RESUMO
BACKGROUND: The BacterioScan 216Dx laser microbial growth monitoring system was evaluated as an option for preurine culture screening of preserved urine specimens at an acute care medical center. METHODS: The BacterioScan 216Dx system performance characteristics and the economic impact (cost effectiveness) for the laboratory were assessed. Urinalysis performance compared to urine culture was assessed if urinalysis was ordered as part of the patient care set. RESULTS: When compared to urine culture, the BacterioScan had an overall performance with corresponding 95% confidence intervals of 76% (68-83) sensitivity, 84% (80-87) specificity, 55% (48-63) positive predictive value, and 93% (90-95) negative predictive value for 610 randomly selected preserved urine specimens. Urinalysis compared to urine culture overall performance was 59% (48-69) sensitivity, 87% (83-90) specificity, 53% (43-63) positive predictive value, 89% (86-92) negative predictive value for 414 urine specimens. CONCLUSIONS: While the system did improve the turnaround time to a negative report, adoption of the BacterioScan system would increase the reagent budget for laboratory urine culture by 2.34 times the current cost, potentially making BacterioScan prohibitive in a budget restricted environment. Additionally, performance when compared to traditional urine culture was less than acceptable for a diagnostic laboratory to use as a stand-alone urinary tract infection screen.
Assuntos
Técnicas Bacteriológicas , Urinálise , Técnicas Bacteriológicas/economia , Técnicas Bacteriológicas/métodos , Técnicas Bacteriológicas/estatística & dados numéricos , Humanos , Sensibilidade e Especificidade , Urinálise/economia , Urinálise/métodos , Urinálise/estatística & dados numéricos , Infecções Urinárias/diagnóstico , Infecções Urinárias/microbiologiaRESUMO
A rapid and simple extraction technique based on aqueous two-phase system (ATPS) was developed for separation and enrichment of vitamin B(12) in urine samples. The proposed ATPS-based method involves the application of the hydrophilic ionic liquid (IL) 1-hexyl-3-methylimidazolium chloride and K(2)HPO(4). After the extraction procedure, the vitamin B(12)-enriched IL upper phase was directly injected into the high performance liquid chromatography (HPLC) system for analysis. All variables influencing the IL-based ATPS approach (e.g., the composition of ATPS, pH and temperature values) were evaluated. The average extraction efficiency was 97% under optimum conditions. Only 5.0 mL of sample and a single hydrolysis/deproteinization/extraction step were required, followed by direct injection of the IL-rich upper phase into HPLC system for vitamin B(12) determination. A detection limit of 0.09 µg mL(-1), a relative standard deviation (RSD) of 4.50% (n=10) and a linear range of 0.40-8.00 µg mL(-1) were obtained. The proposed green analytical procedure was satisfactorily applied to the analysis of samples with highly complex matrices, such as urine. Finally, the IL-ATPS technique could be considered as an efficient tool for the water-soluble vitamin B(12) extraction.
Assuntos
Métodos Analíticos de Preparação de Amostras/métodos , Fracionamento Químico/métodos , Líquidos Iônicos/química , Urinálise/métodos , Vitamina B 12/isolamento & purificação , Vitamina B 12/urina , Água/química , Métodos Analíticos de Preparação de Amostras/economia , Cromatografia Líquida de Alta Pressão , Humanos , Fatores de Tempo , Urinálise/economiaRESUMO
BACKGROUND: The first step in the diagnosis of diabetic nephropathy is to measure albumin in a spot urine sample. The aim of this study was to assess the accuracy of urinary albumin concentration (UAC), urinary albumin-to-creatinine ratio (UACR), and the Micral-Test II in a random urine specimen (RUS) for microalbuminuria screening in diabetes mellitus. METHODS: Two hundred and seventy-eight patients collected 24 h timed urine specimens followed by RUS. Albumin (immunoturbidimetry) and creatinine were measured in protein-negative (Combur-Test) urine samples. Samples were classified as normoalbuminuric [24 h urinary albumin excretion rate (UAER) <20 microg/min; n = 189] and microalbuminuric (UAER =20-199 microg/min; n = 89). Micral-Test II readings were performed in 130 RUS. Receiver operating characteristics (ROC) curves were constructed using UAER as the reference standard. RESULTS: The areas under the ROC curves were similar for UAC (0.934+/-0.032) and UACR (0.920+/-0.035; P = 0.626), but the Micral-Test II had lower accuracy to diagnose microalbuminuria (area = 0.846+/-0.047) than UAC (P = 0.014). The first cutoff point with 100% sensitivity for UAC was 14.4 mg/l (specificity =77.2%), and 15.7 mg/g for UACR (specificity =73.0%). Concerning the Micral-Test II, sensitivity and specificity for the 20 mg/l cutoff point were 90.0 and 46.0%, respectively. The agreement between UAER and the Micral-Test II for microalbuminuria diagnosis was 55.8% (kappa = 0.22; P < 0.001). The cost of diagnosing microalbuminuria was 1.74 dollars(UAC), 2.00 dollars (UACR) and 4.09 dollars (Micral-Test II) per patient. CONCLUSIONS: Measurement of UAC in a RUS was the best choice for the diagnosis screening of microalbuminuria in diabetic patients, considering cost and accuracy.
