What diagnostic tests to order for viral infections in patients with CVID? Are antibody-based tests OK?

Question:

A 64-year-old female with Common Variable Immune Deficiency (CVID) has cirrhosis. The suspected diagnosis is nonalcoholic steatohepatitis but the treatment team would like to rule out chronic viral hepatitis.

How reliable is antibody testing in patients with CVID. i.e. in this patients workup, would a negative hepatitis B core antibody test be trustworthy? Would you just do viral loads if you were really concerned? Does receiving IVIG effect the tests?

Answer:

You need to order the PCR tests for the antigens (not the antibodies) to be assured the results are valid. The administration of IVIG affects the results of the diagnostic Ab tests.

References:

Appropriate assay for human immunodeficiency virus and hepatitis C in patients with common variable immunodeficiency disorders. AAAAI.

Image source: Diagram of HIV. Image source: Wikipedia.