In the case law of the boards of appeal a distinction is made in the approach to methods for treatment by surgery or therapy on the one hand and diagnostic methods on the other. The leading cases are G 1/04 (OJ 2006, 334) concerning diagnostic methods, and G 1/07 (OJ 2011, 134) concerning treatment by surgery.

An important difference between the two approaches is that, whilst a method claim falls under the prohibition on patenting methods for treatment by therapy or surgery if it comprises or encompasses at least one feature defining a physical activity or action that constitutes a method step for treatment of a human or animal body by surgery or therapy (G 1/07), a much narrower interpretation of Art. 52(4) EPC 1973 was applied with regard to the exclusion from patentability of diagnostic methods in G 1/04 (see in this chapter I.B.4.5. "Diagnostic methods" – G 1/04).