The amount of antigen used per test is determined by diluting the material derived above until a total
fluorescence intensity of 250,000–300,000 is achieved using the FPM.
The antigen can be stored as a liquid for several years at 4°C in a dark bottle or it may be freeze dried in
dark bottles.
Small quantities of labelled antigen for research and standardisation purposes and standard operating
procedures for antigen preparation and the FPA may be obtained (see footnote 3 for address).