The phosphatase test of Aschaffenburg and Mullen: Use of permanent colour standards and comparison with the Kay-Graham test

A method has been developed for measuring the intensity of colour produced in the Aschaffenburg & Mullen phosphatase test in which use is made of permanent colour standards. 2. Using this method, the relationship between this phosphatase technique and the official Kay-Graham test has been investigated. 3. The limiting standards corresponding to 2.3 Lovibond Blue Units in the KayGraham test have been established for the 30 min. and 2 hr. procedures of Aschaffenburg & Mullen. 4. The advantages of the improved technique of the Aschaffenburg & Mullen test are discussed.