When using the MP/H rules, what must the registrar do first?

When using the MP/H (Multiple Primary and Histology) rules, the first step a registrar must take is to be familiar with the General Instructions. Understanding these instructions is crucial because they provide the framework and foundational knowledge needed for applying the rules correctly. The General Instructions guide the registrar on how to interpret and apply the subsequent rules, ensuring that the data recorded are accurate and consistent.

Familiarity with the General Instructions encompasses knowledge about definitions, the structure of the MP/H rules, and the specific situations to which they apply. This foundational understanding ensures that a registrar can navigate complex cases involving multiple primaries or varying histologies without confusion.

Using the Multiple Primary Rules, Equivalent Terms and Definitions, or Histology Rules are all important steps in the process, but they come after one has a solid grasp of the General Instructions. Without this foundational knowledge, a registrar may misinterpret the rules or misapply them, leading to inaccuracies in cancer registry data.