Human a , - microglobulin levels in various body fluids

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 renal failure, however, were greatly increased, mean levels being 231*5 mg/i and 100 7 mg/24 h urine volume, respectively. Serum a,-microglobulin levels in these patients correlated well with both serum creatinine and P2-microglobulin levels. Serum a,-microglobulin level did not correlate positively with serum levels of other plasma proteins, such as a,-antitrypsin, haptoglobin, complement, etc. Ouchterlony immunodiffusion also revealed the presence of a,-microglobulin in synovial fluid, ascites, pleural effusion, amniotic fluid, cyst fluid, and cerebrospinal fluid. The levels of a,-microglobulin in these fluids were measured by single radial immunodiffusion, except that its level in cerebrospinal fluid was measured by radioimmunoassay. Mean a,-microglobulin concentration was 20-8 mg/i in synovial fluid, 28-7 mg/i in ascites, 21-5 mg/i in pleural effusion, 2-7 mg/i in amniotic fluid, 8-2 mg/i in cyst fluid, and 42-3 ng/ml in cerebrospinal fluid.