A 50-year-old male patient admitted to the hospital with renal insufficiency, anaemia, monoclonal protein (IgG kappa) and uremic encephalopathy was screened for malaria due to increasing serum CRP-levels and neurological decline combined with an indistinct travel history. The malaria rapid diagnostic test (RDT) revealed a positive result; however, no malaria parasites were detected by the pathologist through microscopic evaluation of the thick and thin blood smear. Additional tests were performed to investigate potential causes of the false positive malaria RDT such as the presence of heterophilic antibodies, the monoclonal protein and rheumatoid factor. This case presented a false positive malaria RDT result due to a confirmed interference of heterophilic antibodies. The interference could be omitted using a heterophilic antibody-blocking agent.

(BELG J HEMATOL 2023;14(8):343–6)