Trypanosoma cruzi (Chagas Disease) – Serology

Background
This page provides serologic testing information for Chagas disease at Public Health Ontario (PHO). The causative agent of Chagas disease is the parasitic hemoflagellate Trypanosoma cruzi.

Updates
This new test information page was published on October 10, 2025 and includes information that was previously found in Trypanosoma American or African-Serology.

*Uncontrolled print copy. Valid only on day of print: 10 Oct 2025.

Testing Indications

Trypanosoma cruzi serology should be considered for the diagnosis of individuals with clinical and epidemiological evidence of chronic Chagas disease. Serology should also be considered, along with microscopy and PCR, for the diagnosis of infants with suspected congenital Chagas disease.¹

Serological screening of asymptomatic individuals (including indeterminate Chagas disease form) may be a consideration for:

Women who have lived more than 6 months in endemic areas of Mexico, Central America, or South America, before or during pregnancy to reduce the risk of congenital infection
Individuals who have lived more than 6 months in endemic areas as above before transplantation to reduce the risk of Chagas reactivation
First-degree relatives of a person previously diagnosed with Chagas disease

For the diagnosis of acute Chagas disease, serology is not routinely recommended, instead refer to Trypanosoma cruzi (Chagas Disease) — Microscopy and PCR.

Acceptance/Rejection Criteria

T. cruzi serology will only be accepted in cases with any of the following documented:

Travel to a Latin American region (including Mexico, Central America, and South America)
Family history of known Chagas disease
Transplantation, transfusion, or congenital exposure

Failure to provide this information will result in test cancellation or testing delays.

Specimen Collection and Handling

Specimen Requirements

Test Requested

Required Requisition(s)

Specimen Type

Minimum Volume

Collection Kit

Trypanosoma cruzi or Chagas serology

General Test Requisition

Serum, or

Blood, clotted

1.0 ml

5.0 ml

Serum separator tube (SST), or

Plain or pro-coagulation tube

Submission and Collection Notes

Complete all fields of the requisition form.

Specify any of the following testing indications on the requisition. Failure to provide this information may result in rejection:

Documented travel history to a Latin American region
Family history of Chagas disease
Transplantation, transfusion, or congenital exposure

Label the specimen container(s) with the patient’s first and last name, date of collection, and one other unique identifier such as the patient’s date of birth or Health Card Number. For additional information see: Criteria for Acceptance of Patient Specimens. Failure to provide this information may result in test cancellation or testing delay.

Timing of Specimen Collection

Serology may be negative in the first 2 to 8 weeks following acute infection and is not recommended for the diagnosis of acute Chagas disease.

In cases of suspected congenital Chagas disease, serology may need to be repeated when the infant is 9 to 12 months of age to allow for interpretation without transferred maternal IgG antibodies.

Limitations

Grossly haemolysed, lipemic, contaminated specimens and specimens containing anti-coagulant are unsuitable for testing.

Storage and Transport

Centrifuge tube if using SST. Place specimen container in a biohazard bag and properly seal the bag. Specimens should be stored at 2–8°C and shipped to PHO on ice packs within 48 hours of collection. All specimens must be shipped in accordance to the Transportation of Dangerous Good Act.

Requisitions and Kit Ordering

Test Frequency and Turnaround Time (TAT)

Serology is forwarded to the National Reference Centre for Parasitology (NRCP) in Montreal. Turnaround time is up to 42 calendar days from receipt at PHO’s laboratory.

Test Methods

Serology is performed at the NRCP by enzyme-linked immunoassay (ELISA) based on antibody capture using antigens from cultured epimastigotes of the Tulahuan and Brazil strains.

Performance and Limitations:
The NRCP reports a sensitivity of 100% in individuals with the indeterminate or chronic forms of Chagas, along with a specificity of 96% overall. Other ELISA tests have reported a sensitivity averaging 90% and specificity averaging 98%.² Serology may be negative in the first 2 to 8 weeks following acute infection. Serology may remain positive for years following treatment in chronic disease and cannot distinguish current from resolved or past infection, but seroreversion may occur within months in acute or congenital cases.³ Cross-reactivity has been observed with Leishmania, Plasmodium (malaria), and syphilis infections.⁴

Algorithm

In cases of diagnostic uncertainty and positive ELISA result, additional testing by immunoblot can be requested to support the diagnosis. If needed, contact PHO’s Laboratory Customer Service at 416-235-6556/1-877-604-4567.

Interpretation

Trypanosoma cruzi ELISA performed at the NRCP:

Optical Density (OD) Sample Value	Result	Interpretation
≥ 0.40	Positive	Detectable antibodies against Trypanosoma cruzi. Does not distinguish current from resolved or past infection. Clinical correlation required.
0.30 to 0.39	Indeterminate	Trypanosoma cruzi antibody status inconclusive. Repeat testing advised if clinically indicated.
< 0.30	Negative	No detectable level of antibodies against Trypanosoma cruzi. False negative results may occur in the first 2 months of symptom onset.

Reporting

Results are received back at PHO’s laboratory, and reports are forwarded to the ordering physician or authorized health care provider (General O. Reg 45/22, s.18) or submitter as indicated on the requisition.

References

Forsyth CJ, Manne-Goehler J, Bern C, Whitman J, Hochberg NS, Edwards M, Marcus R, Beatty NL, Castro-Sesquen YE, Coyle C, Stigler Granados P, Hamer D, Maguire JH, Gilman RH, Meymandi S. Recommendations for Screening and Diagnosis of Chagas Disease in the United States. J Infect Dis. 2022 May 4;225(9):1601-1610. doi: 10.1093/infdis/jiab513.
Afonso AM, Ebell MH, Tarleton RL. A systematic review of high quality diagnostic tests for Chagas disease. PLoS Negl Trop Dis. 2012;6(11):e1881. doi: 10.1371/journal.pntd.0001881. Epub 2012 Nov 8.
Bern C, Montgomery SP, Herwaldt BL, Rassi A Jr, Marin-Neto JA, Dantas RO, Maguire JH, Acquatella H, Morillo C, Kirchhoff LV, Gilman RH, Reyes PA, Salvatella R, Moore AC. Evaluation and treatment of chagas disease in the United States: a systematic review. JAMA. 2007 Nov 14;298(18):2171-81. doi: 10.1001/jama.298.18.2171.
Caballero ZC, Sousa OE, Marques WP, Saez-Alquezar A, Umezawa ES. Evaluation of serological tests to identify Trypanosoma cruzi infection in humans and determine cross-reactivity with Trypanosoma rangeli and Leishmania spp. Clin Vaccine Immunol. 2007 Aug;14(8):1045-9. doi: 10.1128/CVI.00127-07. Epub 2007 May 23.