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PubMed This is a summary of 17 peer-reviewed journal articles Updated
Cardiology · Chagas disease

Getting the Right Tests: Diagnosis and Monitoring

At a Glance

Chronic Chagas disease is confirmed with two different antibody tests, then heart health is mapped with an EKG and, when appropriate, an echocardiogram, cardiac MRI, or Holter monitor. Repeated testing can detect heart changes before symptoms appear.

Diagnosing Chagas disease is not as simple as a single “yes or no” blood test. Because the parasite levels in your blood are very low during the chronic phase, doctors must look for the antibodies your body has built against it [1].

Getting a clear diagnosis and a baseline of your heart’s health is the most important step in protecting your future. This process requires a specific “two-test” rule and a series of detailed heart scans.

The Two-Test Requirement

To confirm you have a chronic Chagas infection, medical guidelines require two different serological (antibody) tests to be positive [2][3]. (Note: Acute, congenital, or reactivated infections may use direct DNA tests like PCR instead).

  • Why two?: No single test is perfect. Some tests may give a “false positive” if you have had other infections, like Leishmaniasis [4].
  • The logic: Doctors use two tests that use different methods or different parts of the parasite to ensure the results are accurate. If the two tests disagree (one is positive and one is negative), a third “tiebreaker” test is usually performed at a specialized reference laboratory [5].

Your Baseline Heart “Map”

Once the infection is confirmed, your care team needs to determine if the parasite has begun to affect your heart. Even if you feel 100% healthy, you should receive these baseline clinical evaluations.

1. 12-Lead EKG (Electrocardiogram)

The EKG is the most important “gatekeeper” test and a universal baseline. It records the electrical signals in your heart. In Chagas, the EKG often shows the very first signs of trouble, such as a Right Bundle Branch Block (RBBB)—a delay in the electrical signal to the right side of the heart [6][7].

2. Echocardiogram (Heart Ultrasound)

While the EKG checks the “wiring,” the echocardiogram checks the “pump.” Depending on your symptoms and EKG findings, this ultrasound allows doctors to:

  • Measure your ejection fraction (how much blood your heart pumps out with each beat) [8].
  • Look for an apical aneurysm (a thinning or ballooning at the tip of the heart) [9].
  • Check for thrombi (blood clots) that can form in weak areas of the heart [10].

3. Cardiac MRI (The “Deep Dive”)

A cardiac MRI with late gadolinium enhancement (LGE) is a sensitive way to characterize tissue. It can detect myocardial fibrosis (scar tissue) that is invisible on an EKG or ultrasound [11][12]. Research shows that even some patients in the “silent” phase already have small areas of scarring [13]. Knowing how much scar tissue is present helps doctors predict your risk for future rhythm problems, although it is not routinely required for every asymptomatic patient [14].

4. Holter Monitor

If you have ever felt your heart skip a beat or feel dizzy, your doctor may ask you to wear a Holter monitor—a portable EKG that records your heart rhythm for 24 to 48 hours. This catches intermittent “silent” arrhythmias that a standard 10-second EKG might miss [15][16].

Why “Serial” Monitoring Matters

Chagas is a progressive disease, but it moves very slowly—often over 20 to 30 years. About 1.9% of people in the “silent” phase will develop heart changes each year [17].

Because structural damage often happens before you feel any symptoms, you need serial surveillance [8]. This means having these tests repeated on an individualized schedule—for example, once a year for an EKG and every few years for an echocardiogram—even if you feel fine. This “proactive” approach allows your doctor to start heart-protective medications the moment a change is detected, rather than waiting for a crisis.

Test What it Finds Why it Matters
EKG Electrical delays (RBBB) Often the first sign of Chagas
Echocardiogram Weak pumping, aneurysms Helps stage the disease
Cardiac MRI Early scar tissue (fibrosis) Selectively helps predict future risk
Holter Monitor Hidden irregular heartbeats Guides treatment to prevent sudden events

By staying on top of these tests, you are not just waiting for the disease to act; you are actively monitoring your health to stay ahead of it.

Common questions in this guide

Why do I need two blood tests to confirm chronic Chagas disease?
Chronic Chagas disease is usually confirmed with two different antibody tests because no single test is perfect. Using different methods or parasite targets helps reduce the chance of a false-positive result. If the results conflict, a specialized laboratory may perform a third test.
What heart tests are recommended after a Chagas diagnosis?
A 12-lead electrocardiogram, or EKG, is the key baseline test for checking the heart’s electrical signals. Depending on your symptoms and EKG findings, your clinician may add an echocardiogram, cardiac MRI, or Holter monitor to assess pumping strength, scar tissue, or intermittent rhythm problems.
What does a right bundle branch block mean in Chagas disease?
A right bundle branch block is a delay in the electrical signal traveling through the right side of the heart. In Chagas disease, it can be one of the early changes seen on an EKG, but your clinician must interpret it alongside your other results.
What can an echocardiogram detect in Chagas cardiomyopathy?
An echocardiogram shows how well the heart pumps by measuring ejection fraction, or the amount of blood pumped with each beat. It can also look for an apical aneurysm and blood clots, which may form in weakened areas of the heart.
Should I have a cardiac MRI if I have no symptoms?
A cardiac MRI with late gadolinium enhancement can find heart muscle scarring that an EKG or echocardiogram may not show. Some people without symptoms have small areas of scarring, but MRI is not routinely needed for every person without symptoms. Your clinician can decide whether it would add useful information based on your other tests and risk.
How often should Chagas heart monitoring be repeated?
Follow-up timing is individualized because Chagas disease can progress slowly and heart damage may develop before symptoms. A clinician may suggest an EKG about once a year and an echocardiogram every few years, but your schedule should reflect your symptoms, EKG, and other findings.
When is a Holter monitor useful for Chagas disease?
A Holter monitor records your heart rhythm continuously for 24 to 48 hours and can detect intermittent irregular beats that a brief EKG may miss. It may be useful if you have palpitations, dizziness, or other concerns about an abnormal rhythm.

