PCR colorimetric dot-blot assay and clinical pretest probability for diagnosis of Pulmonary Tuberculosis in Smear-Negative patients

Scherer, Luciene Cardoso; Sperhacke, Rosa Dea; Jarczewski, Carla Adriane; Cafrune, Patrícia Izquierdo; Minghelli, Simone; Ribeiro, Marta Osório; Mello, Fernanda Cq; Ruffino-Netto, Antônio; Rossetti, Maria L.R.; Kritski, Afrânio Lineu

doi:10.1186/1471-2458-7-356

Cited by 8 publications

(8 citation statements)

References 23 publications

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“…The median time to reveal the growth of MTB was 30 days (Interquartile Range [IQR] 30 to 45) for smear and culture, and the median time for detection of MTB by Detect-TB was 3.32 days (IQR 3.0 to 3.75) (p < 0.01). This value was used as the standard at which release from isolation could be permitted [ 29 ].…”

Section: Resultsmentioning

confidence: 99%

Smear plus Detect-TB for a sensitive diagnosis of pulmonary tuberculosis: a cost-effectiveness analysis in an incarcerated population

et al. 2014

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BackgroundPrison conditions can favor the spread of tuberculosis (TB). This study aimed to evaluate in a Brazilian prison: the performance and accuracy of smear, culture and Detect-TB; performance of smear plus culture and smear plus Detect-TB, according to different TB prevalence rates; and the cost-effectiveness of these procedures for pulmonary tuberculosis (PTB) diagnosis.MethodsThis paper describes a cost-effectiveness study. A decision analytic model was developed to estimate the costs and cost-effectiveness of five routine diagnostic procedures for diagnosis of PTB using sputum specimens: a) Smear alone, b) Culture alone, c) Detect-TB alone, d) Smear plus culture and e) Smear plus Detect-TB. The cost-effectiveness ratio of costs were evaluated per correctly diagnosed TB case and all procedures costs were attributed based on the procedure costs adopted by the Brazilian Public Health System.ResultsA total of 294 spontaneous sputum specimens from patients suspected of having TB were analyzed. The sensibility and specificity were calculated to be 47% and 100% for smear; 93% and 100%, for culture; 74% and 95%, for Detect-TB; 96% and 100%, for smear plus culture; and 86% and 95%, for smear plus Detect-TB. The negative and positive predictive values for smear plus Detect-TB, according to different TB prevalence rates, ranged from 83 to 99% and 48 to 96%, respectively. In a cost-effectiveness analysis, smear was both less costly and less effective than the other strategies. Culture and smear plus culture were more effective but more costly than the other strategies. Smear plus Detect-TB was the most cost-effective method.ConclusionsThe Detect-TB evinced to be sensitive and effective for the PTB diagnosis when applied with smear microscopy. Diagnostic methods should be improved to increase TB case detection. To support rational decisions about the implementation of such techniques, cost-effectiveness studies are essential, including in prisons, which are known for health care assessment problems.Electronic supplementary materialThe online version of this article (doi:10.1186/s12879-014-0678-x) contains supplementary material, which is available to authorized users.

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Section: Resultsmentioning

confidence: 99%

Smear plus Detect-TB for a sensitive diagnosis of pulmonary tuberculosis: a cost-effectiveness analysis in an incarcerated population

et al. 2014

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“…The time to detect M. tuberculosis in the culture was 30 days in this study. This cohort is the same as previous published by our group [ 20 ]. The median time to reveal growth of MTB was 30 days (interquartile range [IQR] 30 to 45) for smear/culture and the median time for detection of MTB by PCR was 3.32 days (IQR 3.0 to 3.75), respectively (p < 0.01).…”

Section: Methodsmentioning

confidence: 96%

“…The median time to reveal growth of MTB was 30 days (interquartile range [IQR] 30 to 45) for smear/culture and the median time for detection of MTB by PCR was 3.32 days (IQR 3.0 to 3.75), respectively (p < 0.01). This value was used as the standard at which release from isolation could be permitted [ 20 ]…”

Section: Methodsmentioning

confidence: 99%

Cost-effectiveness analysis of PCR for the rapid diagnosis of pulmonary tuberculosis

et al. 2009

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BackgroundTuberculosis is one of the most prominent health problems in the world, causing 1.75 million deaths each year. Rapid clinical diagnosis is important in patients who have co-morbidities such as Human Immunodeficiency Virus (HIV) infection. Direct microscopy has low sensitivity and culture takes 3 to 6 weeks [1-3]. Therefore, new tools for TB diagnosis are necessary, especially in health settings with a high prevalence of HIV/TB co-infection.MethodsIn a public reference TB/HIV hospital in Brazil, we compared the cost-effectiveness of diagnostic strategies for diagnosis of pulmonary TB: Acid fast bacilli smear microscopy by Ziehl-Neelsen staining (AFB smear) plus culture and AFB smear plus colorimetric test (PCR dot-blot).From May 2003 to May 2004, sputum was collected consecutively from PTB suspects attending the Parthenon Reference Hospital. Sputum samples were examined by AFB smear, culture, and PCR dot-blot. The gold standard was a positive culture combined with the definition of clinical PTB. Cost analysis included health services and patient costs.ResultsThe AFB smear plus PCR dot-blot require the lowest laboratory investment for equipment (US$ 20,000). The total screening costs are 3.8 times for AFB smear plus culture versus for AFB smear plus PCR dot blot costs (US$ 5,635,760 versus US$ 1,498, 660). Costs per correctly diagnosed case were US$ 50,773 and US$ 13,749 for AFB smear plus culture and AFB smear plus PCR dot-blot, respectively. AFB smear plus PCR dot-blot was more cost-effective than AFB smear plus culture, when the cost of treating all correctly diagnosed cases was considered. The cost of returning patients, which are not treated due to a negative result, to the health service, was higher in AFB smear plus culture than for AFB smear plus PCR dot-blot, US$ 374,778,045 and US$ 110,849,055, respectively.ConclusionAFB smear associated with PCR dot-blot associated has the potential to be a cost-effective tool in the fight against PTB for patients attended in the TB/HIV reference hospital.

