[Comparative study between artificial xenodiagnosis performed immediately and four hours after venous punch]

Artificial xenodiagnosis was performed immediately after blood venous punch and then four hours later on 63 patients; 29 (46%) were male and 34 (54%) female, mean age 39 years (range 18 to 68 years). Eleven (17.5%) patients presented positive exams, of which eight (12.7%) were from immediate xenodiagnosis and 7 (11.1%) xenodiagnosis four hours after. Eight patients showed 17 positive pools from immediate xenodiagnosis and 7 patients with xenodiagnosis four hours later showed 11 positive pools (p = 0.34). Four patients were positive only on immediate xenodiagnosis, three only on xenodiagnosis 4 hours after and four were positive in both. The data demonstrate that xenodiagnosis can be performed up to four hours after blood collection without impairing the test results.