Positive malaria rapid test in asymptomatic blood donor – Undetectable parasitemia or false positive?

Abstract

A 35-year-old male, first-time whole blood donor, cleared for donation by physical examination and donor questionnaire, tested reactive for malaria by rapid diagnostic test (RDT). Tests done in triplicate with bag segment samples gave the same results. He had no history of travel to endemic areas or of features suggestive of or a confirmed diagnosis of malaria or its treatment. There was also no history of any prolonged illness or medications. Repeat physical examination was unremarkable, he had no history of fever postdonation and repeat samples showed a normal hemogram, negative for malaria parasite by thick and thin smears and RDT. Further work-up, such as nucleic acid testing or quantitative polymerase chain reaction, was not done due to financial constraints and nonsuggestive history, physical examination, and laboratory tests. The unit was discarded, however, since asymptomatic, low-dose parasitemia could not be ruled out, it could not be definitively labeled false positive.

Keywords

• asymptomatic donor
• malaria
• rapid diagnostic test