© 2019 Cleveland Clinic. The complete blood cell count (CBC) is one of the most frequently ordered laboratory tests, but some values included in the test may be overlooked. This brief review discusses 3 potentially underutilized components of the CBC: the red blood cell distribution width (RDW), the mean platelet volume (MPV), and the nucleated red blood cell (NRBC) count. These results have unique diagnostic applications and prognostic implications that can be incorporated into clinical practice. By understanding all components of the CBC, providers can learn more about the patient's condition.