AIM To evaluate the influence of creatinine methodology on the performance of chronic kidney disease(CKD)-Epidemiology Collaboration Group-calculated estimated glomerular filtration rate(CKD-EPI-eGFR) for CKD diagnosi...AIM To evaluate the influence of creatinine methodology on the performance of chronic kidney disease(CKD)-Epidemiology Collaboration Group-calculated estimated glomerular filtration rate(CKD-EPI-eGFR) for CKD diagnosis/staging in a large cohort of diabetic patients. METHODS Fasting blood samples were taken from diabetic patients attending our clinic for their regular annual examination, including laboratory measurement of serum creatinine and eGFR.RESULTS Our results indicated an overall excellent agreement in CKD staging(kappa = 0.918) between the Jaffé serum creatinine-and enzymatic serum creatinine-based CKDEPI-eGFR, with 9% of discordant cases. As compared to the enzymatic creatinine, the majority of discordances(8%) were positive, i.e., associated with the more advanced CKD stage re-classification, whereas only 1% of cases were negatively discordant if Jaffé creatinine was used for eGFR calculation. A minor proportion of the discordant cases(3.5%) were re-classified into clinically relevant CKD stage indicating mildly to moderately decreased kidney function(< 60 m L/min per 1.73 m^2). Significant acute and chronic hyperglycaemia, assessedas plasma glucose and Hb A1 c levels far above the recommended glycaemic goals, was associated with positively discordant cases. Due to a very low frequency, positive discordance is not likely to present a great burden for the health-care providers, while intensified medical care may actually be beneficial for the small number of discordant patients. On the other hand, a very low proportion of negatively discordant cases(1%) at the 60 m L/min per 1.73 m^2 eGFR level indicate a negligible possibility to miss the CKD diagnosis, which could be the most prominent clinical problem affecting patient care, considering high risk of CKD for adverse patient outcomes. CONCLUSION This study indicate that compensated Jaffé creatinine procedure, in spite of the glucose-dependent bias, is not inferior to enzymatic creatinine in CKD diagnosis/staging and therefore may provide a reliable and cost-effective tool for the renal function assessment in diabetic patients.展开更多
This study was completed by an extensive mathematical analysis. New equation to sludge filtration processes has been proposed for use in routine laboratory. The equation has been suggested to replace Ademiluyi’s cake...This study was completed by an extensive mathematical analysis. New equation to sludge filtration processes has been proposed for use in routine laboratory. The equation has been suggested to replace Ademiluyi’s cake filtration equation in view of the limitations of the latter. The new equation can be used for sludges whose compressibility factor is more than one but Ademiluyi’s cake filtration equation can only be used for sludges whose compressibility coefficient is less than one. The new sludge filtration equation was derived using tannθ reduction method. The generalized equation thus obtained resembles Ademiluyi’s equation in the mode of parameter combination except the presence of summation notation in the new equation.展开更多
Objective: To evaluate the accuracy of glomerular filtration rate formula by comparising the CKD-EPI 2009 formula and the modified Modified MDRD formula with the 99mTc-DTPA double-phase plasma method as "gold sta...Objective: To evaluate the accuracy of glomerular filtration rate formula by comparising the CKD-EPI 2009 formula and the modified Modified MDRD formula with the 99mTc-DTPA double-phase plasma method as "gold standard" respectively. Methods: Totally 166 patients diognosed as chronic kidney disease (CKD) were enrolled. The 99mTc-DTPA double-plasma method (rGFR) was used as the "gold standard". The CKD-EPI 2009 formula and the modified MDRD formula were used to calculate eGFR. Statistical software was used to analyze the correlation between the calculated values of the two formulas and the gold standard value and the bias. Then we evaluated the accuracy of the two GFR formulas. Results: Among the CKD stage 1 patients, the bias of the CKD-EPI 2009 formula was smaller than that of the Modified MDRD formula (13.9911.45;20.1815.90);both formulas were weakly correlated with the gold standard (correlation coefficients were 0.216, 0.229, P<0.01, respectively);The probability that the bias of the calculated value of the CKD-EPI 2009 formula less than 15%, 30%, and 50% of the gold standard value is smaller. Among the CKD stage 2 patients, the bias of the CKD-EPI 2009 formula was smaller than that of the Modified MDRD formula (12.748.45;15.6811.01);both formulas were moderately correlated with the gold standard (correlation coefficients were 0.568, 0.581, P<0.01, respectively);The probability that the bias of the calculated value of the CKD-EPI 2009 formula less than 15%, 30%, and 50% of the gold standard value is smaller. Among the CKD stage 3 patients, the bias of the CKD-EPI 2009 formula was smaller than that of the Modified MDRD formula (12.6410.27;12.8810.97), and both formulas were strongly correlated with the gold standard (correlation coefficients were 0.664, 0.670, P<0.01, respectively);The probability that the bias of the calculated value of the Modified MDRD formula less than 15%, 30%, and 50% of the gold standard value is smaller. Among the CKD stage 4 to 5 patients, the bias of the CKD-EPI 2009 formula was smaller than that of the Modified MDRD formula (5.585.36;5.945.20);The CKD-EPI 2009 formula and the Modified MDRD formula were strongly correlated with the gold standard (correlation coefficient r was 0.808. 