An 8-month-old girl is brought to the office for evaluation of inadequate weight gain. Her mother reports the infant is breastfed on demand but seems uninterested in feeding and often falls asleep after a few minutes. The family recently moved and the mother admits to feeling overwhelmed and isolated. Birth weight was 3.2 kg (50th percentile). Current weight is 6.0 kg (below 5th percentile for age). Physical examination shows a thin infant with decreased subcutaneous fat but no edema, organomegaly, or dysmorphic features. She is alert but does not smile readily. Which of the following is the most appropriate initial evaluation approach? Evaluation Component Specific Elements Priority History Feeding schedule, intake volume, formula preparation, caregiver stress, food insecurity High Physical Exam Signs of chronic disease (cardiac murmur, hepatomegaly), skin changes, developmental assessment High Initial Labs CBC, comprehensive metabolic panel, urinalysis, thyroid function Medium Specialized Testing Sweat chloride, celiac panel, imaging studies Low (if above unrevealing)