In acute and congenital Chagas disease, PCR is more sensitive than microscopy, and it is more reliable than antibody-based tests for the diagnosis of congenital disease because it is not affected by transfer of antibodies against T. cruzi from a mother to her baby (passive immunity). PCR is also used to monitor T. cruzi levels in organ transplant recipients and immunosuppressed people, which allows infection or reactivation to be detected at an early stage.In chronic Chagas disease, the concentration of parasites in the blood is too low to be reliably detected by microscopy or PCR, so the diagnosis is usually made using serological tests, which detect immunoglobulin G antibodies against T. cruzi in the blood. Two positive serology results, using different test methods, are required to confirm the diagnosis. If the test results are inconclusive, additional testing methods such as Western blot can be used.Various rapid diagnostic tests for Chagas disease are available. These tests are easily transported and can be performed by people without special training. They are useful for screening large numbers of people and testing people who cannot access healthcare facilities, but their sensitivity is relatively low, and it is recommended that a second method is used to confirm a positive result.T. cruzi parasites can be grown from blood samples by blood culture, xenodiagnosis, or by inoculating animals with the persons blood. In the blood culture method, the persons red blood cells are separated from the plasma and added to a specialized growth medium to encourage multiplication of the parasite.
A chest X-ray can show abnormalities anywhere, but the most specific finding is increased shadow in the periphery of the lungs, away from the heart. Differential diagnosis
This includes:

Asthma
Environmental allergic reaction
Granulomatosis with polyangiitis
Allergic bronchopulmonary aspergillosis
Churg–Strauss syndrome
Loefflers syndrome
Acute eosinophilic pneumonia
Chronic eosinophilic pneumonia (Carringtons disease)
Polyarteritis nodosa
Parasitic infections
Tropical pulmonary eosinophilia
Tuberculosis
Fungal infection
Sarcoidosis
Drug reaction with eosinophilia and systemic symptoms
Mastocytosis
Lymphoproliferative hypereosinophilic syndrome
Myeloproliferative hypereosinophilic syndrome

Treatment
When eosinophilic pneumonia is related to an illness such as cancer or parasitic infection, treatment of the underlying cause is effective in resolving the lung disease. When due to acute or chronic eosinophilic pneumonia, however, treatment with corticosteroids results in a rapid, dramatic resolution of symptoms over the course of one or two days. Either intravenous methylprednisolone or oral prednisone are most commonly used. In acute eosinophilic pneumonia, treatment is usually continued for a month after symptoms disappear and the X-ray returns to normal (usually four weeks total). In chronic eosinophilic pneumonia, treatment is usually continued for three months after symptoms disappear and the X-ray returns to normal (usually four months total). Inhaled steroids such as fluticasone have been used effectively when discontinuation of oral prednisone has resulted in relapse. Because eosinophilic pneumonia affects the lungs, individuals develop difficulty breathing. If enough of the lungs are involved, it may not be possible for a person to breathe without support. Non-invasive machines such as a bilevel positive airway pressure machine may be used. Otherwise, placement of a breathing tube into the mouth may be necessary and a ventilator may be used to help the person breathe.