Objective To determine the diagnostic value of fractional exhaled nitric ( FeNO)measurement in diagnosis of bronchial asthma. Methods The patients with unkown-cause respiratory symptoms including wheezing, cough, and breathlessness were enrolled from August to September in 2008.FeNO was measured by nitric oxide analyzer ( NIOX; Aerocrine AB; Solna, Sweden) . Bronchial challenge test ( BCT) or bronchodilator test was defined as golden standard for asthma diagnosis. The value of FeNO was assessed and the optimal operating point of FeNO testing was determined by the means of the receiver operating characteristic ( ROC) curves. Results A total of 101 patients were enrolled, in which 48 cases were diagnosed as asthma by positive yield in BCT ( in 38 cases) or bronchodilator test ( in 10 cases) . The severity of airway hyperresponsiveness ( AHR) judged by BCT was mild in 15 cases, moderate in 15 cases and severe in 8 cases. The levels of FeNO of asthma group were higher than those of non-asthma group [ ( 68. 19 ±43. 00) ppb vs ( 19. 52 ±10. 60) ppb, P lt; 0. 05] . A linear correlation of FeNO with lnPD20 FEV1 was revealed in the cases with AHR. Area under ROC curve was 0. 9. The optimal diagnostic cutoff point was 36. 5 ppb which was capable of differentiating asthma and non-asthma with sensitivity of 92. 7% ,specificity of 83. 3% , positive predictive value of 79. 17% , negative predictive value of 94. 34% and accuracy of 87. 13% . Conclusion FeNO test may be helpful in the diagnosis of asthma with high sensitivity and specificity.
Objective To evaluate the diagnostic value of creatinine, as an indicator of glomerular filtration function injury. Methods MEDLINE, EMBASE and CBM-disc were searched from 1993 to 2003. Thirty four articles that described biomedical markers to indicate glomerular filtration function injury were selected according to specified inclusion criteria. These articles were evaluated systematically using SPSS, EXCEL, and RevMan software. Results The odds ratios of creatinine was 24.23. Areas under summarized receiver operator characteristic curve were 0.871. Selected articles were divided to groups for analysis according to diagnostic standards, such as inulin, iohexol, 125I-iothalamate, 51Cr-EDTA, 99mTc-DTPA and sodium thiosulfate. Inter-group analysis of creatinine was not statistically different (P=0.32). Intra-group analysis of inulin, 51Cr-EDTA, 99mTc-DTPA, and iohexol was not statistically different, P value were 0.61, 0.50, 0.36, 0.32, respectively. Intra-group analysis of 125I-iothalamate was statistically different (P=0.02). Selected articles were sub-grouped according to different analytic techniques of creatinine. Intra-group analysis by the Jaffe method was statistically different (P=0.03), intra-group analysis of enzymatic method was not statistically different (P=0.22). Conclusion The diagnostic value of creatinine was not qualified enough to indicate glomerular filtration function injury. Enzymatic methods are recommended to measure creatinine. Inulin or 51Cr-EDTA is suggusted to measure glomerular filtration rate in investigation of creatinine，and feedforward cohort is recommended to apply.