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Malaria Journal Nov 2015Isothermal amplification techniques are emerging as a promising method for malaria diagnosis since they are capable of detecting extremely low concentrations of parasite...
BACKGROUND
Isothermal amplification techniques are emerging as a promising method for malaria diagnosis since they are capable of detecting extremely low concentrations of parasite target while mitigating the need for infrastructure and training required by other nucleic acid based tests. Recombinase polymerase amplification (RPA) is promising for further development since it operates in a short time frame (<30 min) and produces a product that can be visually detected on a lateral flow dipstick. A self-sealing paper and plastic system that performs both the amplification and detection of a malaria DNA sequence is presented.
METHODS
Primers were designed using the NCBI nBLAST tools and screened using gel electrophoresis. Paper and plastic devices were prototyped using commercial design software and parts were cut using a laser cutter and assembled by hand. Synthetic copies of the Plasmodium 18S gene were spiked into solution and used as targets for the RPA reaction. To test the performance of the device the same samples spiked with synthetic target were run in parallel both in the paper and plastic devices and using conventional bench top methods.
RESULTS
Novel RPA primers were developed that bind to sequences present in the four species of Plasmodium which infect humans. The paper and plastic devices were found to be capable of detecting as few as 5 copies/µL of synthetic Plasmodium DNA (50 copies total), comparable to the same reaction run on the bench top. The devices produce visual results in an hour, cost approximately $1, and are self-contained once the device is sealed.
CONCLUSIONS
The device was capable of carrying out the RPA reaction and detecting meaningful amounts of synthetic Plasmodium DNA in a self-sealing and self-contained device. This device may be a step towards making nucleic acid tests more accessible for malaria detection.
Topics: Costs and Cost Analysis; DNA, Protozoan; DNA, Ribosomal; Equipment and Supplies; Humans; Malaria; Molecular Diagnostic Techniques; Nucleic Acid Amplification Techniques; Paper; Plasmodium; Plastics; RNA, Ribosomal, 18S; Time Factors
PubMed: 26611141
DOI: 10.1186/s12936-015-0995-6 -
BMC Cardiovascular Disorders Nov 2021Atherosclerosis is a vital cause of cardiovascular diseases. The correlation between proteinuria and atherosclerosis, however, has not been confirmed. This study aimed... (Observational Study)
Observational Study
BACKGROUND AND AIMS
Atherosclerosis is a vital cause of cardiovascular diseases. The correlation between proteinuria and atherosclerosis, however, has not been confirmed. This study aimed to assess whether there is a relationship between proteinuria and atherosclerosis.
METHODS
From January 2016 to September 2020, 13,545 asymptomatic subjects from four centres in southern China underwent dipstick proteinuria testing and carotid atherosclerosis examination. Data on demography and past medical history were collected, and laboratory examinations were performed. The samples consisted of 7405 subjects (4875 males and 2530 females), excluding subjects failing to reach predefined standards and containing enough information. A multivariate logistic regression model was used to adjust the influence of traditional risk factors for atherosclerosis on the results.
RESULTS
Compared with proteinuria-negative subjects, proteinuria-positive subjects had a higher prevalence rate of carotid atherosclerosis. The differences were statistically significant (22.6% vs. 26.7%, χ = 10.03, p = 0.002). After adjusting for common risk factors for atherosclerosis, age, sex, BMI, blood lipids, blood pressure, renal function, hypertensive disease, diabetes mellitus and hyperlipidaemia, proteinuria was an independent risk factor for atherosclerosis (OR = 1.191, 95% CI 1.015-1.398, p = 0.033). The Hosmer-Lemeshow test was used to test the risk prediction model of atherosclerosis, and the results showed that the model has high goodness of fit and strong independent variable prediction ability.
CONCLUSIONS
Proteinuria is independently related to carotid atherosclerosis. With the increase in proteinuria level, the risk of carotid atherosclerotic plaque increases. For patients with positive proteinuria, further examination of atherosclerosis should not be ignored.
