Post-discharge growth of extremely low birth weight neonates.

‘Screening window’, defined as the period between the development of the abnormal test result of NBS and development of symptoms in the infant, may vary from disorder to disorder. It will be most ideal to collect sample on fourth day of life. Samples can be collected from home by trained nurse/phlebotomist. There are many riders associated with interpretation of blood samples collected in the first few days of life; often a repeat testing may be warranted. This not only increases the costs but can also lead to false alarm and cause panic in parents and families. However, defining age-appropriate cut-offs – as in the study in this issue of Indian Pediatrics [6] – may circumvent the problem of loss to follow-up. It is important to define criteria for permanent and transient hypothyroidism and exclude cases of transient hypothyroidism [7]. Workshops and pilot studies are required for standardization of diagnostic criteria for congenital hypothyroidism.