Changing the diagnostic paradigm for sugarcane: development of a mill-based diagnostic for ratoon stunting disease in crude cane juice.

The availability of efficient diagnostic methods is crucial to monitor the incidence of crop diseases and implement effective management strategies. One of the most important elements in diagnostics, especially in large acreage crops, is the sampling strategy as hundreds of thousands of individual plants can grow in a single farm, making it difficult to assess disease incidence in field surveys. This problem is compounded when there are no external disease symptoms, as in the case for the ratoon stunting disease (RSD) in sugarcane. We have developed an alternative approach of disease surveillance by using the crude cane juice expressed at the sugar factory (mill). For this purpose, we optimized DNA extraction and amplification conditions for the bacterium Leifsonia xyli subsp xyli, the causal agent of RSD. The use of nucleic acid dipsticks and LAMP isothermal amplification allows to perform the assays at the mills, even in the absence of molecular biology laboratories. Our method has been validated using the qPCR industry standard and shows higher sensitivity. This approach circumvents sampling limitations, providing RSD incidence evaluation on commercial crops and facilitating disease mapping across growing regions. There is also potential is to extend the technology to other sugarcane diseases as well as other processed crops.

Application of analytical performance specifications for urine test strip methods: Importance of reflectance signals.

INTRODUCTION: Urinalysis is essential for diagnosing kidney-related medical conditions. Urine test strip analysis serves as an initial and efficient screening method for reflex testing with accurate quantitative methods. MATERIALS AND METHODS: Freshly voided urines (n = 206) were analysed using two urine test strip brands on UC-MAX (Menarini) and cobas u 601 (Roche Diagnostics) instruments. Ordinal scale categories and reflectance signals (if available) were both used for the comparison with reference quantitative methods for glucose, proteins and albumin (cobas 503). Samples were considered positive when glucose > 15 or ≥ 54 mg/dL, proteins ≥ 200 mg/L and albumin ≥ 10 mg/L. Optimized reflectance thresholds were calculated by ROC curve analysis. Analytical performance specifications (APS) for trueness of test strip were gathered from the EFLM guideline (FPD, FNG, FNC). RESULTS: Reflectance signals were significantly lower in urine samples considered positive by the reference method (p < 0.0001). Reflectance signals were also correlated with quantitative measurements, showing strong correlation (0.754 to 0.969). Only the use of optimized reflectance thresholds on cobas u 601 achieved at least the minimum EFLM APS (FPD < 20%, FNG < 50% and FNC < 10%). CONCLUSION: The use of reflectance signals from urine test strips enhanced accuracy for glucose, proteins, and albumin measurement and may contribute to improve diagnosis of diverse kidney-related conditions.

Paper-based biosensors as point-of-care diagnostic devices for the detection of cancers: a review of innovative techniques and clinical applications.

The development and rapid progression of cancer are major social problems. Medical diagnostic techniques and smooth clinical care of cancer are new necessities that must be supported by innovative diagnostic methods and technologies. Current molecular diagnostic tools based on the detection of blood protein markers are the most common tools for cancer diagnosis. Biosensors have already proven to be a cost-effective and accessible diagnostic tool that can be used where conventional laboratory methods are not readily available. Paper-based biosensors offer a new look at the world of analytical techniques by overcoming limitations through the creation of a simple device with significant advantages such as adaptability, biocompatibility, biodegradability, ease of use, large surface-to-volume ratio, and cost-effectiveness. In this review, we covered the characteristics of exosomes and their role in tumor growth and clinical diagnosis, followed by a discussion of various paper-based biosensors for exosome detection, such as dipsticks, lateral flow assays (LFA), and microfluidic paper-based devices (µPADs). We also discussed the various clinical studies on paper-based biosensors for exosome detection.

Rapid and Sensitive Detection of Streptococcus iniae in Trachinotus ovatus Based on Multienzyme Isothermal Rapid Amplification.

