What laboratory value might indicate dehydration in a 2-month-old infant with rotavirus?

A hematocrit of 51% is indicative of dehydration, particularly in the context of a 2-month-old infant with rotavirus, which can lead to significant fluid loss through diarrhea and/or vomiting. In a well-hydrated state, a normal hematocrit level for an infant would typically be around 30% to 40%. When dehydration occurs, the percentage of red blood cells in the total blood volume increases, leading to a higher hematocrit value.

In this situation, a hematocrit of 51% signifies that the infant's blood volume is relatively concentrated due to a lower volume of plasma, which is lost as a result of dehydration. This laboratory finding helps healthcare providers assess the severity of the infant's hydration status and guides further treatment to replace lost fluids.

Understanding normal hematocrit levels and how they change in response to dehydration is crucial for recognizing potential health concerns in pediatric patients, especially in cases of gastroenteritis caused by infections like rotavirus.