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John C Lieske - One of the best experts on this subject based on the ideXlab platform.
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comparison of urinary albumin quantification by Immunoturbidimetry competitive immunoassay and protein cleavage liquid chromatography tandem mass spectrometry
Clinical Chemistry, 2009Co-Authors: Jesse C. Seegmiller, Timothy M. Borland, Timothy S Larson, Glen L Hortin, Denis Sviridov, John C LieskeAbstract:Background: Increased urinary albumin excretion is a well-documented diagnostic and prognostic biomarker for renal disease. Urinary albumin is typically measured in clinical settings by immunoassay methods. However, neither a reference method nor a urine albumin calibration reference material is currently available. Methods: We quantified urinary albumin in patient samples by using 3 commercially available reagent systems: DiaSorin SPQ™ and Beckman Coulter LX® 20 (immunoturbidimetric), and Siemens Immulite® (competitive immunoassay). Results were compared to values obtained by protein-cleavage liquid chromatography–tandem mass spectrometry (LC-MS/MS). Results: In general, results from the 3 immunoassays agreed with results from LC-MS/MS. However, the SPQ results showed a negative bias across all ranges of albuminuria [(0–200 mg/L, y = 0.91 x – 3.74 (CI 0.86–0.96); > 200 mg/L, y = 0.88 x – 40.30 (CI 0.76–1.00)], whereas the LX 20 showed minimal bias in the 0–200 mg/L range [ y = 0.97 x − 88 (CI 0.92–1.02)] and the Immulite assay showed positive bias in the 0–200 mg/L range [ y = 1.15 x – 4.38 (CI 1.09–1.20)]. Conclusions: These results showed a reasonable quantification of urinary albumin by representative polyclonal and monoclonal immunoassays compared to an LC-MS/MS assay. In addition, the results do not suggest the presence of nonimmunoreactive albumin in urine. However, differences in analytic performance between assays support the need for a reference calibration material and reference method to standardize clinical laboratory measurements of urinary albumin.
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comparison between Immunoturbidimetry size exclusion chromatography and lc ms to quantify urinary albumin
Clinical Chemistry, 2008Co-Authors: Aisha Shaikh, Jesse C. Seegmiller, Timothy M. Borland, Timothy S Larson, Bradley E Burns, Paula M Ladwig, Ravinder J Singh, Rajiv Kumar, John C LieskeAbstract:Background: The accurate and precise measurement of urinary albumin is critical, since even minor increases are diagnostically sensitive indicators of renal disease, cardiovascular events, and risk for death. To gain insights into potential measurement biases, we systematically compared urine albumin measurements performed by LC-MS, a clinically available immunoturbidimetric assay, and size-exclusion HPLC. Methods: We obtained unused clinical urine samples from 150 patients who were stratified by degrees of albuminuria ( 250 mg/L) as determined by the immunoturbidimetric assay used in our clinical laboratory (Roche Hitachi 912). Urine albumin was then remeasured via LC-MS and HPLC (Accumin™) assays. Results: The immunoturbidimetric assay, calibrated using manufacturer-supplied serum-derived calibrators (Diasorin), underestimated albumin compared with LC-MS. After calibration with purified HSA, this immunoturbidimetric assay correlated well with LC-MS. HPLC overestimated albumin compared with both LC-MS and Immunoturbidimetry. The current LC-MS and HPLC assays both performed poorly at concentrations <20 mg/L. Conclusions: Efforts are needed to establish gold-standard traceable calibrators for clinical assays. LC-MS is a specific method to quantify albumin in native urine when concentrations exceed 20 mg/L, and therefore could be employed for standardization among assays.
Merete Skovdal Christiansen - One of the best experts on this subject based on the ideXlab platform.