Infectious diseases caused by Streptococcus iniae lead to massive death of fish, compose a serious threat to the global aquaculture industry, and constitute a risk to humans who deal with raw fish. In order to realize the early diagnosis of S. iniae, and control the outbreak and spread of disease, it is of great significance to establish fast, sensitive, and convenient detection methods for S. iniae. In the present study, two methods of real-time MIRA (multienzyme isothermal rapid amplification, MIRA) and MIRA-LFD (combining MIRA with lateral flow dipsticks (LFD)) for the simA gene of S. iniae were established, which could complete amplification at a constant temperature of 42 °C within 20 min. Real-time MIRA and MIRA-LFD assays showed high sensitivity (97 fg/µL or 7.6 × 102 CFU/mL), which were consistent with the sensitivity of real-time PCR and 10 times higher than that of PCR with strong specificity, repeatability simplicity, and rapidity for S. iniae originating from Trachinotus ovatus. In summary, real-time MIRA and MIRA-LFD provide effective ways for early diagnosis of S. iniae in aquaculture, especially for units in poor conditions.

Integrating filter paper extraction, isothermal amplification, and lateral flow dipstick methods to detect Streptococcus agalactiae in milk within 15 min.

Introduction: Mastitis is one of the most serious diseases affecting dairy farming, causing huge economic losses worldwide. Streptococcus agalactiae is the main pathogenic bacterium of contagious mastitis and can deliver a devastating blow to a farm's economy. Rapid detection is the key to disease control. Methods: In this study, a rapid detection method for S. agalactiae was established. This method combines filter paper extraction, multienzyme isothermal rapid amplification (MIRA), and lateral flow dipsticks (LFD). To simplify the extraction procedure, we designed a disposable extraction device (DED). First, DED performance was evaluated by polymerase chain reaction (PCR) and then the lysis formula and extraction time were optimized. Second, this study compared the extraction performance of a filter paper and an automatic nucleic acid extraction instrument. After screening primers, MIRA for S. agalactiae was established and combined with LFD. Specificity and sensitivity were evaluated after optimizing the reaction conditions. Results: The results showed that the lowest extraction line for DED was 0.01-0.001 ng/µl. In the specificity study, 12 different bacteria were tested, and only S. agalactiae was found to be positive. In the sensitivity study, seven dilution gradients were established, and the lowest detection line was 3.52 × 102 CFU/ml. Discussion: In summary, the method established in this study does not require laboratory equipment and is suitable for on-site detection. The entire method takes only 15 min, is low in cost, has high precision and low technical requirements for operators, which is in contrast with the high cost and cumbersome operation of traditional methods, and is suitable for on-site testing in areas with limited facilities.

Dipstick-based rapid nucleic acids purification and CRISPR/Cas12a-mediated isothermal amplification for visual detection of African swine fever virus.

African swine fever virus (ASFV) can cause highly contagious and fatal disease among domestic pigs, resulting in considerable economic losses for swine breeders. There is a strong demand for accurate, rapid, and simple detection methods especially for on-site application. Nucleic acid testing is the most commonly used method for ASFVdetection. However, traditional nucleic acid purification step is time- and labor-consuming. The nucleic acid purification, amplification and amplicons detection rely on laboratory settings which limits the on-site detection. Here, we proposed a simple and cost-effective detection method that utilized filter paper to purify nucleic acids from swine blood and employed CRISPR/Cas12a-mediated loop-mediated isothermal amplification (LAMP) reaction to detect ASFV. The filter paper which was made into dipsticks could effectively purify nucleic acids from whole blood in 2 min. This simple and low-cost purification method avoided multiple pipetting steps and potential amplification inhibitors (e.g., ethanol) that were generally used in traditional nucleic acids extraction processes. After nucleic acid purification, the lyophilized LAMP reagent dissolved by elution solution was employed to perform isothermal amplification reaction on a portable heating block. The CRISPR/Cas12a system was designed to specifically detect amplicons. Assisted by a portable homemade device, the fluorescent signals produced by positive samples could be observed by the naked eye, while negative samples remained colorless. The whole detection procedure could be finished within 50 min with a detection limit of one copies/µL. This established method provided a novel strategy for rapid visualized detection and showed great potential for on-site application.

Paper based micro/nanofluidics devices for biomedical applications.

This chapter details the significance, fabrication and biomedical applications of paper-based microfluidic devices. The first part of the chapter describes the importance of paper diagnostic devices, highlighting pretreatment, dipsticks, lateral flow assays, and microPADs. Various methods followed for the fabrication of the paper analytical devices are discussed in the second part. The last part is about some of the important biomedical applications of paper analytical devices. Finally, the challenges and research gaps in the paper microfluidics for biomedical applications are presented.

Revisiting approaches to and considerations for urinalysis and urine culture reflexive testing.

