had definite, 76 (51%) had probable, and 2 (1.3%) had possible UTI; 7 (4.6%) had alternate diagnoses. In classical analysis, LE was more sensitive than nitrite (87.5% versus 70.5%), while nitrite was more specific (24% versus 58%). The 3-tests in 1-population Bayesian LCM indicated a substantially better sensitivity and specificity for LE (98.1% and 47.6%) and nitrite (88.2% and 97.7%). True sensitivity and specificity of urine culture as estimated by the model was 48.7% and 73.0%. Estimates of the 2-tests in 2-populations model were in agreement with the 3-tests in 1-population model.
CONCLUSIONS
Bayesian LCMs indicate a clinically important improvement in the true diagnostic accuracy of urine dipstick testing for LE and nitrite. Given this, a negative dipstick LE would rule-out UTI, while a positive dipstick nitrite would rule-in UTI in our study setting. True diagnostic accuracy of urine dipstick testing for UTI in various practice settings needs reevaluation using Bayesian LCMs.
Topics: Adult; Aged; Bacteriuria; Bayes Theorem; Escherichia coli Infections; Female; Humans; Latent Class Analysis; Male; Middle Aged; Prospective Studies; Pyuria; Reagent Strips; Sensitivity and Specificity; Urinalysis
PubMed: 33382863
DOI: 10.1371/journal.pone.0244870 -
Journal of the American Medical... Jun 2021There is unmet need for an easy, noninvasive urine collection method to diagnose urinary tract infections (UTIs) in nursing home residents suffering from urinary...
OBJECTIVE
There is unmet need for an easy, noninvasive urine collection method to diagnose urinary tract infections (UTIs) in nursing home residents suffering from urinary incontinence or cognitive impairments. UTIs are highly prevalent in nursing home residents, and urine specimen collection can be difficult. The objective of this study was to assess if urine specimens collected from super-absorbing incontinence pads (adult diapers) are a reliable collection method for UTI diagnosis.
DESIGN
This was a paired noninferiority laboratory study, in which pairing refers to UTI diagnostics performed directly using clinical urine specimens (reference specimen) and indirectly using urine extracted from diapers (diaper specimen).
SETTING AND PARTICIPANTS
In this study, remnants of 250 clinical urine specimens were used to assess noninferiority in diagnosing UTIs, based on a 1-sided type I error of 2.5%, a power of 90%, and a noninferiority margin of 15%.
METHODS
Urine specimens were poured on super-absorbing disposable adult diapers and extracted after 3 hours, to use for dipstick urinalysis and bacterial culture. UTIs were defined as presence of leukocytes and a positive bacterial culture. Noninferiority was assessed by calculating a Wald-type test statistic.
RESULTS
Noninferiority was established for diagnosing UTIs in diaper specimens, and for each of its components (dipstick leukocyte detection and bacterial culture positivity). Positive bacterial cultures were found in 72 (29.0%) diaper specimens compared with 65 (26.2%) reference specimens (difference -2.8%, 97.5% CI -7.1% to 1.5%). Leukocytes were present in 162 (64.8%) diaper specimens, compared with 175 (70.0%) reference specimens (difference -5.7%, 97.5% CI: -10.6% to -0.7%).
CONCLUSION AND IMPLICATIONS
Our results on diagnosing UTIs, by dipstick analysis and bacterial cultures, using super-absorbing adult diapers are promising. Before translation into clinical practice, further studies are needed to evaluate the risk of bacterial contamination by wearing adult diapers, possibly resulting in overdiagnosis of UTI.
Topics: Adult; Humans; Incontinence Pads; Nursing Homes; Urinalysis; Urinary Incontinence; Urinary Tract Infections
PubMed: 33303395
DOI: 10.1016/j.jamda.2020.10.003 -
Foods (Basel, Switzerland) Nov 2020Soybean () allergy can be life threatening. A lack of causative immunotherapy of soybean allergy makes soybean avoidance indispensable. Detection methods are essential...
Soybean () allergy can be life threatening. A lack of causative immunotherapy of soybean allergy makes soybean avoidance indispensable. Detection methods are essential to verify allergen labeling and unintentional allergen cross contact during food manufacture. Here, we aimed at evaluating our previously described primers for loop-mediated isothermal amplification (LAMP) of multicopy gene , combined with a lateral flow dipstick (LFD)-like detection, for their performance of soybean detection in complex food matrices. The results were compared with those obtained using quantitative real-time Polymerase Chain Reaction (qPCR) as the current standard of DNA-based allergen detection, and antibody-based commercial lateral flow device (LFD) as the current reference of protein-based rapid allergen detection. LAMP-LFD allowed unequivocal and reproducible detection of 10 mg/kg soybean incurred in three representative matrices (boiled sausage, chocolate, instant tomato soup), while clear visibility of positive test lines of two commercial LFD tests was between 10 and 10 mg/kg and depending on the matrix. Sensitivity of soybean detection in incurred food matrices, commercial retail samples, as well as various processed soybean products was comparable between LAMP-LFD and qPCR. The DNA-based LAMP-LFD proved to be a simple and low-technology soybean detection tool, showing sensitivity and specificity that is comparable or superior to the investigated commercial protein-based LFD.
