Desempenho de diferentes marcas de tiras reagentes relativo à densidade e à análise química da urina de cães e gatos / Performance of different brands of reagent strips for density and chemical analysis of dog and cat urine

Objetivou-se verificar a compatibilidade entre diferentes marcas de tiras reagentes para urinálise, tanto de uso veterinário, como de uso humano, e confrontar os parâmetros semiquantitativos desse instrumento com métodos quantitativos. Para isso, foram analisadas 77 amostras frescas de urina de cães e gatos e testados 04 modelos de tiras reagentes. Quanto à densidade urinária, houve correlação razoável entre os métodos quantitativo e semiquantitativo naquelas amostras com pH ácido, mas não naquelas com pH neutro ou alcalino. Quanto à concentração proteica, houve similaridade de 53,3% a 83,3% entre as marcas testadas e quando comparadas com a análise fotométrica houve uma correlação razoável (rs = 0,69752 a 0,75074). Em ponto de corte de 15mg/dL de proteína, a sensibilidade da tira reagente foi 82,5% e 100% para urina canina e felina, respectivamente. No tocante à hematúria, houve divergência razoável entre a sedimentoscopia e as diferentes marcas de tiras reativas. Quanto à piúria, há uma baixa sensibilidade das tiras em relação às amostras caninas com muitos resultados falso-negativos (33% a 75%), enquanto em amostras felinas a sensibilidade foi de 100%. Assim, independente da marca, as tiras reagentes devem servir apenas como teste rápido de triagem, sendo mais apropriado o uso de métodos quantitativos na avaliação clínica do paciente a partir da urinálise.

The aim was to verify the compatibility between different brands of urinary dipsticks, for both human and veterinary use, and to compare the semiquantitative parameters of this instrument with quantitative methods. For this, 77 fresh samples of urine from dogs and cats were analyzed e and 04 models of reagent strips were tested. Regarding urinary density, a reasonable correlation was observed between the quantitative and semiquantitative methods in those samples with acidic pH, which did not occur in those with neutral or alkaline pH. Regarding the protein concentration, there was similarity from 53.3% to 83.3% between the brands and in the comparative analysis between the control strip and the photometric analysis, there was a reasonable correlation (rs = 0.69752 to 0.75074). In cut-off point of 15mg/dL protein, the sensitivity of the reagent strip was 82.5% and 100% for canine and feline urine, respectively. Regarding hematuria, there was a reasonable divergence of results between sedimentation and tested dipsticks. As for pyuria, there is a low sensitivity of the strips in relation to canine samples with many false negative results (33% to 75%), while in feline samples the sensitivity was 100%. Thus, regardless of the brands, the reagent strips should serve only as a rapid screening test, while the use of quantitative methods in the clinical evaluation of the patient from urinalysis is more appropriate.

Estimación de la biomasa fúngica en un suelo del sudoeste de la provincia de Buenos Aires (Argentina) con una tinción directa con blanco de calcoflúor / Fungal biomass estimation in soils from southwestern Buenos Aires province (Argentina) using calcofluor white stain

Los microorganismos del suelo son vitales para el correcto funcionamiento de los ecosistemas, principalmente por su papel en el ciclado de nutrientes. La intensificación del uso del suelo y las prácticas agrícolas alteran negativamente la actividad microbiana. La biomasa fúngica es uno de los parámetros más utilizados para estudiar el impacto de las actividades agrícolas en la estructura y el funcionamiento del suelo. El objetivo del presente trabajo fue estimar la biomasa fúngica en un suelo del sudoeste bonaerense con el fin de obtener valores de referencia que permitan usar este parámetro como un indicador de cambios en el ecosistema y, por otro lado, demostrar que la metodología empleada es sensible a las variaciones en las condiciones climáticas. Se colectaron muestras de suelos durante 2 años consecutivos. Se prepararon frotis de suelo y se tiñeron con soluciones de distintas concentraciones de blanco de calcoflúor y luego se estimó la biomasa fúngica observando los frotis con microscopio de epifluorescencia. Los valores de biomasa fúngica estimados variaron entre 2,23 y 26,89 μg Cfúngico/g de suelo y estuvieron dentro del rango esperable para el tipo de suelo estudiado. La biomasa fúngica mostró una relación positiva con la temperatura y las precipitaciones. La metodología empleada resultó ser confiable, repetible y sensible a cambios en las condiciones climáticas. Los resultados podrían usarse como valores de referencia para estudiar la biomasa fúngica de suelos bajo distintas condiciones y emplearse como indicadores del impacto de las distintas prácticas agrícolas sobre el ecosistema.