Urinalysis is considered the world's oldest laboratory test. Today, many laboratories use macroscopic urinalysis as a screening tool to determine when to subject urine samples for a microscopic urinalysis and/or bacterial culture. While reflexive urine microscopy has been practiced for decades, and reflexive urine culture, more recently, evidence-based guidelines regarding optimal reflexive criteria and workflows are lacking. Standard approaches are hindered, in part, by a lack of harmonization of urinalysis and urine culture practices, heterogeneity in patient populations that are studied, and lack of provider adherence to recommended practices. This review summarizes studies that have evaluated the performance of reflexive urine microscopy and reflexive urine culture, particularly in the context of urinary tract infections. It also examines reported clinical outcomes from reflexive urinalysis interventions and their impact on antibiotic stewardship efforts. Finally, it discusses laboratory operational considerations for the implementation of reflexive algorithms.

Dry Reagent Tests in the 1880s-Dr Pavy's Pellets and Dr Oliver's Papers.

BACKGROUND: In the 1880s, concern over the inconvenience of hazardous chemical solutions used for bedside urinalysis sparked an interest in the development of dry reagents for a range of common urine tests. CONTENT: This article examines the history of Dr Pavy's Pellets and Dr Oliver's Papers, 2 different dry reagent systems developed in the 1880s for bedside urine testing. It sets these developments in the context of the earlier dry chemistry work (e.g., indicator papers) and the subsequent work that led to modern day reagent tablets and dipstick devices. SUMMARY: Tests based on dry reagents can be traced back to the 1st century, but active development, in the form of indicator papers, dates from the 1600s. In the 1880s, spurred by dissatisfaction with liquid-based bedside urine testing among clinicians, Dr Frederick William Pavy and Dr George Oliver developed dry reagent tests, based on pellets (Dr Pavy's Pellets) and chemically impregnated papers (Dr Oliver's Papers) for urine sugar and urine albumin. These reagents were commercialized by a number of companies and provided in convenient cases (Physician's Pocket Reagent Case). Eventually, these tests lost popularity and were replaced by the type of tablets and dipsticks developed by both Eli Lilly, and the Ames Division of Miles Laboratories (subsequently Bayer, and currently Siemens Healthineers) during the 1940s and 1950s.

Storage of urine specimens in point of care (POC) urine drug testing cups reduces concentrations of many drugs.

BACKGROUND: Many clinical toxicology laboratories receive urine specimens in urine cups that contain point of care (POC) drug testing strips. We conducted this study to evaluate the effect on the stability of commonly measured drugs in the clinical toxicology laboratory when urine is exposed to POC urine drug testing cups. METHODS: Drug free urine was spiked with 85 drugs that were measured by a validated liquid chromatography mass spectrometry (LCMS) method after exposure to POC urine drug testing cups at ambient and 2-6 °C temperatures. Alterations ≥20% were defined as significant changes in the drugs concentration. RESULTS: Concentrations of amitriptyline, cyclobenzaprine, fentanyl, fluoxetine, flunitrazepam, nortriptyline, paroxetine, and sertraline were significantly reduced when urine specimens were stored inside POC urine drug testing cups for 24 h at ambient temperature. Storage of urine in urine chemistry dipsticks reduced the concentration of several drugs. When spiked urine was exposed to an increasing number of POC urine drug testing strips, the concentrations of some drugs were reduced in a dose-dependent manner. The drugs that were absorbed by POC urine drug testing strips were partially back extracted from the strips. CONCLUSION: Exposure of urine specimens to POC urine drug testing strips reduces the concentration of several drugs measured by LCMS method.

Sensitive and rapid visual detection of Salmonella Typhimurium in milk based on recombinase polymerase amplification with lateral flow dipsticks.

