The spun hematocrit is a common screening test performed on normal newborn infants to determine anemia, and more commonly, polycythemia. Recently, the hemoglobin value obtained from the HemoCue system (HemoCue Inc.; Mission Viejo, Calif.) has gained popularity in the adult and outpatient pediatric population to screen blood for anemia. Although the machine is not in widespread use in hospitals, it is being used in blood banks and physician offices. The main advantage of using the HemoCue system versus a spun hematocrit is that specimen collection is safer. Universal precautions are used with all infants; however, a cut from a broken capillary tube places the health care worker at an increased risk of exposure to blood-borne pathogens. The HemoCue system is also a more rapid test that requires less blood. In addition, the machine is silent. This study was conducted to determine whether a hemoglobin values obtained with the HemoCue system could replace the spun hematocrit to screen for anemia and polycythemia in normal newborn infants. Fifty-four specimens were obtained from healthy, term newborn infants. The hematocrit and hemoglobin specimens drawn in the nursery and processed in the laboratory were compared. The hemoglobin was consistently one third the value of the hematocrit. There was a significant and systematic difference between the values obtained with the HemoCue in the nursery and the laboratory hematology analyzer. The HemoCue readings were slightly lower in all cases.(ABSTRACT TRUNCATED AT 250 WORDS)