For the purposes of examination, a "use" claim in a form such as "the use of substance X as an insecticide" is regarded as equivalent to a "process" claim of the form "a process of killing insects using substance X". Thus, a claim in the form indicated is not to be interpreted as directed to the substance X recognisable (e.g. by further additives) as intended for use as an insecticide. Similarly, a claim for "the use of a transistor in an amplifying circuit" is equivalent to a process claim for the process of amplifying using a circuit containing the transistor and is not to be interpreted as being directed to "an amplifying circuit in which the transistor is used", nor to "the process of using the transistor in building such a circuit". However, a claim directed to the use of a process for a particular purpose is equivalent to a claim directed to that very same process (see T 684/02).

Care is to be taken when a claim relates to a two-step process which combines a use step with a product production step. This may be the case e.g. when a polypeptide and its use in a screening method have been defined as the only contribution to the art. An example of such a claim would then be:

"A method comprising:

Many variations of such a claim are conceivable, but in essence they combine (a) a screening step (i.e. using a specified test material to select a compound having a given property) with (b) further production steps (i.e. further transforming the selected compound for instance into the desired composition).

According to decision G 2/88 there are two different types of process claim, (i) the use of an entity to achieve a technical effect and (ii) a process for the production of a product. G 2/88 makes clear that Art. 64(2) applies only to processes of type (ii). The above claim and its analogues thus represent a combination of two different and irreconcilable types of process claim. Step (a) of the claim relates to a process of type (i), step (b) to a process of type (ii). Step (b) builds on the "effect" achieved by step (a), rather than step (a) feeding into step (b) a specific starting material and resulting in a specific product. Thus, the claim is made up partly of a use claim and partly of a process for producing a product. This renders the claim unclear according to Art. 84.