Questions to Ask Your Doctor

Curated prompts to bring to your next appointment.

  1. 1.Can you confirm that my diagnosis was based on two different types of blood tests? Which specific assays were used?
  2. 2.Does my current EKG show any signs of conduction delay, like a right bundle branch block (RBBB)?
  3. 3.Was an apical aneurysm or any evidence of blood clots seen on my echocardiogram?
  4. 4.Given that I am currently asymptomatic, how often do you recommend I return for follow-up testing?
  5. 5.Would a cardiac MRI provide more information about my risk of future heart problems, even if my other tests are normal?
  6. 6.Do I need a 24-hour Holter monitor to check for silent rhythm issues?

Questions For You

Tap a prompt to share your answer — we'll use it plus this page's context to start a tailored conversation.

References

References (17)
  1. 1

    Evaluation of Chagas TESA VirClia assay for chronic Trypanosoma cruzi infection diagnosis and post-treatment follow-up.

    Silgado A, Mediavilla A, Martínez-Vallejo P, et al.

    Journal of clinical microbiology 2026; (64(7)):e0173925 doi:10.1128/jcm.01739-25.

    PMID: 42284051
  2. 2

    Western blot using Trypanosoma cruzi chimeric recombinant proteins for the serodiagnosis of chronic Chagas disease: A proof-of-concept study.

    Daltro RT, Santos EF, Silva ÂAO, et al.

    PLoS neglected tropical diseases 2022; (16(11)):e0010944 doi:10.1371/journal.pntd.0010944.

    PMID: 36441769
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    Recommendations for Screening and Diagnosis of Chagas Disease in the United States.

    Forsyth CJ, Manne-Goehler J, Bern C, et al.

    The Journal of infectious diseases 2022; (225(9)):1601-1610 doi:10.1093/infdis/jiab513.

    PMID: 34623435
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    Chronic Chagas Disease Diagnosis: A Comparative Performance of Commercial Enzyme Immunoassay Tests.

    Santos FL, de Souza WV, Barros Mda S, et al.

    The American journal of tropical medicine and hygiene 2016; (94(5)):1034-9 doi:10.4269/ajtmh.15-0820.

    PMID: 26976886
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    Evaluation of the Performance of Ortho T. cruzi ELISA Test System for the Detection of Antibodies to Trypanosoma cruzi.

    Rivera HN, McAuliffe I, Aderohunmu T, et al.

    Journal of clinical microbiology 2022; (60(8)):e0013422 doi:10.1128/jcm.00134-22.

    PMID: 35862752
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    Chagas Cardiomyopathy: Usefulness of EKG and Echocardiogram in a Non-Endemic Country.

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    PloS one 2016; (11(6)):e0157597 doi:10.1371/journal.pone.0157597.

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    Electrocardiographic abnormalities in chagasic patients compared to the general population: A systematic review with updated meta-analysis.

    de Oliveira BFS, de Santana CVC, Pereira LFV, et al.

    Journal of electrocardiology 2025; (90()):153893 doi:10.1016/j.jelectrocard.2025.153893.

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    Multimodality imaging evaluation of Chagas disease: an expert consensus of Brazilian Cardiovascular Imaging Department (DIC) and the European Association of Cardiovascular Imaging (EACVI).

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    Pathology of Chronic Chagas Cardiomyopathy in the United States:  A Detailed Review of 13 Cardiectomy Cases.

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    Stroke in Chagas disease: from pathophysiology to clinical practice.

    Lage TAR, Tupinambás JT, Pádua LB, et al.

    Revista da Sociedade Brasileira de Medicina Tropical 2022; (55()):e0575 doi:10.1590/0037-8682-0575-2021.

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    Myocardial tissue characterization in Chagas' heart disease by cardiovascular magnetic resonance.

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    PMID: 26581396
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    Cardiac Fibrosis and Changes in Left Ventricle Function in Patients with Chronic Chagas Heart Disease.

    Santos JBF, Gottlieb I, Tassi EM, et al.

    Arquivos brasileiros de cardiologia 2021; (117(6)):1081-1090 doi:10.36660/abc.20200597.

    PMID: 34644785
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    The Presence and Extension of Myocardial Fibrosis in the Undetermined Form of Chagas' Disease: A Study Using Magnetic Resonance.

    Noya-Rabelo MM, Macedo CT, Larocca T, et al.

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    PMID: 29466491
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    Long-Term Prognostic Value of Myocardial Fibrosis in Patients With Chagas Cardiomyopathy.

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    PMID: 30466515
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    Autonomic denervation, myocardial hypoperfusion and fibrosis may predict ventricular arrhythmia in the early stages of Chagas cardiomyopathy.

    de Brito ASX, Moll-Bernardes RJ, Pinheiro MVT, et al.

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    Associations between Cardiac Magnetic Resonance T1 Mapping Parameters and Ventricular Arrhythmia in Patients with Chagas Disease.

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    Risk of Chronic Cardiomyopathy Among Patients With the Acute Phase or Indeterminate Form of Chagas Disease: A Systematic Review and Meta-analysis.

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This page is for informational purposes only and does not constitute medical advice. Your clinician should interpret your Chagas tests and set a heart-monitoring schedule for your specific situation.

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