A complement fixation test (CFT) has been used for ninety years to diagnose T. cruzi infection. It is heralded for its low cost and high efficiency, however it is quite labor intensive and requires skilled technicians. In 1994 a simplified version of the CFT became available, which reduced the amount of labor required for the test without sacrificing accuracy (92% sensitivity and 99% specificity have been demonstrated with the new test.)
(Garcia, E, Ramirez, LE, Monteon, V, and Sotelo, J. Diagnosis of American Trypanosomiasis (Chagas’ Disease) by the New Complement Fixation Test. Journal of Clinical Microbiology. 1195. 33(4); 1034-1035.)
Identification of motile trypanosomes in the peripheral blood, through study of a blood smear stained with Giemsa, is another common way in which T. cruzi infection is diagnosed.
Finally, xenodiagnosis is used in which laboratory-raised, uninfected triatomine bugs are allowed to bite the patient for several hours then, four weeks later, the contents of the bug’s gut is examined for signs of the parasite.
Xenodiagnosis using a small tin containing clean triatomine bugs