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Investigational screening for B abesia microti in a large repository of blood donor samples from nonendemic and endemic areas of the U nited S tates
Author(s) -
Moritz Erin D.,
Winton Colleen S.,
Johnson Stephanie T.,
Krysztof David E.,
Townsend Rebecca L.,
Foster Gregory A.,
Devine Patricia,
Molloy Philip,
Brissette Edward,
Berardi Victor P.,
Stramer Susan L.
Publication year - 2014
Publication title -
transfusion
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.045
H-Index - 132
eISSN - 1537-2995
pISSN - 0041-1132
DOI - 10.1111/trf.12693
Subject(s) - medicine , virology , polymerase chain reaction , confidence interval , antibody , biology , immunology , gene , genetics
Background B abesia microti, a transfusion‐transmissible intraerythrocytic parasite, is increasing in frequency in the U nited S tates with no available FDA ‐licensed donor screening assay. We utilized investigational arrayed fluorescence immunoassay ( AFIA ) and polymerase chain reaction ( PCR ) to detect B . microti antibodies and DNA in blood donors. Study Design and Methods AFIA and real‐time PCR were performed on frozen paired EDTA plasma ( AFIA ) and EDTA whole blood ( PCR ) samples collected from M ay to S eptember 2010 to 2011 in nonendemic ( A rizona [ AZ ] and O klahoma [ OK ]), moderately endemic ( M innesota [ MN ] and W isconsin [ WI ]), and highly endemic ( C onnecticut [ CT ] and M assachusetts [ MA ]) areas of the U nited S tates. AFIA utilized B . microti piroplasm as an antigen substrate; PCR primers and probes targeted the B . microti 18 S ribosomal RNA gene. Data from AZ and OK were used to calculate specificity. All AFIA ‐ or PCR ‐positive or ‐inconclusive donors were deferred, notified, and invited to participate in a follow‐up study involving repeat testing and a demographic and risk‐factor questionnaire. Recipient tracing was performed for any cellular component transfused at index, at subsequent donation, or within the prior 12 months. Results Testing of 13,269 paired samples included 4022 from AZ and OK , 4167 from MN and WI , and 5080 from CT and MA . B . microti antibody and/or DNA prevalences were 0.025% (95% confidence interval [ CI ], 0.00%‐0.14%), 0.12% (95% CI , 0.04%‐0.28%), and 0.75% (95% CI , 0.53%‐1.03%) in the nonendemic, mid‐endemic, and high‐endemic regions, respectively. Specificities were 99.95% (95% CI , 99.82%‐99.99%) at a 1‐in‐64 AFIA cutoff and 99.98% (95% CI , 99.86%‐100.00%) at a 1‐in‐128 cutoff. Conclusions B . microti prevalence followed expected geographical patterns. Screening was feasible with a performance comparable or superior to other infectious disease blood donor screening assays.