Socioepidemiological screening of serologically ineligible blood donors due to Chagas disease for the definition of inconclusive cases

Ferreira-Silva, Márcia Maria; Pereira, Gilberto A.; Lages‐Silva, Eliane; Moraes-Souza, Hélio

doi:10.1590/s0074-02762010000600012

Cited by 15 publications

(19 citation statements)

References 17 publications

(24 reference statements)

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“…Many risk factors or predictors were explored and found to be associated with chronic Chagas disease among blood donors [9,12,[17][18][19][20][21][22] and in rural area settings [23][24][25][26][27][28].…”

Section: Discussionmentioning

confidence: 99%

Dealing with initial inconclusive serological results for chronic Chagas disease in clinical practice

Lapa

Saraiva

Hasslocher‐Moreno

et al. 2011

Eur J Clin Microbiol Infect Dis

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Most guidelines for Chagas disease recommend the performance of two serological tests in order to detect it. However, inconclusive results may arise from this strategy. The aim was to describe whether serological follow-up together with the patient's clinical characteristics could clarify the outcome of patients with initial inconclusive test results. In this retrospective case series, all results of Chagas disease serological tests and outpatient visits recorded from 2004 to 2008 were screened for inclusion. The inclusion criterion was clinical suspicion of chronic Chagas disease and the exclusion criteria were previous diagnosis of Chagas disease, suspicion of acute Chagas disease, and serological tests with no corresponding medical evaluation. A total of 1,732 patients were analyzed. Chronic Chagas disease prevalence was 21.1%. After the initial set of serological tests, 2.9% of patients had inconclusive test results. Most of these patients had definite diagnosis after clinical follow-up and the repetition of serological tests in a new blood sample. Loss to follow-up while partaking in the diagnostic investigation reached 17.7%. The prevalence of initial inconclusive serological tests for chronic Chagas disease is low. Clinical evaluations and follow-up clarify the definite diagnosis. Noncompliance to follow-up is a frequent problem. Strategies to reduce inconclusive results and noncompliance are discussed.

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Section: Discussionmentioning

confidence: 99%

Dealing with initial inconclusive serological results for chronic Chagas disease in clinical practice

Lapa

Saraiva

Hasslocher‐Moreno

et al. 2011

Eur J Clin Microbiol Infect Dis

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“…Em estudo desenvolvido no Hemocentro Regional de Uberaba, com 60 doadores inaptos sorológicos (30 repetidamente positivos e 30 com resultados inconclusivos), enquanto 40% dos primeiros apresentaram hemocultura positiva, este método parasitológico de confirmação de infecção chagásica foi 100% negativo nos inconclusivos, evidenciando a baixa ou mesmo ausência de correlação entre reação inconclusiva e doença de Chagas 29 .…”

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O controle da transmissão transfusional

Moraes-Souza

Ferreira-Silva

2011

Rev. Soc. Bras. Med. Trop.