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increased urinary orosomucoid excretion predicts preeclampsia in pregnant women with pregestational type 1 diabetes
Diabetes Research and Clinical Practice, 2010Co-Authors: Merete Skovdal Christiansen, D Hesse, Pia Ekbom, U Hesse, Peter Damm, E Hommel, Bo Feldtrasmussen, Elisabeth R MathiesenAbstract:Abstract Aims We evaluated the urinary orosomucoid excretion (UOE) as a biomarker of preeclampsia and preterm delivery in pregnant women with type 1 diabetes. Methods Singleton pregnant women with pregestational type 1 diabetes were included provided one urine sample had been collected before 17 gestational weeks. Serum and urinary orosomucoid were analysed by Immunoturbidimetry. Primary outcome measurements were development of preeclampsia (blood pressure > 140/90 mmHg and proteinuria) and preterm delivery before 37 weeks. Results In total 173 women were included. The UOE increased during pregnancy. Preeclampsia developed in 20 women and 65 women delivered preterm. Using logistic regression analysis we found that UOE > 1.37 mg/l (OR: 6.85 (95% CI: 1.97–23.88; p p 120 mmHg (4.12 (1.35–12.59); p 20 years (3.69 (1.18–11.52); p 7%. The remaining covariates included in the regression models were BMI, serum creatinine, smoking and microalbuminuria. Conclusions Increased UOE early in pregnancy predicted preeclampsia in women with pregestational type 1 diabetes independently of albuminuria and other known risk factors. No association to preterm delivery was found.
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monitoring urinary orosomucoid in acute inflammation observations on urinary excretion of orosomucoid albumin α1 microglobulin and igg
Clinical Chemistry, 2005Co-Authors: Erik Magid, Henrik Guldager, Dan Hesse, Merete Skovdal ChristiansenAbstract:Background: Inflammation-associated proteinuria in acute, nonrenal disease is a common but poorly understood phenomenon. We performed an observational study of the urinary excretion of orosomucoid (α1-acid glycoprotein), albumin, α1-microglobulin (protein HC), and IgG to obtain quantitative and temporal data on these 4 proteins. Methods: Urine samples were collected at daily intervals for up to 23 days from 6 patients with surgery-induced inflammation and at hourly intervals for a 24-h period from 7 sepsis patients. Urinary protein concentrations were assessed by Immunoturbidimetry. Results: During surgery-induced inflammation, the increase and decrease in orosomucoid excretion mirrored changes in plasma C-reactive protein. Values for all 4 urinary proteins were increased in sepsis patients. The observed maximum increases in urinary protein excretion relative to the upper reference values were 280-fold for orosomucoid, 98-fold for α1-microglobulin, 33-fold for albumin, and 26-fold for IgG. Conclusions: Orosomucoid, usually present in plasma and urine in much lower concentrations than albumin, is increased in urine to concentrations equal to or higher than albumin in proteinuria associated with acute inflammation. The pathophysiologic mechanisms responsible for this markedly increased excretion are unknown. Monitoring of urinary excretion of orosomucoid and other specific proteins, expressed as protein/creatinine ratios, may provide a window for clinically relevant real-time observation of changes in acute inflammatory processes. Orosomucoid in urine may be a more informative marker than albumin for inflammation.
Farah Naz - One of the best experts on this subject based on the ideXlab platform.
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method comparison of particle enhanced Immunoturbidimetry peit with high performance liquid chromatography hplc for glycated hemoglobin hba1c analysis
Clinical Diabetes and Endocrinology, 2021Co-Authors: Shabnam Dildar, Sheharbano Imran, Farah NazAbstract:High Performance Liquid Chromatography (HPLC) technique is considered as a gold standard for HbA1c analysis however all laboratories cannot adopt it due to certain limitations. Our aim was to compare Particle Enhanced Immunoturbidimetry (PEIT) method with High Performance Liquid Chromatography (HPLC) for HbA1c analysis. All blood samples were analyzed by HPLC assay on a Bio-Rad D-10 analyzer and PEIT on an Erba XL-200 analyzer. Precision studies were undertaken and Coefficient of Variation (%CV) calculated. Systemic Error (SE), Random Error (RE) and Total Error (TEcalc) were obtained. The Total Allowable Error (TEa) set by the National Glycohemoglobin Standardization Program (NGSP) for HbA1c is 6%.The acceptable evaluation method is where TEcalc is less than TEa. The Precision studies were satisfactory with Coefficient of Variation (%CV) being less than 4% for both techniques. Mean HbA1c levels were slightly higher from HPLC than PEIT 9.07 ± 2.23% and 8.93 ± 2.10% respectively, although the difference was minimal. RE was 1.41%, TEcalc was 1.55%, which was less than TEa set by the NGSP. Both methods strongly correlated with the correlation coefficient (r) 0.9716, p < 0.0001. Our study showed HbA1c analysis by PEIT technique is precise, accurate, rapid and convenient and can be employed as an alternative to HPLC technique in countries where cost is a major problem for diagnosis and treatment.
