Repeated Spurious Elevation Of Serum Prostate-Specific Antigen Values Solved By Chemiluminescence Analysis: A Possible Interference By Heterophilic Antibodies

Heterophilic antibodies are human immunoglobulins directed against various animal antigens. They can produce false-positive results in the analysis of different tumor markers, including prostate-specific antigen. This interference can lead to misdiagnosis, unnecessary tests, and overtreatment in some cases. We present herein the case of a 52-year-old man with repeated spurious elevation of prostate-specific antigen, reaching levels of 108.7 ng/mL, that were suspected to be caused by heterophilic antibodies. The interference was solved by changing the analysis technique. Real values of prostate-specific antigen were less than 1 ng/mL.