Soil microorganisms are vital for ecosystem functioning because of the role they play in soil nutrient cycling. Agricultural practices and the intensification of land use have a negative effect on microbial activities and fungal biomass has been widely used as an indicator of soil health. The aim of this study was to analyze fungal biomass in soils from southwestern Buenos Aires province using direct fluorescent staining and to contribute to its use as an indicator of environmental changes in the ecosystem as well as to define its sensitivity to weather conditions. Soil samples were collected during two consecutive years. Soil smears were prepared and stained with two different concentrations of calcofluor, and the fungal biomass was estimated under an epifluorescence microscope. Soil fungal biomass varied between 2.23 and 26.89 μg fungal C/g soil, being these values in the range expected for the studied soil type. The fungal biomass was positively related to temperature and precipitations. The methodology used was reliable, standardized and sensitive to weather conditions. The results of this study contribute information to evaluate fungal biomass in different soil types and support its use as an indicator of soil health for analyzing the impact of different agricultural practices.

Evaluación de las características funcionales del juego de reactivos VDRL Plus / Evaluation of the functional characteristics of the set of reagents called VDRL Plus

Introducción: la prueba de VDRL (venereal disease research laboratories) es una técnica no treponémica de microfloculación en lámina para la detección cualitativa y semicuantitativa de reaginas plasmáticas. El VDRL Plus es un juego de reactivos que contiene una suspensión antigénica estabilizada (no alcohólica), basada en una mezcla de cardiolipina, colesterol y lecitina en tampón fosfato. Objetivo: determinar un conjunto de parámetros funcionales que caracterizan el desempeño diagnóstico o clínico del juego de reactivo VDRL Plus producido en Centro de Isótopos (CENTIS). Métodos: los parámetros del desempeño diagnóstico evaluados fueron: sensibilidad y especificidad diagnóstica, valores predictivos positivo y negativo, razón de verosimilitud positiva y negativa. Se determinaron además los índices de Youden y de concordancia Kappa. Se emplearon como métodos de referencia TPHA (Treponema pallidum hemagglutination) y RPR (rapid plasma reagin)-carbón producidos en el CENTIS. Se utilizaron muestras de sueros obtenidas en diferentes instituciones de salud de La Habana y el estudio se realizó con dos lotes del producto. Resultados: para los dos lotes evaluados se obtuvieron valores de sensibilidad de 100 porciento y de especificidad diagnóstica de 81 y 84 porciento. Los valores predictivos positivos resultaron de 71 y 75 porciento, y los negativos de 100 porciento. Por su parte, las razones de verosimilitud negativas fueron de 0 porciento y las positivas de 5,3 y 6,3 porciento, para cada lote estudiado. Los índices de Youden obtenidos (0,84 y 0,81) y la concordancia expresada mediante Kappa muestran que existe una adecuada correlación entre los resultados con el método en evaluación y los de referencia. Conclusiones: las características funcionales evaluadas evidencian que el diagnosticador VDRL Plus es apto para el uso previsto y que estas son consistentes entre los lotes estudiados

Introduction: the VDRL test (venereal disease research laboratories) is a no-treponemal slide microaglutination test for the qualitative and semi-quantitative detection of plasma reagins in human serum. The VDRL Plus contains non alcoholic stabilized antigen suspension based in cardiolipin, lecithin and cholesterol in phosphate buffer. Objective: to determine a group of functional parameters in the diagnostic or clinical performance of the VDRL Plus set of reagents produced by the Center of Isotopes (CENTIS). Methods: several parameters, such as, sensitivity, specificity, positive and negative predictive values and positive and negative likelihood ratios were evaluated. Likewised, Youden and Kappa indexes were calculated. Two references methods were employed, that is, TPHA (Treponema pallidum hemagglutination) and RPR-Carbon (rapid plasma reagin)-carbon, both from CENTIS. Serum samples were collected from several health centers in Havana city. Two different product batches were evaluated. Results: the sensitivity value for both evaluated batches was 100 percent and the specificity was 81 and 84 percent. The positives predictive values were 71 and 75 percent and negative predictive value was 100 percent. The positive likelihood ration were 5.3 and 6,3 percent respectively and negative likelihood ration was 0 percent for both batches. The Youden indexes obtained (0.84 and 0.81) and Kappa's indexes showed that there was an adequate correlation between the results obtained and the evaluation and reference methods. Conclusions: the evaluated functional characteristics showed that they are consistent among studied batches and that the VDRL Plus assay is suitable for the intended use

