Clin Diagn Lab Immunol 7 (2): 131 - 140, 2000. doi: 10.1128 / cdli.7.2.131 - 140.2000 Diagnosis Clinical evaluation Sometimes gene testing Diagnosis of hyper-IgD syndrome is based on history, examination, and a serum IgD level of > 100 units / L; however, up to 20% of patients have normal serum IgD levels.