Technique

272394005 | Technique (qualifier value)|

A technique (also called method) is a particular way of performing an activity or task.

While a technique describes how a specific observation is performed, it should generally not include specific details about what is being observed, i.e., it should not include a component, specimen type, body site, etc. 

Information about what is being observed would be included in a separate attribute of the Observable entity model. The Observable Entity Defining Attributes page provides more details about modeling of observables using various attributes.