An improved radial-immunodiffusion technique for measuring albumin in unconcentrated urine.
By exploiting the polymer-enhancing effect on the immunological precipitation, we have developed a highly sensitive, single radial-immunodiffusion (SRID) method for measuring albumin in urine. As little as 20 ng of albumin could be measured in a 4-microL sample of urine. Both within- and between-plate coefficients of variation were less than 5% over the range of albumin concentrations between 5 and 80 mg/L. Accuracy, as estimated from recovery studies, was also very good. The method is simple to perform and inexpensive (it requires only very small amounts of antiserum). The urinary albumin output, as determined on timed urine collections from 117 healthy persons (66 women and 51 men), ranged from 1.8 to 17.7 micrograms/min, with a geometric mean value of 6.8 micrograms/min (log SD = 0.1894). Based on the above-mentioned advantages of the method, we recommend it for routine use in clinical laboratories.
D000419:Albuminuria / Q000175:diagnosis*; D006801:Humans; D005779:Immunodiffusion