Table 1.

When to initiate IgG-RT.

2022 AAAAI Work Group Report for Secondary HG	• IgG < 400 mg/dL with recurrent infections • IgG < 700 mg/dL with recurrent infections, in addition to low IgA or IgM, and impaired vaccine responses • IgG < 150 mg/dL
HCT guidelines	• Not routinely recommended, but can be considered if IgG <400 mg/dL
ASBMT	• Recommend against IgG-RT if no history of recurrent infection, regardless of IgG level
Hill et al.	• Check serum IgG prior to and within 3 months post-CAR T cell therapy and consider if IgG is ≤400 mg/dL • IgG 400–600 mg/dL with serious recurrent infections • IgG > 600 mg/dL with impaired vaccine responses