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 language | English |
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Pages (from-to) | 1229-1233 |
Number of pages | 5 |
Journal | Clinical Chemistry and Laboratory Medicine |
Volume | 41 |
Issue number | 9 |
DOIs | |
Publication status | Published - 2003 |
Keywords
- Albuminuria
- Biological variability
- Diabetes mellitus
- Diabetic nephropathy
- Glycated hemoglobin
- Specimen handling
ASJC Scopus subject areas
- Clinical Biochemistry