To test or not to test

[One of the authors responds:]

Roland Jung raises important questions. Neither the Canadian Society of Nephrology nor the Canadian Task Force on Preventive Health Care has issued a directive about whether serum creatinine testing should or should not be included as part of periodic health examinations. Certainly, widespread population screening is not what we are advocating.

Many physicians perform serum creatinine testing as part of a routine panel of biochemical tests, which may be ordered for many different reasons. The guidelines do suggest a case-finding approach in describing characteristics of patients at high risk for renal failure, in whom serum creatinine should be tested. The guidelines are meant to recommend what should happen when an elevated serum creatinine level is discovered in these settings.

The question about frequency of testing is a difficult one to answer. It was considered by the committee but was not included in the guidelines because there are so many factors that must be considered. For example, annual or biannual testing is sufficient if a patient has mild, chronic and relatively nonprogressive renal failure, whereas monthly testing might suffice for a patient with severe chronic renal failure. Weekly or even daily testing might be required for a patient with rapidly progressive glomenulonephritis.