Summary
The detection of microalbuminuria has a high prognostic value in diabetic patients
with no symptoms of clinical nephropathy. Attention has been focused on the development
of a simple, reproducible, specific, and, above all, sensitive method to detect albuminuria
in the urine. The method is based on the competitive binding between albumin in the
urine to be tested and a fixed amount of radiolabelled albumin to anti-albumin immunoglobulins
in solid phase. The immunoglobulin C fraction of a rabbit anti-human albumin antiserum
was left to coat highly adsorbent polystyrene microtitre tubes. While the aspecific
tube binding was overcome by saturation with a solution of gelatine, increasing dilutions
of standard albumin or the diluted urine samples to be tested were left to incubate
with an equal volume of radiolabelled albumin at room temperature for 1 hour. The
cold/hot albumin mixture was added to anti-albumin immunoglobulin-coated tubes, which
had been repeatedly washed, and left to incubate. After washing, radioactivity was
assessed. This assay has proved to be fast, simple and highly sensitive since it detects
up to 25 ng of albumin per ml and is of value in large-scale screening for microalbuminuria
in diabetic patients.
Key-Words
Microalbuminuria
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Diabetes
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Nephropathy
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Routine Method