Salmonella Typhimurium (S. Typhimurium) can cause serious foodborne diseases. In this study, an assay combining recombinase polymerase amplification (RPA) with lateral flow dipsticks (LFD) was developed to detect S. Typhimurium in milk. The RPA forward primers STF1, STF2, STF3, the reverse primer STR labeled with digoxin, and the probe STProb labeled with FAM were designed and screened to produce RPA products for LFD detection. The RPA reaction volume, temperature, and time were then optimized, and the sensitivity and specificity of the developed method were analyzed. Finally, the RPA-LFD method was evaluated using milk artificially contaminated with S. Typhimurium. Results indicated that the primer pair STF1/STR is the optimal combination for detecting the bacterium. The minimum volume, shortest time, and optimal temperature of the RPA reaction were 10 µL, 10 min, and 40-42 °C, respectively. The limit of detection of RPA-LFD for detecting the genomic DNA of S. Typhimurium was 1 fg, which is 5 and 10 times lower than the corresponding limits of RPA-agarose gel electrophoresis (AGE) and PCR-AGE, respectively. Testing with 29 other foodborne bacteria as controls revealed that RPA-LFD was highly specific for S. Typhimurium. RPA-LFD can detect S. Typhimurium at concentrations as low as 1.95 CFU/mL in artificially inoculated milk samples and is thus 10 times more sensitive than PCR. Hence, the RPA-LFD assay established in this study could be a potential point-of-care/need test for S. Typhimurium, especially in areas with limited resources.

Analytical verification of 12 most commonly used urine dipsticks in Croatia: comparability, repeatability and accuracy.

INTRODUCTION: Variability among manufacturers of urine dipsticks, respective to their accuracy and measurement range, may lead to diagnostic errors and thus create a serious risk for the patient. Our aims were to determine the level of agreement between 12 most commonly used urine dipsticks in Croatia, examine their accuracy for glucose and total protein and to test their repeatability. MATERIALS AND METHODS: A total of 75 urine samples were used to examine comparability and accuracy of 12 dipstick brands (Combur 10 TestM, ChoiceLine 10, Combur 10 TestUX, ComboStik 10M, ComboStik 11M, CombiScreen 11SYS, CombiScreen 10SL, Combina 13, Combina 11S, Combina 10M, UriGnost 11, Multistix 10SG). Agreement between each dipstick and the reference (Combur 10 TestM) was expressed as kappa coefficient (acceptable κ ≥ 0.80). Accuracy for glucose and total protein was tested by comparison with quantitative measurements on analysers: AU400 (Beckman Coulter, USA), Cobas 6000 c501 (Roche Diagnostics, Germany) and Architect plus c4000 (Abbott, USA). Repeatability was assessed on 20 replicates (acceptable > 90%). RESULTS: Best agreement was achieved for glucose, total protein and nitrite (11/11, k > 0.80) and the lowest for bilirubin (5/5, k < 0.60). Sensitivities for total protein were 41-75% (AU400) and 56-92% (Cobas and Architect); while specificities were 41-75% (AU400, Cobas, Architect). Dipsticks' sensitivity and specificity for glucose were 68-98%. Most of the dipsticks showed unacceptable repeatability (6/12, < 90%) for one parameter, most prominently for pH (3/12, < 90%). CONCLUSIONS: Most commonly used dipsticks in Croatia showed low level of agreement between each other. Moreover, their repeatability varies among manufacturers and their accuracy for glucose and proteins is poor.

Biomphalaria pfeifferi Snails and Intestinal Schistosomiasis, Lake Malawi, Africa, 2017-2018.

Two surveys conducted in 2017 and 2018 demonstrated Biomphalaria pfeifferi snails in Lake Malawi in Africa. Epidemiologic examination of 175 local children at 3 primary schools confirmed emergence of intestinal schistosomiasis. These findings highlight autochthonous transmission of Schistosoma mansoni flukes in Lake Malawi and the need to revise international travel advice.

Isothermal DNA amplification combined with lateral flow dipsticks for detection of biothreat agents.

The recently developed methods of nucleic acids isothermal amplification are promising tools for point-of-care diagnostics and in the field detection of pathogenic microorganisms. However, application of these methods outside a laboratory faces some challenges such as the rapid and sensitive detection of amplified products and the absence of cross-reactivity with genetically related microorganisms. In the presented study we compared three methods of isothermal DNA amplification loop-mediated isothermal amplification (LAMP), recombinase polymerase amplification (RPA) and thermophilic helicase-dependent isothermal DNA amplification (tHDA), for detection of highly dangerous pathogens, such as Bacillus anthracis, Francisella tularensis and Yersinia pestis, and combined them with lateral flow dipsticks for the rapid visualization of amplified products. We observed low specificity of the three methods for B. antharcis, medium for Y. pestis and high for F. tularensis detection. Sensitivity and the detection limit were high and comparable for all the methods. We concluded that the lateral flow dipsticks have been a very useful tool for product detection of the isothermal amplification methods and enable reading the results without the use of any equipment. However, our results showed that the use of isothermal amplification methods is strongly related to the risk of false positive results.

