The American National Standards Institute (ANSI) approved the latest version of the Health Level Seven (HL7) Arden Syntax for Medical Logic Systems. This version was prepared by members of Medexter Healthcare, discussed in the Arden Syntax Work Group of HL7 International, and successfully balloted by the HL7 community. Through the integration of fuzzy sets and fuzzy logic, this new and augmented version of the Arden Syntax is able to include linguistic and propositional uncertainty into the medical knowledge representation.