Malarial antibodies in Auckland blood donors
Davidson, N.; Woodfield, G.; Henry, S.
New Zealand Medical Journal 112(1088): 181-183
1999
ISSN/ISBN: 0028-8446 PMID: 10391642 Document Number: 500446
530 blood donors in Auckland, New Zealand were identified according to standard protocols as being at risk of malaria infection, having visited a malarious area within the previous 3 years; they were questioned as to their degree of exposure to malaria, and blood samples were tested for malarial antibodies using an enzyme immunoassay kit which detects IgG antibodies to Plasmodium falciparum and shows 50% cross-reactivity with P. vivax and some cross-reactivity with P. ovale. Antibody positive samples were further checked by a direct immunochromatographic test for P. falciparum. Nine (1.7%) of the donors who were classified as a "malarial risk" were positive for IgG malarial antibodies, but none of these antibody-positive samples were positive by the direct immunochromatographic test for P. falciparum. These results indicate that none of these donors tested were at risk of transmitting P falciparum, the major and most serious cause of transfusion-transmitted malaria. It is concluded that testing of malarial risk blood donors in Auckland, who are currently used for plasma donation only, could, by identifying donors who do not constitute a risk, potentially make available 2300 units of red cells per year (about 4% of all collected blood) which cannot currently be used.