Worldwide Recall Rate in Newborn Screening Programs for Congenital Hypothyroidism

Neonatal mass screening program for congenital hypothyroidism provides the best tool for prevention of its devastating effects on mental development. Despite the overall success of the screening programs in detecting congenital hypothyroidism and eliminating its sequelae and new developments made in the program design, high recall rate and false positive results impose a great challenge worldwide. Lower recall rate and false positive results may properly organize project expenses by reducing the unnecessary repeated laboratory tests, increase physicians and parents' assurance and cooperation, as well as reduce the psychological effects in families.

In this review, we assessed the recall rate in different programs and its risk factors worldwide.

Publications reporting the results of the CH screening program from 1997 to 2016 focusing on the recall rate have been searched.

Recall rates vary from 0.01% to 13.3% in different programs; this wide range may be due to different protocols of screening (use of T4 or TSH or both), different laboratory techniques, site of sample collection, recall cutoff, iodine status, human error, and even CH incidence as affected by social, cultural, and regional factors of the population.

It is suggested to implement suitable interventions to reduce the contributing factors by improving the quality of laboratory tests, selecting conservative cut off points, control iodine deficiency, use of iodine free antiseptic during delivery, and use of more specific markers or molecular tests. Applying an age dependent criteria for thyrotropin levels can be helpful in regions with a varied time of discharge after delivery or for preterm babies.