Laboratory detection of donors implicated in transfusion-transmitted malaria.

BACKGROUND

Transfusion-transmitted malaria (TTM) is rare in non-endemic areas (non-EAs) but can potentially be fatal. This review analyzes the laboratory results of donors causing TTM in non-EAs, to assess the detectability of their Plasmodium infection by molecular or antibody tests.

STUDY DESIGN AND METHODS

TTM cases in the United States, Canada, and Europe since 2010 were identified through a literature review. Authors and laboratories were contacted for missing details about sample types and laboratory methods. Results of Plasmodium polymerase chain reaction (PCR) and antibody tests were summarized.

RESULTS

Twelve cases of TTM and one bone marrow transplant transmission were identified. Of the 13 source donors, 12 were tested by PCR, 10 were positive on at least one sample; the 2 negative donors were tested only on retained segments of blood refrigerated for several weeks. All donors were PCR positive on a fresh sample except one who was positive on a retained but not a fresh sample. These PCRs targeted Plasmodium DNA with sensitivities in the range of 1000-10,000 parasites/mL. Antibody EIA was positive in only three of seven donors tested.

DISCUSSION

This review found that antibody EIAs failed to detect four of the seven TTM donors tested. DNA-based PCRs were able to detect Plasmodium infection in all donors tested except for two tested only on samples likely to have deteriorated from prolonged storage. Recently developed ribosomal RNA-based molecular donor screening assays are approximately 1000 fold more sensitive than these DNA-based PCRs, holding promise as a potential method to further reduce TTM.