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Method comparison of Particle Enhanced Immunoturbidimetry (PEIT) with High Performance Liquid Chromatography (HPLC) for glycated hemoglobin (HbA1c) analysis
'Springer Science and Business Media LLC', 2021Co-Authors: Shabnam Dildar, Sheharbano Imran, Farah NazAbstract:Abstract Background and objective High Performance Liquid Chromatography (HPLC) technique is considered as a gold standard for HbA1c analysis however all laboratories cannot adopt it due to certain limitations. Our aim was to compare Particle Enhanced Immunoturbidimetry (PEIT) method with High Performance Liquid Chromatography (HPLC) for HbA1c analysis. Method All blood samples were analyzed by HPLC assay on a Bio-Rad D-10 analyzer and PEIT on an Erba XL-200 analyzer. Precision studies were undertaken and Coefficient of Variation (%CV) calculated. Systemic Error (SE), Random Error (RE) and Total Error (TEcalc) were obtained. The Total Allowable Error (TEa) set by the National Glycohemoglobin Standardization Program (NGSP) for HbA1c is 6%.The acceptable evaluation method is where TEcalc is less than TEa. Results The Precision studies were satisfactory with Coefficient of Variation (%CV) being less than 4% for both techniques. Mean HbA1c levels were slightly higher from HPLC than PEIT 9.07 ± 2.23% and 8.93 ± 2.10% respectively, although the difference was minimal. RE was 1.41%, TEcalc was 1.55%, which was less than TEa set by the NGSP. Both methods strongly correlated with the correlation coefficient (r) 0.9716, p
Jesse C. Seegmiller - One of the best experts on this subject based on the ideXlab platform.
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comparison of urinary albumin quantification by Immunoturbidimetry competitive immunoassay and protein cleavage liquid chromatography tandem mass spectrometry
Clinical Chemistry, 2009Co-Authors: Jesse C. Seegmiller, Timothy M. Borland, Timothy S Larson, Glen L Hortin, Denis Sviridov, John C LieskeAbstract:Background: Increased urinary albumin excretion is a well-documented diagnostic and prognostic biomarker for renal disease. Urinary albumin is typically measured in clinical settings by immunoassay methods. However, neither a reference method nor a urine albumin calibration reference material is currently available. Methods: We quantified urinary albumin in patient samples by using 3 commercially available reagent systems: DiaSorin SPQ™ and Beckman Coulter LX® 20 (immunoturbidimetric), and Siemens Immulite® (competitive immunoassay). Results were compared to values obtained by protein-cleavage liquid chromatography–tandem mass spectrometry (LC-MS/MS). Results: In general, results from the 3 immunoassays agreed with results from LC-MS/MS. However, the SPQ results showed a negative bias across all ranges of albuminuria [(0–200 mg/L, y = 0.91 x – 3.74 (CI 0.86–0.96); > 200 mg/L, y = 0.88 x – 40.30 (CI 0.76–1.00)], whereas the LX 20 showed minimal bias in the 0–200 mg/L range [ y = 0.97 x − 88 (CI 0.92–1.02)] and the Immulite assay showed positive bias in the 0–200 mg/L range [ y = 1.15 x – 4.38 (CI 1.09–1.20)]. Conclusions: These results showed a reasonable quantification of urinary albumin by representative polyclonal and monoclonal immunoassays compared to an LC-MS/MS assay. In addition, the results do not suggest the presence of nonimmunoreactive albumin in urine. However, differences in analytic performance between assays support the need for a reference calibration material and reference method to standardize clinical laboratory measurements of urinary albumin.
