The Duesseldorf warning signs for primary immunodeficiency: is it time to change the rules?

Different sets of warning signs can be used if primary immunodeficiency (PID) is suspected: those of the Jeffrey Modell Foundation (JMF), the German Patients' Organisation for Primary Immunodeficiencies (DSAI) and the Association of the Scientific Medical Societies in Germany (AWMF). A few studies have tested the JMF criteria, with unconvincing results, but the diagnostic models of the DSAI and AWMF have not been tested at all. We set out to establish the utility of these three scoring systems and compare them with our own set of five warning signs (Duesseldorf criteria).

Prospective study.

Two hundred ten patients admitted to our hospital between 2010 and 2012 with suspected PID.

PID were found in 36 (17 %) of the patients admitted. Of the established sets of warning signs, the JMF and the DSAI had inadequate sensitivity, while the DSAI and the AWMF showed insufficient specificity. Our own criteria were analyzed with regard to maximal specificity and sensitivity (Youden Index) and sensitivity and yielded NPV of 0.89 and 0.91 respectively. Youden index revealed combination of five signs and symptoms: lymphopenia, otitis media >7, failure to thrive, failure to grow normally, pneumonia >1. For maximum negative predictive value the following set was found: lymphopenia, hypogammglobulinemia, failure to thrive, growth disorders, iv antibiotics and abscesses.

In contrast to the new, evaluated Duesseldorf criteria, all three established sets of warning signs proved inadequate for preselection of patients for admission to specialized PID centers. The Duesseldorf criteria should now being tested in further studies.