A 9-month-old infant is brought to the clinic for a routine…
A 9-month-old infant is brought to the clinic for a routine check-up. The child was born full-term and has had no major illnesses. Growth chart review reveals a consistent drop from the 50th percentile at birth to below the 5th percentile for weight over the past few months, while length and head circumference remain in the 25th percentile. The mother reports the baby eats small amounts, is frequently irritable, and has 3–4 loose stools per day. Which of the following is the most appropriate next step in the evaluation of this child with suspected Failure to Thrive?