Why physicians don't pursue abnormal laboratory tests: an investigation of hypercalcemia and the follow-up of abnormal test results.

For unknown reasons, physicians often ignore unsolicited clinical data. This is thought to impair the quality of medical care and the efficacy of screening programs. To investigate this problem the authors followed 156 consecutive hypercalcemic patients for nine to 15 months. Twenty-eight were lost to follow-up, and the hypercalcemia was ignored in 26. Calcium tests were repeated for 102, and hypercalcemia was confirmed in 53. Of these, 39 were and 14 were not further investigated. Analysis by logistic regression revealed a highly significant relationship between the degree of hypercalcemia and the likelihood that calcium testing would be repeated or that abnormal levels would be further investigated. The authors conclude that, contrary to common opinion, when physicians ignore abnormal laboratory values they are making complex clinical judgments based on the degree of abnormality, the likelihood that further investigation will affect therapy, and the cost of the risk associated with further investigation. Evaluation and attempts to modify this behavior should take into account the complexity of these decisions.