0.802, P<0.01, respectively);The probability of the bias of the calculated value of the CKD-EPI 2009 formula less than 15%, 30%, and 50% of the gold standard value is smaller. In patients with decreased renal function with GFR <60 ml/min, the sensitivity and positive predictive value of the CKD-EPI 2009 formula for the diagnosis of "decreased renal function"were higher, and the specificity was comparable. Conclusion: 1. When the renal function is only slightly decreased, the accuracy of the two formulas is not good. In this condition, the CKD-EPI 2009 formula is more accurate and recommended. 2. It is necessary to further improve the current formulas especialy when it comes to value the slightly declined renal function;3. When we try to identify the stage of CKD patients, only based on eGFR may cause misclassification, it is recommended to combine the cause-GFR-albuminuria staging to assess the stage of CKD;4. The current formulas have limitations.in the case that requires a highly accurate assessment of GFR, the 99mTc-DTPA dual plasma method is recommended.展开更多
Bleaching with oxygen-containing agents and recirculation of process streams in the pulp and paper industry has increased the accumulation of oxalic acid and danger for precipitation of calcium oxalate encrusts, scali...Bleaching with oxygen-containing agents and recirculation of process streams in the pulp and paper industry has increased the accumulation of oxalic acid and danger for precipitation of calcium oxalate encrusts, scaling. Analysis and control of oxalic acid in bleaching filtrates is therefore becoming increasingly important in the pulp and paper industry. Chromatographic methods, such as IC and HPLC, are generally more time-consuming but are valuable as standard methods for determination of oxalic acid. However, the instrumentation needed is expensive and stationary. In this study, an enzymatic method based on oxalate oxidase and peroxidase was developed to determine oxalic acid in authentic bleaching filtrates using a spectrophotometer. The results showed that bleaching filtrates contain some compounds interfering with the enzymatic method. Pretreatment of the samples with activated charcoal was a successful approach for decreasing problems with interference. By using dilution followed by charcoal treatment, the results obtained from five bleaching filtrates with the colorimetric method correlated very well with those obtained using IC. This study offers a selective, fast and mobile analysis method to determine oxalic acid in bleaching fiRrates from the pulp and paper industry, The convenient enzyme-based method improves the possibilities for control of critical oxalic acid concentrations in closed-loop bleaching streams.展开更多
文摘AIM To evaluate the influence of creatinine methodology on the performance of chronic kidney disease(CKD)-Epidemiology Collaboration Group-calculated estimated glomerular filtration rate(CKD-EPI-eGFR) for CKD diagnosis/staging in a large cohort of diabetic patients. METHODS Fasting blood samples were taken from diabetic patients attending our clinic for their regular annual examination, including laboratory measurement of serum creatinine and eGFR.RESULTS Our results indicated an overall excellent agreement in CKD staging(kappa = 0.918) between the Jaffé serum creatinine-and enzymatic serum creatinine-based CKDEPI-eGFR, with 9% of discordant cases. As compared to the enzymatic creatinine, the majority of discordances(8%) were positive, i.e., associated with the more advanced CKD stage re-classification, whereas only 1% of cases were negatively discordant if Jaffé creatinine was used for eGFR calculation. A minor proportion of the discordant cases(3.5%) were re-classified into clinically relevant CKD stage indicating mildly to moderately decreased kidney function(< 60 m L/min per 1.73 m^2). Significant acute and chronic hyperglycaemia, assessedas plasma glucose and Hb A1 c levels far above the recommended glycaemic goals, was associated with positively discordant cases. Due to a very low frequency, positive discordance is not likely to present a great burden for the health-care providers, while intensified medical care may actually be beneficial for the small number of discordant patients. On the other hand, a very low proportion of negatively discordant cases(1%) at the 60 m L/min per 1.73 m^2 eGFR level indicate a negligible possibility to miss the CKD diagnosis, which could be the most prominent clinical problem affecting patient care, considering high risk of CKD for adverse patient outcomes. CONCLUSION This study indicate that compensated Jaffé creatinine procedure, in spite of the glucose-dependent bias, is not inferior to enzymatic creatinine in CKD diagnosis/staging and therefore may provide a reliable and cost-effective tool for the renal function assessment in diabetic patients.
