Purpose of review: Genetic testing serves an increasingly important role in the diagnosis and management of primary immunodeficiency. In this review, the strengths and limitations of various genetic testing methods are summarized, providing a foundation for the clinical approach to achieving a molecular diagnosis.
Recent findings: Rapid advances in sequencing technology have enabled the incorporation of comprehensive genetic testing into first-line clinical diagnostics. Recent articles enable comparisons of the diagnostic utility of new testing strategies while simultaneously reminding clinicians of the strengths of traditional methods.
Summary: Genetic testing in primary immunodeficiency cannot be standardized, but instead needs to be personalized based on the presenting phenotype and a basic understanding of the utility of different molecular methods. These tools, when correctly employed, can achieve a molecular diagnosis and inform the natural history, prognosis, recurrence risk, and therapeutic options.