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symbolB.1 General prohibition symbolThe general prohibition symbol (as used in ISO 3864-1) is intended to indicate a prohibited action. For medical device labelling, the prohibition circle with a diagonal bar should be used to mean “do not”, e.g. symbol 5.4.2 “Do not re-use”. It is sometimes used out of context in medical device labelling, e.g. to mean “does not contain”. It is important that usage be consistent with the intended meaning so that hazards do not arise from misunderstanding.B.2 Negation symbolManufacturers wishing to communicate the meaning “does not” or “is not” where a symbol expressing this meaning does not exist, should follow the method set out in IEC 80416-3:2002, Clause 7 (a large “X” placed over the symbol). Although it is not generally recommended that this symbology be used with any of the symbols given in this document, the use of the negation symbol is permitted.

[1] ISO 3864-1, Graphical symbols — Safety colours and safety signs — Part 1: Design principles forsafety signs and safety markings[2] ISO 7010, Graphical symbols — Safety colours and safety signs — Registered safety signs[3] ISO 14971, Medical devices — Application of risk management to medical devices[4] ISO 18113-1, In vitro diagnostic medical devices — Information supplied by the manufacturer(labelling) — Part 1: Terms, definitions and general requirements[5] ISO 18113-22), In vitro diagnostic medical devices — Information supplied by the manufacturer(labelling) — Part 2: In vitro diagnostic reagents for professional use[6] ISO 18113-33), In vitro diagnostic medical devices — Information supplied by the manufacturer(labelling) — Part 3: In vitro diagnostic instruments for professional use