Does review of peripheral blood smears help in the initial workup of common anemias?

Sixty-five physicians were tested to determine the effect of their reviews of red blood cell morphology on their subsequent diagnoses of and workup plans for common anemias. The subjects read clinical and laboratory data for six pairs of cases of anemia, reviewing the blood smear for one case in each pair. They correctly identified the presence or absence of morphologic features on the blood smears 82% of the time. In spite of excellent morphologic discrimination, the number of tests ordered was not affected by blood smear review. In fact, the quality of the physicians' workup plans, measured by numbers of tests appropriately ordered and excluded, was slightly but significantly better when they did not review the smears (p less than 0.005). In addition, smear review did not significantly improve diagnostic accuracy for any of the common anemias studied. Significantly more correct diagnoses were made without smear review for vitamin B12-folate deficiency anemia (p less than 0.015) and thalassemia (p less than 0.0001). Although routine review of blood smears by physicians in the management of common anemias may provide useful information, the authors were unable to demonstrate an improvement in the number or appropriateness of tests ordered or diagnostic accuracy in spite of excellent morphologic discrimination.