Biological variability of albumin excretion rate and albumin-to-cretinine ratio in hypertensive type 2 diabetic patients

Andrea Mosca, Renata Paleari, Ferruccio Ceriotti, Annunziata Lapolla, Domenico Fedele, Marco Comaschi, Loris Confortin, Carlo Coscelli, Gaetano Crepaldi, Domenico Cucinotta, Giacomo De Ferrari, Pietro Paolo Faronato, Paolo Fumelli, Aldo Galuzzo, Giovanni Ghirlanda, Mario Iorini, Mario Maioli, Valerio Miselli, Stefano Del Prato, Guido PozzaFausto Santeusanio, Antonio Tiengo, Mariella Trovati, Claudio Velussi

Research output: Contribution to journalArticlepeer-review

Abstract

The importance of measuring microalbuminuria is well established. However, only scanty data are available concerning the biological variability of albumin excretion in type 2 diabetic subjects. We report our experience from a large clinical trial of a new antihypertensive drug (Lercanidipine) designed to reduce albumin excretion and blood pressure in type 2 diabetic patients with hypertension and microalbuminuria. Eighty seven patients with persistent microalbuminuria were studied within 1 year of the clinical trial. The measurements were performed on blood and timed urine samples frozen at -80°C and shipped to a central laboratory unit. Preliminary experiments were performed to assess albumin stability in urine under various conditions (4°C -20°C and -80°C), particularly with regard to the albumin/creatinine ratio. Urine samples can be stored up to 3 weeks at 4°C or up to 2 months at -80°C. The biological variability of the albumin excretion rate was 25.7%, while that of the albumin/creatinine ratio was 13.4%. These data are useful in defining the analytical goals of imprecision for microalbuminuria (CV = 13% for albumin, and CV = 6% for albumin/creatinine ratio). No correlation between albumin/creatinine ratio and HbA1c was found in the cohort of 61 microalbuminuric patients who completed the trial. The results of this study confirm that the albumin/creatinine ratio is much more suitable for monitoring albumin excretion in longitudinal studies than the albumin excretion rate.

Original languageEnglish
Pages (from-to)1229-1233
Number of pages5
JournalClinical Chemistry and Laboratory Medicine
Volume41
Issue number9
DOIs
Publication statusPublished - 2003

Keywords

  • Albuminuria
  • Biological variability
  • Diabetes mellitus
  • Diabetic nephropathy
  • Glycated hemoglobin
  • Specimen handling

ASJC Scopus subject areas

  • Clinical Biochemistry

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