NGAL can be reliably measured in clinical urine samples, although pyuria is an important potential confounder. In our cohort, increased urinary NGAL was associated with AKI by the AKIN criteria; however, the sensitivity and specificity were only fair, in part because patients with pre-renal causes are not excluded by AKIN criteria. Conversely, findings on microscopic urinalysis are very specific for AKI.

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 (<20 mg/L, 20–250 mg/L, >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.

The results suggest that in patients with MN, quantification of low-, medium- and high-molecular-weight urinary proteins may be associated with rate of response to RTX, but do not correlate with longer term outcomes.

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.

In youth with type 1 diabetes, prolonged moderate aerobic exercise results in a consistent reduction in plasma glucose and the frequent occurrence of hypoglycemia when preexercise glucose concentrations are <120 mg/dl. Moreover, treatment with 15 g of oral glucose is often insufficient to reliably treat hypoglycemia during exercise in these youngsters.