Topics: Adolescent; Adult; Aged; Aged, 80 and over; Carotid Artery Diseases; China; Cross-Sectional Studies; Female; Humans; Male; Middle Aged; Predictive Value of Tests; Prognosis; Proteinuria; Reagent Strips; Risk Assessment; Risk Factors; Ultrasonography, Doppler, Color; Urinalysis; Young Adult
PubMed: 34798829
DOI: 10.1186/s12872-021-02367-x -
Journal of Epidemiology Jan 2021Previous studies have suggested the potential association between renal diseases and gallstone. The extent of proteinuria is recognized as a marker for the severity of...
BACKGROUND
Previous studies have suggested the potential association between renal diseases and gallstone. The extent of proteinuria is recognized as a marker for the severity of chronic kidney disease. However, little data is available to identify the risk of incident gallstone according to the level of proteinuria.
METHODS
Using a data of 207,356 Koreans registered in National Health Insurance Database, we evaluated the risk of gallstone according to the levels of urine dipstick proteinuria through an average follow-up of 4.36 years. Study subjects were divided into 3 groups by urine dipstick proteinuria (negative: 0, mild: 1+ and heavy: 2+ or greater). Multivariate Cox-proportional hazard model was used to assess the adjusted hazard ratios (HRs) and 95% confidence intervals (CIs) for incident cholelithiasis according to urine dipstick proteinuria.
RESULTS
The group with higher urine dipstick proteinuria had worse metabolic, renal, and hepatic profiles than those without proteinuria, which were similarly observed in the group with incident cholelithiasis. The heavy proteinuria group had the greatest incidence of cholelithiasis (2.39%), followed by mild (1.54%) and negative proteinuria groups (1.39%). Analysis for multivariate Cox-proportional hazard model indicated that the heavy proteinuria group had higher risk of cholelithiasis than other groups (negative: reference, mild proteinuria: HR 0.97 [95% CI, 0.74-1.26], and heavy proteinuria: HR 1.46 [95% CI, 1.09-1.96]).
CONCLUSION
Urine dipstick proteinuria of 2+ or greater was significantly associated with increased risk for incident gallstone.
Topics: Adult; Biomarkers; Cholelithiasis; Databases, Factual; Female; Gallstones; Glomerular Filtration Rate; Humans; Incidence; Male; Middle Aged; Predictive Value of Tests; Proteinuria; Republic of Korea; Risk Factors; Urinalysis
PubMed: 31956168
DOI: 10.2188/jea.JE20190223 -
Biosensors Apr 2020Point-of-care (POC) diagnostics enables the diagnosis and monitoring of patients from the clinic or their home. Ideally, POC devices should be compact, portable and...
Point-of-care (POC) diagnostics enables the diagnosis and monitoring of patients from the clinic or their home. Ideally, POC devices should be compact, portable and operatable without the requirement of expertise or complex fluid mechanical controls. This paper showcases a chip-and-dip device, which works on the principle of capillary-driven flow microfluidics and allows analytes' detection by multiple microchannels in a single microchip via smartphone imaging. The chip-and-dip device, fabricated with inexpensive materials, works by simply dipping the reagents-coated microchip consisting of microchannels into a fluidic sample. The sample is loaded into the microchannels via capillary action and reacts with the reagents to produce a colourimetric signal. Unlike dipstick tests, this device allows the loading of bacterial/pathogenic samples for antimicrobial testing. A single device can be coated with multiple reagents, and more analytes can be detected in one sample. This platform could be used for a wide variety of assays. Here, we show the design, fabrication and working principle of the chip-and-dip flow device along with a specific application consisting in the determination of β-lactamase activity and cortisol. The simplicity, robustness and multiplexing capability of the chip-and-dip device will allow it to be used for POC diagnostics.