Assuntos
Albuminúria/diagnóstico , Creatinina/urina , Diabetes Mellitus Tipo 1/urina , Diabetes Mellitus Tipo 2/urina , Programas de Rastreamento/métodos , Urinálise/métodos , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Albuminúria/etiologia , Albuminúria/urina , Análise Custo-Benefício , Diabetes Mellitus Tipo 1/complicações , Diabetes Mellitus Tipo 2/complicações , Feminino , Humanos , Masculino , Programas de Rastreamento/economia , Pessoa de Meia-Idade , Nefelometria e Turbidimetria , Curva ROC , Reprodutibilidade dos Testes , Urinálise/economiaRESUMO
O valor da sedimentoscopia em amostras de urina com exame físico-químico normal é questionado na literatura médica estrangeira, sendo que muitos pesquisadores a julgam desnecessária. Procurando contribuir para a elucidação desta dúvida e levando-se em conta que a maioria dos laboratórios brasileiros sempre executa o exame completo, foi analisada uma amostragem de uma clientela essencialmente ambulatorial, cujas requisições não permitiam determinar se havia finalidade diagnóstica. Fez-se um estudo de 10.234 amostras, que foram submetidas ao exame de rotina, sendo que 5.000 apresentaram exames físico-químicos normais. Destas foi feita uma avaliação dos achados da microscopia do sedimento que pudessem ser considerados possivelmente relevantes clinicamente. Entre esses achados, os de maior incidência foram: cilindros (29 exames - 0,58 por cento) e piócitos em número igual ou superior a cinco por campo (26 exames - 0,52 por cento). Todos os demais parâmetros foram encontrados em números iguais ou inferiores a 0,4 por cento. Um percentual de 98,02 por cento destas amostras não revelou anormalidade à microscopia. A análise estatística pelo método do X² (p < 0,01) sugere que não há necessidade da execução da sedimentoscopia nas urinas sem anormalidades no exame físico-químico, o que representaria uma redução de 48,85 por cento dos sedimentos examinados. Desta forma se obteria uma sensível economia de tempo e de gastos, sem nenhum prejuízo para o paciente
Assuntos
Humanos , Fitas Reagentes , Bacteriúria , Valor Preditivo dos Testes , Microscopia , Custos e Análise de Custo , Urinálise/economia , Urinálise/instrumentaçãoRESUMO
The diagnosis of megaloblastic anaemias caused by cobalamine or folate deficiency are still difficult. The dosage of these two substances help to differenciate between both carencies, but it is not determinant of any of them and is an expensive method. Homocisteinuria (HC), methylmalonuria (MMA) and formiminoglutamic acid (FIGLU) are cheap tests which could help in the differential diagnosis, if they are used properly. We report 62 patients to whom we made these test simultaneously. All of the patients received 10 micrograms of vit B12 and after 72 hours, 1 mg/day of folic acid (for 3 days). In both cases waiting for the increase of reticulocytyes up to 150 x 10(9)/L as a form of therapeutic test of diagnosis. By this simple way we have detected 97.9% of specificity for cobalamin deficiency of the MMA test, and only 4.2% for HC. This last test had increased its specificity up to 91.6% in association with the negative FIGLU test. We have also found a high specificity (92.3%) for FIGLU due to the detection of folate deficiency, in opposition with other authors who had described it as low as 50%. We have also compared the costs of the 3 tests with the dosage of cobalamine and folate, and we have found that the formers are 11 times less expensive than the last ones.