Um método simplificado para análise de cotinina em urina usando CG-EM / A simplified method for the analysis of urinary cotinine by GC-MS

Cotinine is the major metabolite of nicotine and, being very stable and having a long biological half-life, it can be used as a biomarker for tobacco exposure. The aim of this study was to develop an analytical GC-MS technique to measure levels of cotinine in the urine of active and passive smokers and to compare the results with reference values. The extraction of cotinine to generate the calibration curve was performed by mixing urine (250 ?L) with 50 ?L of a cotinine standard, 50 ?L of an internal standard of deuterated cotinine (15μgμmL-1) and 50 μL of 10% NH4OH solution. Next, 2 mL of a mixture of MTBE:dichloromethane:ethyl acetate (30:30:40 by volume) was added and the whole was vortexed, then centrifuged at 3000 rpm. Finally, 1.6 mL of the organic layer was evaporated under a stream of dry air at 50 °C. The resulting extract was dissolved in methanol and injected into the GC-MS system. The LOQ and LOD for cotinine were 100 and 20 ng.mL-1, respectively. The curve was linear over the whole tested range of 100 - 5000 ng.mL-1 and the method achieved 50% recovery. The intra and inter-day precisions were 1.62 ? 7.28% and 0.86 - 2.68%, respectively. Accuracy was determined at three concentrations (low, medium and high), with six replicates (95.24- 97.67%). The validation of this cotinine assay by GC-MS showed that it exhibited satisfactory limits and the assay could be performed with a one-step liquid-liquid extraction. The technique presented here can thus be used for the quantitation of cotinine levels in the urine of passive and active smokers.

A cotinina é o metabólito principal da nicotina, é muito estável e tem uma elevada meia-vida biológica e pode ser usado como biomarcador da exposição ao tabaco. O objetivo deste estudo foi desenvolver uma técnica analítica em CG-EM para medir os níveis de cotinina na urina de fumantes ativos e passivos e comparar os resultados com valores de referência. A extração da cotinina para construir a curva de calibração foi desenvolvida misturando 250 μL de padrão de cotinina em urina, 50 μL de padrão interno (cotinina deuterada 15 ?g?mL-1) e 50 μL de solução aquosa de NH4OH 10%. Em seguida, 2 mL da mistura MTBE:diclorometano:acetato de etila (30:30:40 v/v) foi adicionada, agitada em vórtex e centrifugada a 3000 rpm. Finalmente, 1,6 mL da camada orgânica foi evaporada sob ar seco a 50 °C. O extrato resultante foi dissolvido em metanol e injetado no sistema CG-EM. Os limites de quantificação e de detecção foram 100 e 20 ng?mL-1, respectivamente. A curva de calibração foi linear no intervalo de concentração testado (100 - 5000 ng?mL-1), com 50% de recuperação. Os valores de precisão intra-dia e inter-dia foram 1,62 ? 7,28% e 0,86 - 2,68%, respectivamente. A exatidão (95,24 - 97,67%) foi determinada sob 3 concentrações (baixa, média e alta), com 6 replicatas. A validação deste procedimento para análise de cotinina por CG-EM demonstrou valores satisfatórios, numa única etapa de extração líquido-líquido, podendo ser utilizada para a quantificação dos níveis de cotinina em amostras de urina de fumantes ativos e passivos.

Application of HIV-1-green fluorescent protein (GFP) reporter viruses in neutralizing antibody assays.

We made reporter HIV-1 DNA constructs carrying green fluorescent protein (GFP) gene and exchangeable env of subtype E. The recombinant constructs were used to produce infectious reporter viruses, which induced infected cells to emit green fluorescent light and rendered them easily detectable at single cell level. Because the env in this construct can be easily exchanged, viruses with different antigenic epitopes can be made. We used these reporter viruses to set up a neutralizing antibody assay based on fluorescence reduction by flow cytometric measurement. The result of this new assay correlated with the standard infectivity reduction assay using primary isolates. Because this new assay is faster and much less costly than the standard assay using a p24 endpoint and can be performed in peripheral blood mononuclear cells (PBMC), it provides a useful tool for analysis of HIV-1 immune responses.

