It is difficult for unaided physicians to keep up with the scientific advances and changing practice guidelines relevant to ordering and interpreting laboratory tests. Overordering, underordering, and misordering of tests are all common, and specific practices vary tremendously from community to community. Pathologists and clinical laboratory scientists have valuable knowledge that can help treating physicians provide higher-quality and more cost-effective care. Laboratorians can use online test catalogs to steer physicians toward optimal test algorithms, with hyperlinking to journal articles, clinical guidelines, and other reference materials. Retrospective audit of ordering patterns can efficiently pinpoint educational needs specific to a physician community.