Significance of urinary albumin index in the urine collected arbitrarily in the morning.

To evaluate urinary albumin index (UAI), the relationship between albumin excretion rate (AER) in the urine stored for 24 h and UAI in the urine collected arbitrarily on the morning of the same day was studied in 123 inpatients. The patients were admitted to our hospital from September 1, 1988 to August 31, 1989, consisting of 67 non-insulin dependent diabetics (Group 1), 40 patients with collagen disease (Group 2), and 16 patients with primary renal disease (Group 3). The relationship between log(e) AER and log(e)UAI was plotted on a graph. Pearson's rank correlation coefficients of Groups 1-3, Group 1, Group 2, and Group 3 were as follows: r = 0.725, r = 0.691, r = 0.855, and r = 0.611, respectively. The formula obtained by using Pearson's rank correlation coefficients to estimate log(e)AER from log(e)UAI in 123 cases of Groups 1-3, 67 cases of Group 1, 40 cases of Group 2, and 16 cases of Group 3 were: log(e)AER/log(e)UAI = 0.815, log(e)AER/log(e)UAI = 0.860, log(e)AER/log(e)UAI = 0.830, log(e)AER/log(e) = 0.722, respectively. In the present study, log(e)UAI was found to correlate well with log(e)AER. As AER is generally accepted to be the most reliable index to know the stage of albuminuria, UAI is considered to be clinically useful.