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Detecting microalbuminuria by urinary albumin/creatinine concentration ratio
J S Jensen1, P Clausen, K Borch-Johnsen
1Department of Medicine P., Rigshospitalet, University of Copenhagen, Denmark.
Background:
Microalbuminuria, i.e. a subclinical increase of the albumin excretion rate in urine, may be a novel atherosclerotic risk factor. This study aimed to test whether microalbuminuria can be identified by measurement of urinary albumin concentration or urinary albumin/creatinine concentration ratio, instead of the usual measurement of the albumin excretion rate in a timed urine collection.
Methods:
All 2579 subjects analysed were screened in a population based epidemiological study. Participants with diabetes mellitus, renal disease, haematuria, or urinary tract infection were not included. Urinary albumin (Ualb) and creatinine (Ucreat) concentrations were measured in an overnight collected sample by enzyme-linked immunosorbent and colorimetric assays, respectively. Urinary albumin excretion rate (UAER) and urinary albumin/creatinine concentration ratio (Ualb/Ucreat) were calculated.
Results:
The correlation between Ualb and UAER was 0.72 (n = 2579, P < 0.001), and the correlation between Ualb/Ucreat and UAER was 0.81 (n = 2579, P < 0.001). In the detection of microalbuminuria, the nosographic sensitivity and specificity, and the diagnostic specificity were 58%, 97%, and 66% for Ualb, and 73%, 97%, and 73% for Ualb/Ucreat, respectively.
Conclusions:
It is concluded that measurement of the albumin/creatinine concentration ratio is a specific and quite sensitive alternative to measurement of the urinary albumin excretion rate in timed collections, when screening for microalbuminuria.
Insights
Screening for microalbuminuria can be effectively done using the albumin/creatinine ratio in urine. This method is a specific and sensitive alternative to timed urine collections for detecting this early sign of kidney damage.
Area of Science:
- Nephrology
- Cardiovascular Medicine
- Clinical Chemistry
Background:
- Microalbuminuria, a subclinical increase in urinary albumin excretion, is a potential novel atherosclerotic risk factor.
- Early detection of microalbuminuria is crucial for managing cardiovascular and renal health.
- Traditional methods for measuring albumin excretion rate (UAER) require timed urine collections, which can be cumbersome.
Purpose of the Study:
- To evaluate the utility of urinary albumin concentration (Ualb) and urinary albumin/creatinine concentration ratio (Ualb/Ucreat) for identifying microalbuminuria.
- To compare these simpler methods with the standard UAER measurement.
- To determine if Ualb or Ualb/Ucreat can replace timed urine collections for microalbuminuria screening.
Main Methods:
- A population-based epidemiological study screened 2579 subjects.
- Exclusion criteria included diabetes mellitus, renal disease, haematuria, or urinary tract infection.
- Urinary albumin and creatinine concentrations were measured in overnight samples; UAER and Ualb/Ucreat were calculated.
Main Results:
- A strong correlation was observed between Ualb and UAER (r=0.72, P<0.001) and between Ualb/Ucreat and UAER (r=0.81, P<0.001).
- For microalbuminuria detection, Ualb/Ucreat demonstrated higher sensitivity (73%) and diagnostic specificity (73%) compared to Ualb (58% sensitivity, 66% diagnostic specificity).
- Both methods showed high specificity (97%) in identifying microalbuminuria.
Conclusions:
- Measurement of the albumin/creatinine concentration ratio is a specific and sensitive alternative for screening microalbuminuria.
- This method offers a practical advantage over the traditional urinary albumin excretion rate measurement in timed collections.
- Ualb/Ucreat provides a reliable and simpler approach for identifying individuals at risk.