文摘This study was completed by an extensive mathematical analysis. New equation to sludge filtration processes has been proposed for use in routine laboratory. The equation has been suggested to replace Ademiluyi’s cake filtration equation in view of the limitations of the latter. The new equation can be used for sludges whose compressibility factor is more than one but Ademiluyi’s cake filtration equation can only be used for sludges whose compressibility coefficient is less than one. The new sludge filtration equation was derived using tannθ reduction method. The generalized equation thus obtained resembles Ademiluyi’s equation in the mode of parameter combination except the presence of summation notation in the new equation.
文摘Objective: To evaluate the accuracy of glomerular filtration rate formula by comparising the CKD-EPI 2009 formula and the modified Modified MDRD formula with the 99mTc-DTPA double-phase plasma method as "gold standard" respectively. Methods: Totally 166 patients diognosed as chronic kidney disease (CKD) were enrolled. The 99mTc-DTPA double-plasma method (rGFR) was used as the "gold standard". The CKD-EPI 2009 formula and the modified MDRD formula were used to calculate eGFR. Statistical software was used to analyze the correlation between the calculated values of the two formulas and the gold standard value and the bias. Then we evaluated the accuracy of the two GFR formulas. Results: Among the CKD stage 1 patients, the bias of the CKD-EPI 2009 formula was smaller than that of the Modified MDRD formula (13.9911.45;20.1815.90);both formulas were weakly correlated with the gold standard (correlation coefficients were 0.216, 0.229, P<0.01, respectively);The probability that the bias of the calculated value of the CKD-EPI 2009 formula less than 15%, 30%, and 50% of the gold standard value is smaller. Among the CKD stage 2 patients, the bias of the CKD-EPI 2009 formula was smaller than that of the Modified MDRD formula (12.748.45;15.6811.01);both formulas were moderately correlated with the gold standard (correlation coefficients were 0.568, 0.581, P<0.01, respectively);The probability that the bias of the calculated value of the CKD-EPI 2009 formula less than 15%, 30%, and 50% of the gold standard value is smaller. Among the CKD stage 3 patients, the bias of the CKD-EPI 2009 formula was smaller than that of the Modified MDRD formula (12.6410.27;12.8810.97), and both formulas were strongly correlated with the gold standard (correlation coefficients were 0.664, 0.670, P<0.01, respectively);The probability that the bias of the calculated value of the Modified MDRD formula less than 15%, 30%, and 50% of the gold standard value is smaller. Among the CKD stage 4 to 5 patients, the bias of the CKD-EPI 2009 formula was smaller than that of the Modified MDRD formula (5.585.36;5.945.20);The CKD-EPI 2009 formula and the Modified MDRD formula were strongly correlated with the gold standard (correlation coefficient r was 0.808. 0.802, P<0.01, respectively);The probability of the bias of the calculated value of the CKD-EPI 2009 formula less than 15%, 30%, and 50% of the gold standard value is smaller. In patients with decreased renal function with GFR <60 ml/min, the sensitivity and positive predictive value of the CKD-EPI 2009 formula for the diagnosis of "decreased renal function"were higher, and the specificity was comparable. Conclusion: 1. When the renal function is only slightly decreased, the accuracy of the two formulas is not good. In this condition, the CKD-EPI 2009 formula is more accurate and recommended. 2. It is necessary to further improve the current formulas especialy when it comes to value the slightly declined renal function;3. When we try to identify the stage of CKD patients, only based on eGFR may cause misclassification, it is recommended to combine the cause-GFR-albuminuria staging to assess the stage of CKD;4. The current formulas have limitations.in the case that requires a highly accurate assessment of GFR, the 99mTc-DTPA dual plasma method is recommended.
基金This work was supported by Vinnova and the Knowledge Foundation in Sweden.
文摘Bleaching with oxygen-containing agents and recirculation of process streams in the pulp and paper industry has increased the accumulation of oxalic acid and danger for precipitation of calcium oxalate encrusts, scaling. Analysis and control of oxalic acid in bleaching filtrates is therefore becoming increasingly important in the pulp and paper industry. Chromatographic methods, such as IC and HPLC, are generally more time-consuming but are valuable as standard methods for determination of oxalic acid. However, the instrumentation needed is expensive and stationary. In this study, an enzymatic method based on oxalate oxidase and peroxidase was developed to determine oxalic acid in authentic bleaching filtrates using a spectrophotometer. The results showed that bleaching filtrates contain some compounds interfering with the enzymatic method. Pretreatment of the samples with activated charcoal was a successful approach for decreasing problems with interference. By using dilution followed by charcoal treatment, the results obtained from five bleaching filtrates with the colorimetric method correlated very well with those obtained using IC. This study offers a selective, fast and mobile analysis method to determine oxalic acid in bleaching fiRrates from the pulp and paper industry, The convenient enzyme-based method improves the possibilities for control of critical oxalic acid concentrations in closed-loop bleaching streams.