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A alta prevalência de doadores chagásicos nos bancos de sangue do Brasil (6,9%) e da América Latina (6,5%), nas décadas de 60 e 70, aliada ao combate ao vetor a partir dos anos setenta, fez com que a doença de Chagas transfusional, a partir da década de oitenta, se tornasse o principal mecanismo de transmissão da doença na maioria dos países endêmicos. Contudo, os resultados altamente favoráveis do combate ao vetor e da cobertura sorológica dos doadores, reduziu a prevalência de soropositividade para 0,2% e 1,3%, respectivamente, no Brasil e América Latina e o índice de transmissão anual, via transfusão de sangue no Brasil, de 20.000 para 13 em quatro décadas. Entretanto, paralelamente aos grandes avanços obtidos pelos países endêmicos, a doença de Chagas alcançou, via processo migratório, os países não endêmicos da América do Norte e da Europa, além do Japão e Austrália, colocando em risco os receptores de sangue destes países e transformando a doença de Chagas num problema de saúde global. A segurança transfusional, propiciada pela triagem sorológica, trouxe, porém outro importante problema, qual seja, a alta proporção de reações inconclusivas e dois grandes desafios: o significado de tais exames e que orientação proporcionar ao doador. Contudo, as estratégias adotadas pelos países não endêmicos e os avanços alcançados pelos endêmicos, prenunciam o breve, auspicioso e intensamente sonhado controle vetorial e transfusional da doença de Chagas. Palavras-chaves: Transfusão de sangue. Doença de Chagas. Transmissão transfusional. Medidas de controle. ABSTRACTThe high prevalence of chagasic blood donors in blood centers in Brazil (6.9%) and in Latin America (6.5%) in the 60's and 70's, together with the combat to the vector since the 70's have made transfusion Chagas disease the main mechanism of the disease transmission in the 80's. However, the highly favorable results achieved to eliminate the vector and the serologic screening of blood donors, reduced the prevalence of serum positivity to 0.2% and 1.3%, respectively and the rate of annual transmission through blood transfusion from 20.000 to 13 in four decades in Brazil. Nevertheless, despite outstanding advancements in endemic countries, Chagas disease reached, via migration, non-endemic countries in North America and Europe besides Japan and Australia, placing their blood recipients at risk and turning Chagas disease into a worldwide health problem. Transfusion safety through serologic selection raised another big issue i.e. high proportion of inconclusive reactions as well as two great challenges: the meaning of such exams and what guidelines to provide the donor. However, the strategies adopted by non-endemic countries and the advancements achieved by endemics so far forecast the highly wished vector and transfusion control of Chagas disease. O processo migratório no sentido campo-cidade, com o início da industrialização do Brasil, a partir da década de cinquenta, promoveu a urbanização da doença e foi responsável pela alta prevalência de doadores chagásicos...

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“…(8,11,20,28,29) Many studies report that inconclusive samples repeatedlyshowed negative results on using other tests. (11,26) …”

Section: Discussionmentioning

confidence: 99%

“…Studies report that the combination of epidemiological data with results of high performance testing allows a more accurate view of the serologic status of donors (10,11) . To confirm these data, we find estimates for the sensitivity and specificity close to 100% for certain epidemiological covariates suggesting that it is important to consider the inclusion of covariates in the structure of the model to evaluate the performance of the diagnostic tests.…”

Section: Discussionmentioning

confidence: 99%

Performance of six diagnostic tests to screen for Chagas disease in blood banks and prevalence of Trypanosoma cruzi infection among donors with inconclusive serology screening based on the analysis of epidemiological variables

Pereira

Louzada

Barbosa

et al. 2012

Revista Brasileira De Hematologia E Hemoterapia

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Objective The frequent occurrence of inconclusive serology in blood banks and the absence of a gold standard test for Chagas'disease led us to examine the efficacy of the blood culture test and five commercial tests (ELISA, IIF, HAI, c-ELISA, rec-ELISA) used in screening blood donors for Chagas disease, as well as to investigate the prevalence of Trypanosoma cruzi infection among donors with inconclusive serology screening in respect to some epidemiological variables. Methods To obtain estimates of interest we considered a Bayesian latent class model with inclusion of covariates from the logit link. Results A better performance was observed with some categories of epidemiological variables. In addition, all pairs of tests (excluding the blood culture test) presented as good alternatives for both screening (sensitivity > 99.96% in parallel testing) and for confirmation (specificity > 99.93% in serial testing) of Chagas disease. The prevalence of 13.30% observed in the stratum of donors with inconclusive serology, means that probably most of these are non-reactive serology. In addition, depending on the level of specific epidemiological variables, the absence of infection can be predicted with a probability of 100% in this group from the pairs of tests using parallel testing. Conclusion The epidemiological variables can lead to improved test results and thus assist in the clarification of inconclusive serology screening results. Moreover, all combinations of pairs using the five commercial tests are good alternatives to confirm results.

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Socioepidemiological screening of serologically ineligible blood donors due to Chagas disease for the definition of inconclusive cases

Cited by 15 publications

References 17 publications

Dealing with initial inconclusive serological results for chronic Chagas disease in clinical practice

Dealing with initial inconclusive serological results for chronic Chagas disease in clinical practice

O controle da transmissão transfusional

Performance of six diagnostic tests to screen for Chagas disease in blood banks and prevalence of Trypanosoma cruzi infection among donors with inconclusive serology screening based on the analysis of epidemiological variables

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