Rapigluco-test. Resultados de la evaluación externa y pruebas de terreno / RapiGluco-Test. Results of the external evaluation and field tests

Se evaluó el RapiGluco-Test en el Centro Nacional de Referencia para el Laboratorio Clínico. El intervalo de linealidad resultó satisfactorio entre 2,5 y 22 mmol/L de glucosa y la recuperación del método fue del 90 porciento. En el estudio de exactitud, tanto para los lotes experimentales como para los de escalado, se encontró buena correlación con los métodos de referencia utilizados. La precisión evaluada a 2 niveles de concentración fue buena. Se distribuyeron 49 lotes del reactivo en hospitales y policlínicos de todo el país y se realizaron 1 818 000 determinaciones de glucosa entre 1993 y 1996. No se presentaron quejas en relación con el comportamiento del producto

Modificación de un método para colinesterasa plasmática empleando la reducción del ferricianuro como indicador / Modification in the method for serum cholinesterase in ferricyanide reduction how indicatory

Se describe la modificación de un método para la cuantificación de colinesterasa plasmática mediante monitoreo continuo empleando ferricianuro como indicador. La tiocolina liberada de la propioniltiocolina reduce el ferricianuro a ferrocianuro y la disminición de absorbancia a 405 nm es proporcional a la actividad de la enzima. Las precisiones día a día para muestras con valores de colinesterasa bajos y altos mostraron coeficientes de variación de 3,2 y 1,2 por ciento y en un mismo día de 1,1 y 0,52 por ciento respectivamente. La bilirrubina no presenta una interferencia importante y cada 50mg/dL de hemoglobina producen una interferencia de -4 por ciento. El reactivo de ferricianuro almacenado en botella ámbar es estable por al menos 3 meses a temperatura ambiente y 6 meses a 4-8 §C. Al comparar los resultados con un método que emplea la reacción de Ellman se obtuvo una ecuación de regresión lineal de Y = 1,22 (X) - 732, con un coeficiente de correlación (r) de 0,988 y una desviación estándar sobre la línea de regresión (Sy/x) de 378 U/L. (Rev Cost Cienc Med 1999; 20(1,2): 17-27) PALABRAS CLAVE: Colinesterasa sérica, organofosfatos, carbamatos, pesticidas, métodos colorimétrico, toxicología

Frequency of 2, 3, 5-triphenyltetrazolium chloride (TTC) non-reducing bacteria in pasteurized milk

2, 3, 5-triphenyltetrazolium chloride (TTC) is a dye largely used for enumeration of microbial colonies in solid culture media, being a key component of the dry rehydratable film system used for microbiological analysis of food. This dye is colorless in the oxidized form and red when reduced by microorganisms, due to formation of formazan. In this study, TTC was added to Plate Count Agar (PCA) for enumeration of microorganisms in thirty four pasteurized milk samples, with the aim to verify the frequency of microorganisms that are unable to reduce TTC. Milk samples were decimally diluted in saline and pour-plated in PCA plus 0.015(per cent) TTC. Colonies were counted after 24h and 48 h of incubation at 35(degree)C. From a total of 50,574 colonies 19,665(38.88 per cent) did not reduce TTC in 48h. It was observed that 571(6.36 per cent) colonies that were colorless in 24h became red in 48h. From those that didn't reduce TTC in 48h, 233 were purified and Gram stained. 229(98.71 per cent) of them were Gram positive cocci and bacilli. The results show that there is a high percentage of microorganisms unable to reduce TTC in pasteurized milk, which cannot be detected by laboratory procedures based on the formation of red colonies.

Incidencia de VDRL reactivo en pacientes en puerperio inmediato en el Hospital Dr. Luis Razetti de Bercelona agosto 1994 / Incident of venereal diseases research laboratory in patients in inmediate puerperium in the Hospital Dr. \"Luis Razetti \" de Barcelona august 1994

Estudiamos 300 pacientes en puerperio inmediato (parto o cesárea) a las cuales se les realizó la prueba de VDRL cualitativa-cuantitativa. Apreciamos que el mayor porcentaje de casos reactivos se encontró en aquellas pacientes que no tuvieron contacto con consultas preventivas como el Control Prenatal y Educación Sexual. La prueba de VDRL resulto económica, sencilla y rápida como método de despistaje de nuevos casos en esa población

