Reducing unnecessary laboratory use with new test request form: example of tumour markers.

To limit the ordering of serum tumour marker tests that are clinically irrelevant, we designed a new request form. This is a matrix of boxes, rows being individual markers and columns body organs. The box at the intersection of line and column is colour-coded to indicate whether the test is appropriate or not. These ratings were allocated on the basis of published data and local consensus. This new form replaced the form in use at our hospital at the beginning of 1992, and resulted in a 25% decrease in the ordering of tumour markers. Adapting the design of the test request form is a low-cost intervention that combines both economic and clinical requirements in reducing the prescription of tests that are useless in a given clinical situation.