Topics: Colorimetry; Equipment Design; Humans; Lab-On-A-Chip Devices; Microfluidics; Point-of-Care Testing; Smartphone
PubMed: 32326641
DOI: 10.3390/bios10040039 -
Cleveland Clinic Journal of Medicine Mar 2008Although major health organizations do not support screening for hematuria by dipstick testing, millions of patients without symptoms are tested yearly. Since urinary... (Review)
Review
Although major health organizations do not support screening for hematuria by dipstick testing, millions of patients without symptoms are tested yearly. Since urinary dipstick tests for hematuria have a high false-positive rate, patients with positive dipstick results require microscopic urinalysis before the diagnosis of hematuria can be made. Primary care physicians can help protect patients from the anxiety, costs, and risks of an unnecessary urologic workup by adhering to the principles of early hematuria management.
Topics: Decision Trees; Hematuria; Humans; Magnetic Resonance Imaging; Reagent Strips; Referral and Consultation; Risk Factors; Severity of Illness Index; Tomography, X-Ray Computed; Urinalysis; Urography; Urologic Diseases
PubMed: 18383931
DOI: 10.3949/ccjm.75.3.227 -
Archivos Espanoles de Urologia Jul 2020Urinary pH is a decisive factor in several pathologies, there by an informative marker employed in treatment decisions. Although extensively used, the urinary pH...
OBJECTIVES
Urinary pH is a decisive factor in several pathologies, there by an informative marker employed in treatment decisions. Although extensively used, the urinary pH dipstick test may not be sufficiently accurate or precise for clinical decisions and more robust methodologies need to be considered. In this study, we compare pH measurements when using aportable medical device and different dipstick tests.
MATERIALS AND METHODS
Four pH dipstick brands and a Lit-Control® pH Meter were tested using commercial buffer solutions with seven distinct pH values representing the physiological range in urine (4.66; 5.0;5.5; 6.0; 7.0; 7.5; 8.0). A statistical analysis was performed to assess the correlation of measured versus real values, together with validity measures as resolution,precision and accuracy.
RESULTS
Validity measures stated the superiority of the portable pH meter, with a reduced dispersion of data and more exact values. Additionally, correlation analysis demonstrate that the pH values obtained with the pH meter were the closest to the buffers' real pH values.
CONCLUSION
The detailed comparative study presented here reveal the superiority of a portable pH meter to several of the most used dipstick brands in the clinic.Lit-Control® pH Meter represents a reliable alternative when a monitoring of urinary pH is needed, as may happen during the screening of diseases or treatment monitoringin the clinic, as well as during the self-monitoringby the patient under professional supervision at home.
Topics: Employment; Humans; Hydrogen-Ion Concentration; Reagent Strips; Urinalysis
PubMed: 32633250
DOI: No ID Found -
BMC Pediatrics Aug 2020There is a need for an easy and sensitive method for screening of urinary tract infections in young children. We set out to test whether a novel diaper-embedded urine...
BACKGROUND
There is a need for an easy and sensitive method for screening of urinary tract infections in young children. We set out to test whether a novel diaper-embedded urine test device is feasible and reliable in screening for urinary tract infections.
METHODS
This prospective cohort study consisted of young children examined due to a suspected acute urinary tract infection at the Pediatric Emergency Department of the Oulu University Hospital, Finland. We analyzed the same urine samples using three different methods: 1) a diaper-embedded test device applied to the urine pad within the diaper, 2) a urine sample aspirated from the urine pad for the conventional point-of-care dipstick test, and 3) a urine sample aspirated from the urine pad and analyzed in the laboratory with an automated urine chemistry analyzer. The gold standard for confirming urinary tract infection was quantitative bacterial culture.
RESULTS
Urine samples were available from 565 children. Bacterial culture confirmed urinary tract infection in 143 children. Sensitivity of the positive leukocyte screening of the diaper-embedded urine test device was 93.1% (95% CI: 87.4-96.8) and that of the point-of-care urine dipstick analysis was 95.4% (90.3-98.3) in those with both tests results available (n = 528). The sensitivity of the positive leukocyte test of the diaper-embedded test device was 91.4% (85.4-95.5) and that of the automated analysis was 88.5% (82.0-93.3) in those with both tests available (n = 547). The time to the test result after urination was immediate for the diaper-embedded test, 1-5 min for point-of-care dipstick, and 30-60 min for laboratory-based automated urine chemistry analyzer.