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comparison between Immunoturbidimetry size exclusion chromatography and lc ms to quantify urinary albumin
Clinical Chemistry, 2008Co-Authors: Aisha Shaikh, Jesse C. Seegmiller, Timothy M. Borland, Timothy S Larson, Bradley E Burns, Paula M Ladwig, Ravinder J Singh, Rajiv Kumar, John C LieskeAbstract:Background: The accurate and precise measurement of urinary albumin is critical, since even minor increases are diagnostically sensitive indicators of renal disease, cardiovascular events, and risk for death. To gain insights into potential measurement biases, we systematically compared urine albumin measurements performed by LC-MS, a clinically available immunoturbidimetric assay, and size-exclusion HPLC. Methods: We obtained unused clinical urine samples from 150 patients who were stratified by degrees of albuminuria ( 250 mg/L) as determined by the immunoturbidimetric assay used in our clinical laboratory (Roche Hitachi 912). Urine albumin was then remeasured via LC-MS and HPLC (Accumin™) assays. Results: The immunoturbidimetric assay, calibrated using manufacturer-supplied serum-derived calibrators (Diasorin), underestimated albumin compared with LC-MS. After calibration with purified HSA, this immunoturbidimetric assay correlated well with LC-MS. HPLC overestimated albumin compared with both LC-MS and Immunoturbidimetry. The current LC-MS and HPLC assays both performed poorly at concentrations <20 mg/L. Conclusions: Efforts are needed to establish gold-standard traceable calibrators for clinical assays. LC-MS is a specific method to quantify albumin in native urine when concentrations exceed 20 mg/L, and therefore could be employed for standardization among assays.
Jing Cheng - One of the best experts on this subject based on the ideXlab platform.
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increased urinary excretion of orosomucoid is a risk predictor of diabetic nephropathy
Nephrology, 2009Co-Authors: Hongjuan Jiang, Guangju Guan, Rui Zhang, Jing ChengAbstract:SUMMARY Aim: Identification of the risk predictor of diabetic nephropathy (DN) remains a major challenge currently. Thus, proteomic approaches to identify DN-related biomarker were performed. Methods: A comparative proteomic approach of 2-D gel electrophoresis (2-DE) and mass spectrometry to identify biomarkers in urine samples from 12 DN patients (six type 1 and six type 2 diabetic patients) and six healthy controls. Then, the urinary level of identified protein biomarker was detected by Immunoturbidimetry assay in urine samples from 90 type 1 and type 2 diabetic patients with normo-, micro- and macroalbuminuria (n = 30 in each group), and 30 healthy controls. Results: A novel DN-related protein, orosomucoid (α1-acid glycoprotein), was identified by proteomic method. Its abundance was highly upregulated (>eightfold) in DN patients. The data of Immunoturbidimetry assay showed urinary orosomucoid excretion rate (UOER) was gradually increased in the normo-, micro- and macroalbuminuria group versus control (0.71 ± 0.41, 1.93 ± 0.68, 2.88 ± 0.94 vs 0.39 ± 0.28 ug/min, P < 0.05). The result indicated that UOER increased in early stage of DN and gradually increased with the development of DN. Also, Pearson's correlation analysis indicated UOER was positively correlated with urinary albumin excretion rate, serum creatinine and C-reactive protein (r = 0.830, 0.787 and 0.360, respectively; P < 0.05). Multivariate logistic regression analysis also showed that increased UOER was an independent risk factor for DN (odds ratio = 3.10, P < 0.0001). Conclusion: Urinary orosomucoid is a DN-related biomarker, which is associated with the development and progression of DN. Furthermore, increased UOER is an independent risk factor of DN.