The Complete Blood Count

THE COMPLETE BLOOD COUNT (CBC) is one of the more common laboratory tests ordered during the neonatal period. The CBC may be obtained to evaluate for anemia, infection, and thrombocytopenia.¹ The test offers a wealth of clinical information about the hematopoietic system, including erythrocyte, leukocyte, and thrombocyte values. Establishing normal neonatal ranges has been difficult because blood has not been drawn on healthy neonates of similar ages.² Reference ranges that consist of the 5th to 95th percentile compiled from various studies have been used to approximate normal neonatal values.³ A variety of factors such as sample site, timing of the sample, gestational age, and the neonate’s degree of health can affect the CBC.¹ Therefore, the astute practitioner must be able to recognize the clues and nuances of the CBC to guide the diagnostic assessment.⁴