Open label feasibility study evaluating D-mannose combined with home-based monitoring of suspected urinary tract infections in patients with multiple sclerosis.

OBJECTIVE: To assess the feasibility of using D-mannose, a natural food supplement, in patients with multiple sclerosis (MS) reporting recurrent urinary tract infections (UTIs) as a preventative. METHODS: A single-center, open-label, feasibility study enrolled patients with MS, using and not using urinary catheters, experiencing recurrent UTIs (≥3/year or ≥2/6 months). Participants were given D-mannose powder 1.5 grams twice daily for 16-weeks and were instructed to monitor suspected UTIs at home using urine dipsticks. Diaries were used to record compliance, number of prescriptions of antibiotics received for UTIs, results of urine dipsticks and cultures. RESULTS: Overall, 22 patients with MS, median age 50 years (46-59) were enrolled: 10 were not using catheters and 12 were using catheters. The compliance rates for using D-mannose and dipsticks for testing suspected UTIs were 100% and 90.2%, respectively. Sixty-one episodes of suspected UTIs were recorded, 19/61 (31.1%) were confirmed UTIs and 29/61 (47.5%) prescriptions of antibiotics were made. The number of monthly proven UTIs decreased both in catheter users and non-users (P < 0.01). No adverse effects were reported. CONCLUSION: Using D-mannose in patients with MS experiencing recurrent UTIs and self-monitoring for infections is feasible and safe. Further studies are required to establish efficacy. CinicalTrials.gov (identifier NCT02490046).

Análisis de orina: estandarización y control de calidad / Urine analysis: standardization and quality control / Análise de urina: padronização e controle de qualidade

El examen de orina completa data de los tiempos de Hipócrates. En la actualidad se basa en la utilización de tiras reactivas y la visualización al microscopio, careciendo de una estandarización actualizada y control de calidad. En el presente trabajo se realizó un estudio comparativo entre observadores, estandarizando el proceso y elaborando una solución control junto con una colección fotográfica del sedimento para enseñanza, entrenamiento y control interno. Se evaluaron 200 muestras de orinas de pacientes al azar. Los parámetros fisicoquímicos se determinaron en un equipo Urisys 2400 (Roche). El análisis microscópico fue realizado por dos operadores experimentados. Se preparó una solución control positiva de los parámetros usuales de tiras reactivas. Los resultados fueron analizados mediante el test Kappa, p<0,05. La correlación entre observadores, utilizando el procedimiento propuesto, fue siempre mayor que con el proceso de rutina. La solución control fue estable durante los 4 meses que duró la experiencia, dando positivas las determinaciones de glucosa, proteínas, hemoglobina, cetonuria y leucocitos, manteniéndose el valor de pH y de densidad. Se concluye que con la estandarización se logró aumentar el grado de correlación entre observadores, por lo tanto se propone el uso de esta metodología para uniformar criterios; además, la preparación de la sustancia control y de una colección fotográfica permitió controlar el procedimiento de una forma más económica sin dejar de lado la confiabilidad.

Urine analysis is one of the most ancient tests. It dates back from Hyppocrates times. Nowadays it is based on the use of reactive dipsticks and visual examinations in the microscope, with no quality control or adjusted standardization. In the present work, a standardized procedure, a positive control solution for dipsticks and a photographic collection of urine sediment were performed for teaching, training and control of the laboratory staff. Urisys 2400 (ROCHE) was used to analyze 200 samples randomly. The microscopic analysis was made by two experienced operators. A positive control solution of usual parameters of reactive dipsticks was performed. Data analysis was fulfilled by Kappa test p<0.05. The correlation between observers, using the proposed procedure, was always higher than in the routine process. The control solution was stable over the 4-month experience, yielding positive results in glucose, protein, hemoglobin, ketonuria and leukocyte, keeping pH and density values. It can be concluded that with standardization, the degree of correlation between observers was increased, for which reason this methodology is proposed to unify criteria; besides, elaboration of the control substance and a photographic collection makes it possible to control the procedure in a more economic fashion without leaving aside reliability.

