For an infant presenting with vomiting and lethargy, what would be a crucial finding during evaluation?

In cases involving an infant with vomiting and lethargy, a poor feeding history is indeed a crucial finding. This can indicate a significant underlying issue, as infants typically require frequent feedings for appropriate growth and energy levels. A poor feeding history can suggest dehydration, decreased energy due to illness, or gastrointestinal issues that could directly contribute to vomiting and lethargy. It provides important clues regarding the infant's overall health status and helps guide further evaluation and management.

While other findings may also provide useful information, they do not carry the same weight in indicating a potentially critical condition in this context.