[Consideration on the King-Armstrong method and on the kinetic method for the measurement of the alkaline phosphatase activity in serum (author's transl)].

The comparative study of a determined time method, according to King-Armstrong, for the measurement of the alkaline phosphatase activity in serum and of a kinetic method consents us to make the following points: 1) the reagents used in the King-Armstrong method are easily prepared and are stable for months, with the sole addition of cloroform to the substrate and to the buffer to avoid the growth of moulds. 2) The substrate used for the kinetic method undergoes spontaneous Xydrolysis in acqueous solution, which makes it possible to keep it refrigerated for a limited number of days. Freezing at - 20 degrees C does not improve the situation. 3) The degree of precision within the series and between the series is the same for the two methods, and very good. 4) From the working point of view the method of "determined time" is advantageous for few samples, while the kinetic method becomes preferable when the number of samples goes over 20 and 30 a day, provided that it is linked with the suitable automatic apparatus. 5) The results of the measurement of the enzyme activity found with the two methods on 120 sera of normal and pathological subjects have shown good correlation, confirming the clinical diagnostic value of the results obtained by the kinetic method, which uses a transphosphorilant buffer and their congruency with those obtained by the classical King-Armstrong method.