O exame de urina completa data dos tempos de Hipócrates. Atualmente é baseado no uso de tiras-teste e a visualização no microscópio, carecendo de uma padronização atualizada e controle de qualidade. No presente trabalho foi realizado um estudo comparativo entre observadores padronizando o processo e elaborando uma solução de controle juntamente com uma coleção de fotografias do sedimento para ensino, treinamento e controle interno. 200 amostras de urinas de pacientes selecionados aleatoriamente foram avaliadas. Os parâmetros físico-químicos foram determinados em um equipamento Urisys 2400 (Roche). A análise microscópica foi realizada por dois operadores experientes. Foi realizada uma solução controle positiva dos parâmetros usuais de tiras-teste. Os resultados foram analisados através do teste Kappa, p<0,05. A correlação entre observadores, utilizando o procedimento proposto, foi sempre maior que com o processo de rotina. A solução controle manteve-se estável durante os 4 meses em que foi levada a cabo a experiência, dando positivas as determinações de glicose, proteínas, hemoglobina, cetonúria e leucócitos, mantendo o valor de pH e de densidade. Conclui-se que com a padronização foi possível aumentar o grau de correlação entre observadores, portanto se propõe o uso desta metodologia para uniformizar critérios; além disso, a elaboração da substância controle e de uma coleção fotográfica permite controlar o procedimento de uma maneira mais econômica, sem deixar de lado a confiabilidade.

Análisis de orina: estandarización y control de calidad / Urine analysis: standardization and quality control / Análise de urina: padronizaþÒo e controle de qualidade

El examen de orina completa data de los tiempos de Hipócrates. En la actualidad se basa en la utilización de tiras reactivas y la visualización al microscopio, careciendo de una estandarización actualizada y control de calidad. En el presente trabajo se realizó un estudio comparativo entre observadores, estandarizando el proceso y elaborando una solución control junto con una colección fotográfica del sedimento para enseñanza, entrenamiento y control interno. Se evaluaron 200 muestras de orinas de pacientes al azar. Los parámetros fisicoquímicos se determinaron en un equipo Urisys 2400 (Roche). El análisis microscópico fue realizado por dos operadores experimentados. Se preparó una solución control positiva de los parámetros usuales de tiras reactivas. Los resultados fueron analizados mediante el test Kappa, p<0,05. La correlación entre observadores, utilizando el procedimiento propuesto, fue siempre mayor que con el proceso de rutina. La solución control fue estable durante los 4 meses que duró la experiencia, dando positivas las determinaciones de glucosa, proteínas, hemoglobina, cetonuria y leucocitos, manteniéndose el valor de pH y de densidad. Se concluye que con la estandarización se logró aumentar el grado de correlación entre observadores, por lo tanto se propone el uso de esta metodología para uniformar criterios; además, la preparación de la sustancia control y de una colección fotográfica permitió controlar el procedimiento de una forma más económica sin dejar de lado la confiabilidad.(AU)

Urine analysis is one of the most ancient tests. It dates back from Hyppocrates times. Nowadays it is based on the use of reactive dipsticks and visual examinations in the microscope, with no quality control or adjusted standardization. In the present work, a standardized procedure, a positive control solution for dipsticks and a photographic collection of urine sediment were performed for teaching, training and control of the laboratory staff. Urisys 2400 (ROCHE) was used to analyze 200 samples randomly. The microscopic analysis was made by two experienced operators. A positive control solution of usual parameters of reactive dipsticks was performed. Data analysis was fulfilled by Kappa test p<0.05. The correlation between observers, using the proposed procedure, was always higher than in the routine process. The control solution was stable over the 4-month experience, yielding positive results in glucose, protein, hemoglobin, ketonuria and leukocyte, keeping pH and density values. It can be concluded that with standardization, the degree of correlation between observers was increased, for which reason this methodology is proposed to unify criteria; besides, elaboration of the control substance and a photographic collection makes it possible to control the procedure in a more economic fashion without leaving aside reliability.(AU)

