The correct answer is reticulocytes. They are immature red blood cells. which compose about 1% of the red blood cells in the human body. The reticulocyte counts are measured by using automated counters and the test is often reffered to as a rectic count.. The test is done by taking blood. Once this is done, the cells are counted and these counters combine detectors, fluorescent dye, and laser excitation, that mark it as either RNA or DNA. They stand out from other cells because they send off a signal that isn't strong or weak. Low reticulocyte numbers can cause vitamin deficiencies, anemia, and bone marrow malignancies.