Ki-67 Protein Concentrations in Urothelial Bladder Car- Cinomas Are Related to Ki-67-specific Rna Concentra- Tions

creatine in plasma. For GAA in plasma, the less satisfying results are probably attributable to a lack of sensitivity of our tandem spectrometer. To assess the ability to detect CDS patients, we analyzed a urine sample from a 21-year-old patient with GAMT deficiency and compared the results with the values for controls. Reference values were estimated by use of control urines (n 47; age range, 5–23 years of age) with nonparametric analysis (5th and 95th percentiles). As expected, urinary GAA was increased (386 mmol/mol creatinine; values for control group, 7–88 mmol/mol creatinine), and urinary creatine was in the range of values obtained for the controls (34 mmol/mol creatinine; values for control group, 12–585 mmol/mol creatinine). In summary, we have described and validated a LC/ MS/MS method for the diagnosis of CDS-affected patients that quantifies GAA and creatine in urine and plasma by use of stable-isotope-labeled creatine and GAA as internal standards. This analytical method shows advantages of speed, specificity, linearity over large concentration ranges, and comparability with a stable-isotopedilution GC/MS method.