O exame de urina completa data dos tempos de Hipócrates. Atualmente é baseado no uso de tiras-teste e a visualizaþÒo no microscópio, carecendo de uma padronizaþÒo atualizada e controle de qualidade. No presente trabalho foi realizado um estudo comparativo entre observadores padronizando o processo e elaborando uma soluþÒo de controle juntamente com uma coleþÒo de fotografias do sedimento para ensino, treinamento e controle interno. 200 amostras de urinas de pacientes selecionados aleatoriamente foram avaliadas. Os parÔmetros físico-químicos foram determinados em um equipamento Urisys 2400 (Roche). A análise microscópica foi realizada por dois operadores experientes. Foi realizada uma soluþÒo controle positiva dos parÔmetros usuais de tiras-teste. Os resultados foram analisados através do teste Kappa, p<0,05. A correlaþÒo entre observadores, utilizando o procedimento proposto, foi sempre maior que com o processo de rotina. A soluþÒo controle manteve-se estável durante os 4 meses em que foi levada a cabo a experiÛncia, dando positivas as determinaþ§es de glicose, proteínas, hemoglobina, cetonúria e leucócitos, mantendo o valor de pH e de densidade. Conclui-se que com a padronizaþÒo foi possível aumentar o grau de correlaþÒo entre observadores, portanto se prop§e o uso desta metodologia para uniformizar critérios; além disso, a elaboraþÒo da substÔncia controle e de uma coleþÒo fotográfica permite controlar o procedimento de uma maneira mais econ¶mica, sem deixar de lado a confiabilidade.(AU)

Reliability of reagent strips for semi-quantitative measurement of glucosuria in a neonatal intensive care setting.

BACKGROUND: Glucosuria in preterm infants is often measured using a visually readable reagent strip, e.g., when monitoring total parenteral nutrition or during sepsis or when treating with corticosteroids. However, the specific circumstances in a neonatal intensive care unit (NICU), such as the use of diapers and the high temperature in incubators, could affect its reliability. OBJECTIVES: To evaluate the reliability of the semi-quantitative measurement of glucosuria under the specific circumstances of a NICU setting. METHODS: Nine hundred assessments of artificially supplemented (contrived) urine samples, intended to simulate pathological specimens, were performed under the following varying conditions: environmental temperature (21°C and 34°C); different times of contact of the urine with the diaper; and using two different methods of collecting urine from the diaper. Each reagent strip was read independently by three observers. The test strips scores were categorized as 0, 1+, 2+, 3+, or 4+ in ascending degree of glucosuria. RESULTS: Agreement was excellent under all the different conditions (temperature, weighted kappa (κ(w)) = 0.92; method of urine collection, κ(w) = 0.88; time, p = 0.266). Inter-observer reliability was very good (multi-rater κ = 0.81). The deviation between the different conditions was seldom larger than one category (2.9%). The reagent strip readings were concordant with the true urinary glucose concentrations in 79.0% of assessments. The discordance was never larger than one category. CONCLUSION: The reliability of the semi-quantitative measurement of glucosuria in newborn infants using reagent strips is good, even under the conditions of a NICU. Changes in the rating of reagent strips of more than one category are most likely to be beyond measurement error.

Detection of proteinuria in pregnancy: comparison of qualitative tests for proteins and dipsticks with urinary protein creatinine index.

BACKGROUND AND OBJECTIVES: Excretion of urinary protein increases to 300 mg/d (from up to 150 mg/d) in normal pregnancy. Values above this may be due to disorders that can endanger the patient or her pregnancy. Quantitative analysis of 24-hour urine is considered the gold standard for ascertaining daily protein excretion. Routine laboratory tests performed on spot urine samples indicate protein concentration in the particular sample, and can lead to diagnostic error if urine output is less or more than 1L/d. The Protein Creatinine Index (PCI) shows good correlation with 24-hour protein estimation. However, PCI varies with sex and race. We have correlated the results of qualitative estimation procedures and the dipstick values with protein creatinine index. MATERIAL AND METHODS: We measured protein and creatinine in spot urine samples obtained from 57 pregnant and 80 non-pregnant healthy women of 18-36 years, and calculated PCI. We also tested the samples qualitatively for proteins by routine tests and dipsticks. RESULTS: Normal range of PCI in non-pregnant women, determined by a non-parametric method was 30-150. PCI was increased significantly in pregnancy (maximum increase in the third trimester). Amongst the qualitative tests, heat coagulation test gave the lowest percentage of false positives and a slightly higher percentage of false negatives compared to Heller's nitric acid and sulphosalicylic acid tests, and dipsticks. INTERPRETATIONS AND CONCLUSIONS: We conclude that heat coagulation test be used for initial screening, with PCI being performed on all samples testing positive to rule out false positives.