Aspectos da padronização de testes sorológicos para a doença de Chagas: um teste imunoenzimático para a triagem de doadores de sangue

Ferreira, Antônio Walter; Belem, Z R; Moura, M E G; Camargo, M. E.

doi:10.1590/s0036-46651991000200006

Cited by 21 publications

(7 citation statements)

References 2 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…Because it presents high sensitivity and specificity, it is also indicated as the only serological method for seroepidemiological enquiries that can determine the prevalence of the infection [5,[31][32][33]. However, in clinical settings, the result of only 1 serological test is insufficient to diagnose the condition of the chronic T. cruzi carrier [5][6][7][8].…”

Section: Discussionmentioning

confidence: 99%

Definition of a diagnostic routine in individuals with inconclusive serology for chagas disease

Picka¹,

Meira²,

Carvalho³

et al. 2007

Braz J Infect Dis

View full text Add to dashboard Cite

Despite the existence of highly sensitive tests, inconclusive serological results are frequent in chronic chagasic infection. This study aimed to define a diagnostic conduct for 30 individuals with inconclusive serology (G3) for chagasic infection assisted at the Outpatient Unit for Infectious and Parasitic Diseases of the Botucatu School of Medicine. Twenty-one individuals with negative serology (G1) and 33 with positive serology (G2) were also studied. Serological methods ELISA, HAI, IFI and immunoblotting TESA-cruzi were used for G1, G2 and G3, and parasitological methods xenodiagnosis, hemoculture and PCR-LIT were used for G2 and G3 individuals. ELISA, HAI and IFI were performed in 5 different blood samples in G2 and G3. TESA-cruzi was carried out only once in G1, G2 and G3 and, since it is the most sensitive, it was utilized as standard. In G3, positivity for ELISA reached 86% in the fifth blood sample; the ELISA+HAI+IFI combination showed a maximum of 44.8% in the second sample; and TESA-cruzi, 76% in one single sample. Xenodiagnosis positivity was 9.4%; hemoculture showed 15.2%; and PCR-LIT exhibited 22% positivity in G2. Nevertheless, in G3, positivity percentage was 3.4% for xenodiagnosis, 6.7% for PCR-LIT, and no positive result was found for hemoculture. In G3, PCR-LIT resolved one case which was still inconclusive according to serology tests. In order to define inconclusive diagnoses, the results suggest the combined use of ELISA+HAI+IFI in 2 blood samples, decreasing the occurrence of false positive/negative results. If results remain inconclusive, the performance of TESA-cruzi and PCR-LIT, if necessary, is recommended.

show abstract

Section: Discussionmentioning

confidence: 99%

Definition of a diagnostic routine in individuals with inconclusive serology for chagas disease

Picka¹,

Meira²,

Carvalho³

et al. 2007

Braz J Infect Dis

View full text Add to dashboard Cite

show abstract

“…Additionally, the results obtained are precise since readings are objective, and test validation criteria and interpretation of results are rigorous. The majority of the commercially available ELISAs employ antigens obtained by lysis of epimastogote or trypomastigote forms of T. cruzi (3,9). These tests are sensitive but often fail to distinguish between T. cruzi-specific and Leishmania sp.-specific antibodies, thus leading frequently to false-positive results (2).…”

mentioning

confidence: 99%

Enzyme-Linked Immunosorbent Assay for Serological Diagnosis of Chagas' Disease Employing a Trypanosoma cruzi Recombinant Antigen That Consists of Four Different Peptides

et al. 2001

View full text Add to dashboard Cite

Serological tests to detect Trypanosoma cruzi antibodies have been used for screening blood donors, for epidemic studies, and for diagnosis of probably infected persons. Among different tests, the enzyme-linked immunosorbent assay (ELISA) with total, semipurified, or synthetic antigens has been widely used, mainly due to its easy automation. Aiming to improve serological studies concerning Chagas' disease, we have developed and evaluated a new test, the TcF-ELISA, using an artificially engineered recombinant antigen, which contains tandem sequences of different T. cruzi-specific peptides. The sensibility of the TcF-ELISA was determined with 101 serum samples from chagasic patients well-defined by clinical and epidemiological criteria. The specificity was determined with 39 serum samples from leishmaniasis or kala-azar patients and 150 serum samples from nonchagasic blood donors from Sao Paulo, Brazil. The TcF-ELISA showed 100% sensitivity and 98.94% of specificity. Compared with conventional ELISA (with semipurified T. cruzi epimastigote antigens), the TcF-ELISA showed advantages; for example, it distinguishes better between reagent and nonreagent serum and provides better precision and a lower occurrence of leishmaniasis cross-reactions. Our studies demonstrate high reproducibility between two different lots of the TcF ELISA and its applicability for the serological diagnosis of Chagas' disease.

show abstract

“…4). This higher diagnostic resolution of the IIF-A in relation to IIF-E, as well as to other serologic tests with epimastigote antigens (12,16), is significant. This type of serologic profile which gives high diagnostic resolution is usually seen when monoclonal or recombinant antigens are used in the tests.…”

Section: Discussionmentioning

confidence: 77%

High resolution of Trypanosoma cruzi amastigote antigen in serodiagnosis of different clinical forms of Chagas' disease

et al. 1993

View full text Add to dashboard Cite

The serodiagnosis of Chagas' disease, a highly prevalent disorder in South American countries, is usually made by the detection of antibodies to Trypanosoma cruzi epimastigote antigen. In this study, we assess the diagnostic performance of the immunofluorescence test with T. cruzi (Y strain) amastigote antigen from an LLC-MK2-infected cell supernatant in comparison with a test with the conventional epimastigote antigen. A total of 238 serum samples from patients in the acute and chronic phases of the disease, with the chronic indeterminate, cardiac, and digestive forms, and from nonchagasic individuals were tested for the presence of immunoglobulin G (IgG), IgM, and IgA antibodies. The reactivity of the amastigote antigen in terms of geometric mean titers was 2 to 4 times higher than that of the epimastigote antigen. Clear-cut results were obtained with the amastigote antigen, with no overlapping of true and false positives. IgG antibodies to amastigotes were found in all patients with Chagas' disease, whereas all sera from nonchagasic patients were negative, except for those from patients with visceral leishmaniasis, in which 63% cross-reactivity was observed. IgM antibodies to amastigotes were detected in 100% of sera from patients with acute Chagas' disease and in 7.5% of sera from patients with chronic Chagas' disease, whereas IgA antibodies were found in 60% of sera from patients in the acute phase and in 33% of sera from patients in the chronic phase. Despite the cross-reactivity observed with sera from visceral leishmaniasis patients, the IgG immunofluorescence test with the amastigote antigen had the highest sensitivity, specificity, and efficiency. No relationship was observed between the class-specific antibodies or their titers and the clinical forms of patients in the chronic phase. Amastigotes from the cell culture supernatant proved to be useful as an alternative antigen to epimastigotes because of their high resolution in the serodiagnosis of Chagas' disease.

show abstract

Aspectos da padronização de testes sorológicos para a doença de Chagas: um teste imunoenzimático para a triagem de doadores de sangue

Cited by 21 publications

References 2 publications

Definition of a diagnostic routine in individuals with inconclusive serology for chagas disease

Definition of a diagnostic routine in individuals with inconclusive serology for chagas disease

Enzyme-Linked Immunosorbent Assay for Serological Diagnosis of Chagas' Disease Employing a Trypanosoma cruzi Recombinant Antigen That Consists of Four Different Peptides

High resolution of Trypanosoma cruzi amastigote antigen in serodiagnosis of different clinical forms of Chagas' disease

Contact Info

Product

Resources

About