[Measuring the activity of the placental isoenzyme of alkaline phosphatase: 3 methods compared (author's transl)].

Three methods were compared in human serum for determining the activity of the placental isoenzyme of alkaline phosphatase: 1. Heat inactivation at 65 degrees C for 10 minutes, 2. Differential inactivation with L-p-Bromotetramisole, and 3. an immunological precipation test. A good comparison between the three methods was found (correlation coefficient between 0.973 and 0.982). For long series or screening determinations for "Regan-isoenzyme" the differential inactivation with L-p-Bromotetramisole is preferred because of the short analysis time and the possibility of simple mechanisation.