Yes. Immunosuppressant medications may suppress levels of Total IgE, thus influencing the total IgE antibody response to a particular antigen, causing falsely lowered or false negative IgE results. If immunosuppressant medication cannot be discontinued prior to testing, it is recommended to test Total Immunoglobulins prior to ordering antibody-based tests.
Critical analysis is required to assess validity and utility of results. The key determinant is to assess for variability in test results. If Total Immunoglobulins are low and most/all antigen-specific levels are normal or low end of normal range, suspect interference. If Total Immunoglobulins are low and some antigen-specific levels are normal while some are moderately elevated and others are positively elevated, interpret moderate/positive results as likely true antigen-antibody reaction.
