Determination of alpha 2-plasmin inhibitor in body fluids.

A sensitive method was developed to determine alpha 2 PI at very low concentrations. The minimal measurable concentration of alpha 2 PI was 0.5 ng/assay tube. Using this method, the alpha 2 PI in plasma, urine, amniotic fluid and cerebrospinal fluid was estimated. The mean values and standard deviation for plasma were 5.63 +/- 1.34 mg/dl in 25 males, and 5.29 +/- 1.62 mg/dl in 8 females; in the urine, 0.46 +/- 0.41 microgram/dl in 82 male samples, and 0.69 +/- 0.27 microgram/dl in 8 female samples; in amniotic fluid, 4.13 +/- 2.38 micrograms/dl in 16 samples; and in cerebrospinal fluid, 24.4 +/- 6.6 microgram/dl in 9 samples. The alpha 2 PI level in amniotic fluid was not correlated with the state of the pregnant mother, with that of the baby, or with the protein content or pH of the amniotic fluid.