A laboratorian's perspective on evaluation and implementation of new laboratory tests.

New assay development should be directed toward answering fundamental clinical questions. Caveats that must be considered before initiating assay development projects are: New assays should allow the clinician to interact with and treat a patient more effectively, thereby improving medical outcome; and new assays should facilitate recapture of system resources, enabling cost savings or reinvestment of resources. Defining the clinical questions and consideration of the caveats permit a means of prioritizing assay development activities. Laboratorians are faced with evaluating several types of development activities that lead to assay implementation in routine clinical testing. Assays can be prioritized for up-grading to newer cost-effective technologies, provided the changes maintain or improve analytical and clinical performance. Predicting which research assay will have future value is difficult when clinical performance is not fully validated. However, such assay development has the greatest potential for changing the delivery of healthcare by a clinician.