Novel reagents for creatine kinase

The purpose of this investigation was to develop a simple colorimetric method for creatine kinase [CK]. The new method is based on the reaction of creatine, formed enzymatically from creatine phosphate and ADP, with different glyoxal compounds. Hydrated glyoxals, such as para-nitrophenyl, 2-thiophene, 4-biphenyl, 4, 4'-biphenyl, a-naphthyl, Beta naphthyl, para-chlorophenyl, and styryl were synthesized and allowed to react with creatine. Among the glyoxals, the 2-thiophene derivative was the best in terms of the stability and intensity of the colored complex which was produced under mild alkaline conditions. The complex absorbed maximally at 460 nm with an extinction coefficient of 1.56x 10[4] M[-1] Cm[-1]. This reagent was used to determine CK in the sera of normal human beings and patients with myocardial infarction. The results obtained were in agreement with those obtained by another available method for CK. However, this new method is simple, less time consuming and employs a single reagent for color development. Such a simple method might be of value in clinical laboratories with little access to sophisticated instruments such as autoanalyzers and spectrophotometers

Evaluación de reactivos comerciales empleados en el diagnóstico de la enfermedad de Chagas en bancos de sangre de Chile: II aplicación rutinaria / Assesement of comercial kits used for Chagas' diseases diagnosis in blood banks: II routinary use

Aiming to study the applicability and reproducibility of four comercial kits used for the serological detection of Chagas disease (Chagatest-Inst Invest Paraguay, Ortho Chagas, Abbott Chagas (ELISA tests) and Estabilgen Hemo Chagas (indirect hemagglutination test), a comparative serological study was performed in 256 sera samples coming from a highly endemic area, 249 samples from a low endemic area, 180 reference sera and 2264 samples coming from three blood banks. Specificity of the kits was excellent and sensitivity ranged from 60 to 100 percent. The indirect hemagglutination test has the lower sensitivity. Some disagreements in the results were observed in the three blood banks, probably due to an unsatisfactory reactive management. We conclude that ELISA tests should be recommended for routine detection of Chagas disease and that for this purpose, a net of laboratories under the direction of a national reference center should exist. This center should assess new commercial products, train technicians and supervise the laboratories

Utilidad de dos pruebas para el diagnóstico presuntivo rápido en infección de vías urinarias y embarazo / Usefulness of two tests for the diagnosis, presuntive and quick, in urinary infection and pregnancy

Se estudiaron a 60 pacientes que acudieron al Servicio de Urgencias del INPer, refiriendo sintomatología de IVU. Se les realizó toma de urocultivo y detección de nitritos y estearasa leucocitaria en orina con la tira reactiva Multistix 10 SG (R). Se tomó como grupo testigo a 20 pacientes obstétricas de primera vez, sin sintomatología de IVU bajo la misma metodología. En el grupo de estudio se informaron 34 urocultivos negativos, 9 urocultivos contaminados y 17 urocultivos positivos, con una semsibilidad y especificidad de 94 por ciento para la prueba de nitritos y de 64 por ciento y 100 por ciento, respectivamente, para la prueba de estearasa leucocitaria. En el grupo testigo se observaron dos urocultivos contaminados, 13 negativos y 5 positivos a un microorganismo. La sensibilidad fue de 100 por ciento y la especificidad de 92 por ciento para la prueba de nitritos; y de 40 por ciento y 100 por ciento respectivamente para la estearasa leucocitaria.

Determinacao espectrofotometrica e cromatografica em fase gasosa de tricloretanol em urina / Spectrophotometric and gas chromatographic determination of trichlorethanol in urine

O tricloretanol (TCE), produto de biotransformacao dos solventes 1,1,1-tricloretano (1,1,1-TRI) e tricloretileno, e usado como indicador biologico de dose interna na vigilancia de individuos expostos ocupacionalmente a estes compostos. Neste trabalho foi realizada a otimizacao de metodo espectrofotometrico e cromatografico em fase gasosa para a determinacao do TCE, bem como se estudou a aplicacao destes metodos a analise de urina de trabalhadores expostos ao 1,1,1-TRI. A analise cromatografica com detector de captura eletronica foi efetuada em coluna SE-30 - 15//, usando-se o diclorobenzeno como padrao externo. Ambos os metodos mostraram precisao e recuperacao adequados, respectivamente de 2,2//de CV e 95,6//para o espectrofotometrico e de 2,3//de CV e 95,1//para o cromatografico. O teor medio de tricloretanol em urina, expresso em mg/g de creatinina, foi de 4,4 quando usada a espectrofotometria e de 2,4 pela cromatografia, para o grupo de individuos expostos ao 1,1,1-tricloretano. Os resultados obtidos mostraram a maior sensibilidade e especificidade da cromatografia em fase gasosa na determinacao do tricloretanol em urina