CONCLUSIONS
In this prospective study, the diaper-embedded urine test device was an easy and sensitive screening method for UTIs in young children. The main clinical benefit of the diaper-embedded urine test device was that the screening test result was available immediately after urination.
Topics: Child; Child, Preschool; Cohort Studies; Finland; Humans; Prospective Studies; Sensitivity and Specificity; Urinalysis; Urinary Tract Infections
PubMed: 32781982
DOI: 10.1186/s12887-020-02277-5 -
Lab on a Chip Feb 2019Influenza is a viral respiratory tract infection responsible for up to 5 million cases of severe infection and nearly 600 000 deaths worldwide each year. While...
Influenza is a viral respiratory tract infection responsible for up to 5 million cases of severe infection and nearly 600 000 deaths worldwide each year. While treatments for influenza exist, diagnostics for the virus at the point of care are limited in their sensitivity and ability to differentiate between subtypes. We have developed an integrated two-dimensional paper network (2DPN) for the detection of the influenza virus by the surface glycoprotein, hemagglutinin. The hemagglutinin assay was developed using proteins computationally designed to bind with high affinity to the highly-conserved sialic acid binding site. The integrated 2DPN uses a novel geometry that allows automated introduction of an enzymatic amplification reagent directly to the detection zone. This assay was integrated into a prototype device and demonstrated successful detection of clinically relevant virus concentrations spiked into 70 μL of virus-free pediatric nasal swab samples. Using this novel geometry, we found improved assay performance on the device (compared to a manually-operated dipstick method), with a sensitivity of 4.45 × 102 TCID50 per mL on device.
Topics: Hemagglutinin Glycoproteins, Influenza Virus; Humans; Influenza, Human; Molecular Diagnostic Techniques; Paper; Point-of-Care Systems
PubMed: 30724293
DOI: 10.1039/c8lc00691a -
Drug Testing and Analysis Sep 2019Dihydroartemisinin (DHA) and piperaquine (PPQ) are two drugs used in an artemisinin-based combination therapy (ACT). The circulation of counterfeit antimalarial drugs...
Dihydroartemisinin (DHA) and piperaquine (PPQ) are two drugs used in an artemisinin-based combination therapy (ACT). The circulation of counterfeit antimalarial drugs demands the development of simple, point-of-care (POC) tests for monitoring drug quality. Here we aimed to design an antibody-based lateral flow dipstick assay for simultaneous quality control of DHA and PPQ. To obtain a monoclonal antibody (mAb) for PPQ, one structural unit of the symmetric PPQ molecule was used to derive a carboxylic acid for linkage to a carrier protein as immunogen. Screening of hybridoma cells identified an mAb 4D112B2 that reacted with the PPQ-based immunogen. A highly-sensitive icELISA was designed based on this mAb, which showed 50% inhibition concentration of PPQ at 1.66 ng/mL and a working range of 0.35 - 7.40 ng/mL. The mAb showed 10.2, 15.9 and 30.4% cross reactivity to hydroxychloroquine sulfate, chloroquine and amodiaquine, respectively. No cross reactivity was observed to lumefantrine, mefloquine artemisinin and its derivatives. Using our previous DHA dipstick design, a lateral flow dipstick for simultaneous analysis of PPQ and DHA was developed. The indicator ranges for PPQ and DHA were 2 - 5 μg/mL and 250 - 500 ng/mL, respectively. The dipstick was used to semi-quantitatively analyze PPQ and DHA content in commercial ACT drugs, which produced agreeable results to those determined by high-performance liquid chromatography. This combination dipstick makes it a potential POC device for quality control of the two active ingredients in a commonly used ACT.
Topics: Animals; Antibodies, Monoclonal; Antimalarials; Artemisinins; Drug Combinations; Drug Monitoring; Enzyme-Linked Immunosorbent Assay; Equipment Design; Mice; Point-of-Care Systems; Quinolines; Reagent Strips
PubMed: 31150570
DOI: 10.1002/dta.2656