a,-Microglobulin levels in serum and urine were estimated by using single radial immunodiffusion, resulting in the following mean values: umbilical cord blood serum, 40*6 mg/I; normal adult serum, 44-2 mg/I; and normal urine, 5 7 mg/24 h urine volume. Slightly higher levels of serum a1-microglobulin were found in infants and the aged. Serum and urine a,-microglobulin levels in patients with ren...