RESUMO
OBJECTIVE: Recent studies of urine-based enzyme-linked immunosorbent assays (ELISA) for detection of antibody to Helicobacter pylori (H. pylori) have already shown high sensitivity and specificity in adults. The diagnostic accuracy of these assays in children was investigated. METHODS: The results of serum and urine-based ELISAs were compared with those of 13C-urea breath tests (13C-UBT) and/or detection of faecal H. pylori antigen in 68 children. The effect of urine total immunoglobulin G (IgG) levels on the ELISA results for anti-H. pylori antibodies in urine was also examined. RESULTS: The sensitivity, specificity and accuracy of the serum ELISA were 72.7%, 96.3%, and 92.3% respectively, while those of the urine-based ELISA were 92.3%, 76.4%, and 79.4% respectively. The level of urine total IgG in children with false-positive results in the urine-based ELISA, was significantly higher than that in children who showed negative results in both the urine-based ELISA and the 13C-UBT and/or faecal H. pylori antigen tests. Human gamma-globulin affected the urine-based ELISA results at final concentrations of 2.0 mg/dL, 3.0 mg/dL, and 4.0 mg/dL; the anti-H. pylori antibody values were significantly higher than the ELISA values without the addition of human gamma-globulin. CONCLUSION: The findings suggested that the specificity of urine-based ELISA for detection of H. pylori antibodies is low in children, since high urinary levels of total IgG increase the likelihood of false-positive results.
Assuntos
Ensaio de Imunoadsorção Enzimática/métodos , Infecções por Helicobacter/urina , Helicobacter pylori/isolamento & purificação , Adolescente , Fatores Etários , Criança , Pré-Escolar , Feminino , Humanos , Imunoglobulina G/urina , Lactente , Modelos Lineares , Masculino , Sensibilidade e EspecificidadeRESUMO
Method-performance studies were conducted for the notified revised analytical method of inabenfide in unpolished rice. Six laboratories analyzed unpolished rice spiked with 0.05 microgram/g of inabenfide in replicate. Mean recovery from rice was 85.0%. Repeatability relative standard deviation value was 4.2% and reproducibility relative standard deviation value was 8.1%. The detection limits were 0.002-0.01 microgram/g.
Assuntos
Ácidos Isonicotínicos/análise , Oryza/química , Reguladores de Crescimento de Plantas/análise , Reprodutibilidade dos TestesRESUMO
Method-performance studies were conducted for the notified revised analytical method of chinomethionat in agricultural products by interlaboratory study. Six laboratories analyzed unpolished rice, cabbage, squash, lettuce and orange spiked with 0.1 microgram/g of chinomethionat in replicate. Mean values of recovery from the 5 crops ranged from 90.2 to 100.5%. Repeatability relative standard deviations ranged from 4.4 to 7.7% and reproducibility relative standard deviations ranged from 10.9 to 17.1%. The detection limits were 0.003-0.012 microgram/g.
