Purpose of review: It is 20 years since the 10 Warning Signs of primary immunodeficiency (PID) were first published and with over 180 PIDs now identified it is timely to evaluate their effectiveness, given the broadening clinical spectrum of PID.
Recent findings: Two recent studies have sought to define the features that best identify patients with PID and compare these with the 10 Warning Signs. They suggest the 10 Warning Signs discriminate poorly between those with and without PID, and that other features identify about one-third of patients with PID in whom none of the 10 Warning Signs was present. Recent literature describes the diverse presenting features that may assist in more accurately identifying those with PID.
Summary: Further development and refinement of early warning signs in light of the growing knowledge of how PIDs manifest clinically may allow relatively simple yet effective guidelines targeted at different groups to better detect PID.