Patologia clinica en serologia y liquido cefalorraquideo de la neurosifilis

La investigacion de sifilis por medios serologicos debe realizarse pensando en tres objetivos tales como: 1) comprobar una infeccion sospechosa mediante reaccions de busqueda, el metodo aconsejado es el TPHA por su alta sensibilidad y especialidad; 2) confirmar el diagnostico aceptando los resultados reactivos como casos positivos mediante el uso del TPHA, en caso de duda reafirmarlo usando el metodo FTA/AABS, esta seguridad en el diagnostico es importante por la repercusion psico-social que significa para el paciente; 3) controlar la evolucion de la enfermedad, para ello el metodo recomendable es el VDRL cuali-cuantitativo, porque de acuerdo al titulo se califica el efecto del tratamiento. En casos de neurosifilis, los anteriores metodos son aplicables para su investigacion, pero aun la evolucion del tratamiento es dificil y es necesario desarrollar otras tecnologias como el radioinmunoensayo para detectar la proteina mielinica basica, electroforesis microzonal FTA-195 lgM por cromatografia en columna o ultracentrifugacion gradiente depresion.

Assessment of aeromonas species as a new indicator for water pollution in Alexandria

Water from Mahmoudia Canal, Mariout Lake and seawater were examined [309 samples] by the suitable scientific microbiological techniques. The results indicate the presence of Aeromonas species in different Alexandria surface water with densities more in fresh than sea water and that it has correlation with other traditional indicators especially in fresh water. It may be concluded that Aeromonas can be used as a water indicator in fresh waters but difficult to use in sea water

Efeito da turbidez do plasma na determinacao de glicose pelo metodo da ortotoluidina e glicose-oxidase / Effects of the turbidity of the blood plasma in the determination of glucose through the O-toluidine and glucose-oxydase method

Avaliou-se a interferencia da turbidez do plasma nas determinacoes de glicose em amostras biologicas com concentracoes de triglicerides entre 181 a 394 mg/dL. As dosagens de glicose foram realizadas empregando-se os metodos da ortotoluidina e o da glicose-oxidase. Procedeu-se a metodologia usual, acrescida de determinacoes de referencia ou em "branco". A analise dos resultados indica que a turbidez do plasma causada por concentracoes inferiores a 400 mg/dl de triglicerides nao interfere nas dosagens de glicose pelos dois metodos. A forte correlacao existente entre os resultados obtidos pelas duas metodologias utilizando-se ou nao as determinacoes de referencia e a fraca correlacao entre esses valores e as concentracoes de triglicerides corrobora com esta afirmacao.

Técnica CEDAT para el diagnóstico presuntivo de fibrosis quística / CEDAT atechnique for the presumptive diagnosis of cystic fibrosis

Se desarrolló una técnica para producir tiras reactivas para la determinación cualitativa de cloruos en el sudor como una prueba selectiva de diagnóstico de firbosis quística. Se realizaron dos pruebas comparativas en 23 niños, en una se les aplicó en la piel papel reactivo (CEDAT) para la determinación coalitativa de la concentración de cloruros en el sudor y, en la otra, se determinaron con aparatos especializados y de alto costo los milimoles de Cl por litros de sudro (mmol/l). Los papeles reactivos se decloraron completamente en tres,y siete presentaron dedecloraciónen la orillas y puntos en toda ls tira reactiva, algunos de los pintos eran amarrillentos. En estos casos la determinación instrumental reflejó una consentración de cloruros entre 90 y 130 mmol/L. En otras siete pruebas la decoloración de la tira reactiva fue ligera, en cuatro de éstas los papeles reactivos sólo tuvieron algunos puntos amarrillentos y en tres no cambiaron; la concentración en estos casos estuvo entre 12 y 52 mmol/L. Se eliminaron 6 casos estuvo entre 12 y 52 mmol/l. Se eliminaron 6 caos debido a que en 3 no se pudo efectuar la determinación instrumental de cloruros y en las otras tres no hubo suficiente sudor para utilizar los dos procedimientos. La Asociación Mexicana de Fibrosis Quística considera resuelto positivo un valor igual o superior a 90 mmol/l de cloruros, que es cuando el papel reactivo se decolora completamente en las orillas o con puntos blancos y amarrillos en toda su extensión. Por lo tanto, esta técnica permite hacer una selección rápida y económica de los niños que pudieran tener fibrosis quística.