What is already known about this topic?

IEIs are inherited disorders characterized by an increased susceptibility to life threatening infectious diseases, autoimmunity, and malignant diseases with a high mortality rate in the first years of life.

What does this article add to our knowledge?

Twenty years after the introduction of NBS for primary immunodeficiency we report on an expanded NBS program for IEIs. The program increased our diagnostic rate and consequentially improved care for patients and their families.

How does this study impact current management guidelines?

All patients with an IEI benefit from early management. An expanded NBS strategy has the potential to enhance diagnostic accuracy for IEIs and potentially reduces delays in introducing treatment.