PubMed: 33255927
DOI: 10.3390/foods9121741 -
BMC Pregnancy and Childbirth Nov 2020Hypertensive disorders of pregnancy (HDP) are associated with high maternal mortality in Ghana and globally. Evidence shows that there is poor availability of...
BACKGROUND
Hypertensive disorders of pregnancy (HDP) are associated with high maternal mortality in Ghana and globally. Evidence shows that there is poor availability of pregnancy-related point-of-care (POC) tests in Ghana's primary healthcare (PHC) clinics (health centre or community-based health planning services facilities). Therefore, we employed geographic information systems to estimate the geographical distribution of and physical accessibility to HDP POC testing services in the Upper East Region (UER), Ghana.
METHODS
We collected data on 100 out of 365 PHC clinics, public hospitals providing HDP testing, PHC clinic type, ownership, and availability of urine dipsticks and blood pressure (BP) devices. We also obtained the geo-located data of the PHC clinics and hospitals using the global positioning system. We employed ArcGIS 10.4 to measure the distance and travel time from the location of each PHC clinic without HDP POC testing services as well as from all locations of each district to the nearest hospital/clinic where the service is available. The travel time was estimated using an assumed motorised tricycle speed of 20 km/hour. We further calculated the spatial distribution of the hospitals/clinics providing HDP POC testing services using the spatial autocorrelation tool in ArcMap, and Stata version 14 for descriptive statistical analysis.
RESULTS
Of the 100 participating PHC clinics, POC testing for HDP was available in 19% (14% health centres and 5% community-based health planning services compounds) in addition to the 10 hospitals use as referral points for the service. The findings indicated that the spatial pattern of the distribution of the health facilities providing HDP POC testing was random (z-score = -0.61; p = 0.54). About 17% of the PHC clinics without HDP POC testing service were located > 10 km to the nearest facility offering the service. The mean distance and travel time from PHC clinics without HDP POC testing to a health facility providing the service were 11.4 ± 9.9 km and 31.1 ± 29.2 min respectively. The results suggest that if every 19% of the 365 PHC clinics are offering HDP POC testing in addition to these 10 hospitals identified, then the estimated coverage (health facility-to-women in fertility age ratio) in the UER is 1: 3,869.
CONCLUSIONS
There is poor physical accessibility to HDP POC testing services from PHC clinics without HDP POC testing in the UER. Mothers who obtain maternal healthcare in about 17% of the PHC clinics travel long distances (> 10 km) to access the service when needed. Hence, there is a need to improve the availability of HDP POC diagnostic tests in Ghana's rural clinics.
Topics: Female; Geographic Information Systems; Geography; Ghana; Health Services Accessibility; Humans; Hypertension, Pregnancy-Induced; Maternal Health Services; Point-of-Care Testing; Pregnancy; Primary Health Care; Rural Population; Spatial Analysis; Travel
PubMed: 33238918
DOI: 10.1186/s12884-020-03441-6 -
International Journal of Molecular... Nov 2020Potato is an important staple food crop in both developed and developing countries. However, potato plants are susceptible to several economically important viruses that...
Potato is an important staple food crop in both developed and developing countries. However, potato plants are susceptible to several economically important viruses that reduce yields by up to 50% and affect tuber quality. One of the major threats is corky ringspot, which is a tuber necrosis caused by tobacco rattle virus (TRV). The appearance of corky ringspot symptoms on tubers prior to commercialization results in ≈ 45% of the tubers being downgraded in quality and value, while ≈ 55% are declared unsaleable. To improve current disease management practices, we have developed simple diagnostic methods for the reliable detection of TRV without RNA purification, involving minimalized sample handling (mini), subsequent improved colorimetric loop-mediated isothermal amplification (LAMP), and final verification by lateral-flow dipstick (LFD) analysis. Having optimized the mini-LAMP-LFD approach for the sensitive and specific detection of TRV, we confirmed the reliability and robustness of this approach by the simultaneous detection of TRV and other harmful viruses in duplex LAMP reactions. Therefore, our new approach offers breeders, producers, and farmers an inexpensive and efficient new platform for disease management in potato breeding and cultivation.
Topics: Colorimetry; Humans; Molecular Diagnostic Techniques; Molecular Typing; Nucleic Acid Amplification Techniques; Plant Diseases; Plant Tubers; Plant Viruses; RNA, Viral; Reproducibility of Results; Sensitivity and Specificity; Solanum tuberosum
PubMed: 33228234
DOI: 10.3390/ijms21228741