Evaluation of a prototype Trypanosoma cruzi antibody assay with recombinant antigens on a fully automated chemiluminescence analyzer for blood donor screening.
BACKGROUND
Chagas disease is caused by Trypanosoma cruzi, a protozoan parasite that can be transmitted by transfusion. The diagnosis of chronic T. cruzi infection is generally made by detecting specific antibodies that bind to parasite antigens. The aim of this study was to assess the sensitivity and specificity of a new serologic assay for antibodies to T. cruzi on a fully automated analyzer (PRISM, Abbott Laboratories).


METHODS
A prototype chemiluminescent immunoassay based on chimeric recombinant antigens and run on the automated PRISM system was developed for detecting antibodies to T. cruzi in human serum and plasma. Assay specificity was evaluated by testing samples from random blood donors and from a diverse group of specimens from persons with diseases or conditions often associated with false-positive reactions in T. cruzi assays. Sensitivity was determined by testing 377 geographically diverse T. cruzi antibody-positive specimens.


RESULTS
Six of 7911 samples (0.08%) from random donors were repeatedly reactive in the prototype PRISM Chagas assay. One of these was reactive in three other tests, including the radioimmune precipitation assay and was presumed to be a true positive. Hence, the specificity was 99.94 percent (7905/7910) in the negative donor group studied. All 377 T. cruzi antibody-positive specimens were positive in the prototype assay and thus the sensitivity was 100 percent.


CONCLUSIONS
The results obtained to date, in terms of sensitivity as well as specificity, strongly suggest that the PRISM Chagas assay should function well as a tool for screening blood for serologic evidence of T. cruzi infection.
Chang
Chi-Deu
CD
Emerging Pathogens R&D, Abbott Diagnostics Division, Abbott Laboratories, Abbott Park, Illinois 60064, USA.
Cheng
Kevin Y
KY
Jiang
Lily X
LX
Salbilla
Vince A
VA
Haller
Alla S
AS
Yem
Alex W
AW
Bryant
Jane D
JD
Kirchhoff
Louis V
LV
Leiby
David A
DA
Schochetman
Gerald
G
Shah
Dinesh O
DO
D000818:Animals; D000913:Antibodies, Protozoan / Q000737:chemistry* / Q000235:genetics / Q000276:immunology; D001782:Blood Donors; D014355:Chagas Disease / Q000097:blood* / Q000235:genetics / Q000276:immunology; D046148:Donor Selection / Q000379:methods; D006801:Humans; D007118:Immunoassay / Q000379:methods; D008163:Luminescent Measurements / Q000379:methods; D011994:Recombinant Proteins / Q000737:chemistry / Q000235:genetics / Q000276:immunology; D012680:Sensitivity and Specificity; D014349:Trypanosoma cruzi / Q000737:chemistry / Q000235:genetics / Q000276:immunology
D000913:Antibodies, Protozoan; D011994:Recombinant Proteins