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“…(24,25) In contrast, the use of nPCR in blood samples is important in the attempt to elucidate cases of the disease in the pulmonary or paucibacillary forms, in which the sputum smear microscopy is negative or when there is no expectoration.…”

Section: Discussionmentioning

confidence: 99%

Desempenho da técnica nested PCR na detecção específica do complexo Mycobacterium tuberculosis em amostras sanguíneas de pacientes pediátricos

Lima

Montenegro

et al. 2009

J. bras. pneumol.

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Objective: To evaluate the performance of nested PCR (nPCR) in detecting the Mycobacterium tuberculosis complex in blood samples of patients suspected of having TB, in order to determine its potential for use as an auxiliary tool in the laboratory diagnosis of TB in children. Methods: Detection of the M. tuberculosis complex in blood samples using as a target the insertion sequence IS6110 of the genomic DNA of the bacillus. Blood samples of 120 patients were evaluated. All of the patients were under 15 years of age at the time of their treatment at public hospitals in the city of Recife, Brazil (between January of 2003 and August of 2005). Attending physicians at the hospitals diagnosed TB based on the criteria recommended by the American Thoracic Society. The nPCR amplified a 123-bp fragment with outer oligonucleotides (IS1/IS2) and, in the subsequent reaction, using inner oligonucleotides (IS3/IS4), generating an 81-bp amplicon. Results: Active or latent TB was found in 65 patients, TB was ruled out in 28 suspected cases, and 27 patients were TB-free (controls). The sensitivity of nPCR was 26.15% and was significantly higher for the extrapulmonary form of the disease (55.56%) than for the pulmonary form (18.18%). The specificity was 92.73%. Conclusions: Despite the difficulties in diagnosing TB in children and the low number of cases evaluated in the present study, nPCR in blood samples proved to be a rapid and specific technique, albeit one with low sensitivity. In order to establish its true usefulness in the diagnosis of paucibacillary forms, especially extrapulmonary TB, further studies need to be carried out with a larger sample of children and analyzing biological specimens other than blood.Keywords: Tuberculosis; Diagnosis; Blood; Polymerase chain reaction. ResumoObjetivo: Avaliar o desempenho da técnica nested PCR (nPCR) para detectar o complexo Mycobacterium tuberculosis em amostras de sangue de pacientes com suspeita de TB para sua possível utilização como uma ferramenta auxiliar no diagnóstico laboratorial da doença em crianças. Métodos: Detecção do complexo M. tuberculosis em amostras de sangue usando como alvo a sequência de inserção IS6110 do DNA genômico do bacilo. Foram avaliados 120 pacientes, menores de 15 anos de idade, de ambos os sexos, provenientes de hospitais públicos do Recife (PE), no período entre janeiro de 2003 e agosto de 2005. O diagnóstico de TB foi realizado pelo médico assistente do serviço de saúde de acordo com os critérios da Sociedade Torácica Americana. A nPCR amplificou um fragmento de 123 pb com oligonucleotídeos externos (IS1/IS2) e, na reação subsequente, com oligonucleotídeos internos (IS3/IS4), gerando um amplicon de 81 pb. Resultados: A TB ativa ou latente esteve presente em 65 pacientes, foi descartada em 28 suspeitos e 27 não tinham a doença (controles). A sensibilidade da nPCR foi de 26,15%, sendo significativamente maior na forma extrapulmonar (55,56%) em relação à pulmonar (18,18%), e a especificidade foi de 92,73%. Conclusões: Diante das dificuldades ...

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PCR colorimetric dot-blot assay and clinical pretest probability for diagnosis of Pulmonary Tuberculosis in Smear-Negative patients

Cited by 8 publications

References 23 publications

Smear plus Detect-TB for a sensitive diagnosis of pulmonary tuberculosis: a cost-effectiveness analysis in an incarcerated population

Smear plus Detect-TB for a sensitive diagnosis of pulmonary tuberculosis: a cost-effectiveness analysis in an incarcerated population

Cost-effectiveness analysis of PCR for the rapid diagnosis of pulmonary tuberculosis

Desempenho da técnica nested PCR na detecção específica do complexo Mycobacterium tuberculosis em amostras sanguíneas de pacientes pediátricos

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