Screening of neonatal thyroid disease is done by

Since the neonates are asymptomatic at bih all newborns are screened for neonatal hypothyroidism. TSH is estimated either in cord blood at the time of bih (preferred) or blood obtained from heel prick after 2 days of bih.(Refer: Nelson's Textbook of Pediatrics, SAE, 1st edition, pg no. 2669 - 2773)