» Histoplasmin conforms to the regulations of the FDA concerning biologics (see
Biologics
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). It is a clear, colorless, sterile solution containing standardized culture filtrates of
Histoplasma capsulatum grown on liquid synthetic medium. It has a potency of the 1:100 dilution equivalent to and determined in terms of the Histoplasmin Reference diluted 1:100 tested in guinea pigs. It may contain a suitable antimicrobial agent.