Which of the following is a common laboratory finding in neonatal sepsis?

Neutropenia is a common laboratory finding in neonatal sepsis, primarily because sepsis can lead to a diminished production of neutrophils due to the overwhelming infection that the newborn's immune system is attempting to combat. In neonates, particularly in those who are ill, there can be a shift in the bone marrow response, where neutrophil production may not keep pace with the demand created by the infection. This results in a lower than normal count of neutrophils in the blood, making neutropenia an indicator of serious bacterial infection in newborns.

In the context of neonatal sepsis, leukocytosis is often not observed, as infants may not have an adequate immune response in the face of severe infection. Thrombocytosis would suggest a reactive process, but in sepsis, thrombocytopenia can often be observed due to consumption coagulopathy and platelet activation rather than an increase in platelet count. Polycythemia, or increased red blood cell mass, is not typically associated with infection and is more usually related to other conditions such as intrauterine stress or hypoxia in the fetus. Thus, the observation of neutropenia is significant in diagnosing and managing suspected cases of neonatal sepsis.