Avaliação do atendimento laboratorial a sintomáticos respiratórios para tuberculose que procuraram serviços de saúde em Canoas, Rio Grande do Sul, Brasil, 2012 / Evaluation of laboratory care provided to patients with respiratory symptoms of tuberculosis seeking public health services in Canoas, Rio Grande do Sul, Brazil, 2012 / Evaluación del atendimiento laboratorial en sintomáticos respiratorios para tuberculosis que buscaron servicios de salud en Canoas, Rio Grande del Sul, Brasil, 2012

OBJETIVO: descrever o tempo decorrido entre a identificação do sintomático respiratório para tuberculose e a liberação do resultado laboratorial, bem como entre a obtenção do resultado e o início do tratamento. MÉTODOS: estudo descritivo, com dados de casos suspeitos de tuberculose atendidos em serviços públicos de saúde no município de Canoas-RS, Brasil, em 2012. RESULTADOS: foram examinados 1.138 pacientes, com positividade de 7,47%; as medianas de tempo (i) entre identificação do paciente e entrada da amostra de escarro no laboratório e de (ii) processamento do exame foram de 2 (intervalo interquartílico [IIQ] 1-3) e 3 dias (IIQ 1-4), respectivamente, para pacientes com resultado negativo; para pacientes com resultado positivo, esses tempos foram de 2 (IIQ 1-3) e 2,5 dias (IIQ 1-4); entre a liberação do resultado e início do tratamento, transcorreram 3 dias (IIQ 0-5). CONCLUSÃO: os tempos avaliados foram considerados longos em comparação ao preconizado pelo Ministério da Saúde.

OBJECTIVE: to describe the time interval between identification of patients with respiratory symptoms of tuberculosis and laboratory test results release, and between lab results release and commencement of treatment. METHODS: this was a descriptive study with data on patients suspected of having tuberculosis who attended public health services in Canoas-RS, Brazil, in 2012. RESULTS: tests were performed in 1138 patients and positivity rate was 7.47%; medians between (i) patient identification and the sample entering the lab and (ii) processing time were 2 days (Interquartile Range [IQR] 1-3) and 3 days (IQR 1-4), respectively, for people with negative result; for patients who tested positive, these times were 2 days (IQR 1-3) and 2.5 days (IQR 1-4), and the time between release of test results and commencement of treatment was 3 days (IQR 0-5). CONCLUSION: time intervals were considered long when compared to those recommended by the Ministry of Health.

OBJETIVO: describir el tiempo transcurrido entre la identificación de un sintomático respiratorio para tuberculosis y la liberación del resultado laboratorial, y entre la obtención del mismo y el inicio del tratamiento. MÉTODOS: estudio descriptivo que incluyó datos de pacientes con sospecha de tuberculosis que consultaron servicios públicos de salud en el municipio de Canoas-RS, Brasil, en 2012. RESULTADOS: fueron examinados 1138 pacientes, siendo positivos 7,47%; las mediana de tiempo (i) entre la identificación del paciente y entrada de la muestra al laboratorio y (ii) el procesamiento fueron 2 (intervalo interquartílico [IIQ] 1-3) y 3 días (IIQ 1-4), respectivamente, para pacientes con resultado negativo; para pacientes con resultado positivo, los tiempos fueron 2 (IIQ 1-3) y 2.5 (IIQ 1-4) días y el tiempo entre liberación del resultado e inicio del tratamiento fue 3 días (IIQ 0-5). CONCLUSIÓN: los tiempos evaluados fueron considerados largos, comparados con los recomendados por el Ministerio de Salud.

PCR colorimetric dot-blot assay and clinical pretest probability for diagnosis of Pulmonary Tuberculosis in smear-negative patients.

BACKGROUND: Smear-negative pulmonary tuberculosis (SNPTB) accounts for 30% of Pulmonary Tuberculosis (PTB) cases reported annually in developing nations. Polymerase chain reaction (PCR) may provide an alternative for the rapid detection of Mycobacterium tuberculosis (MTB); however little data are available regarding the clinical utility of PCR in SNPTB, in a setting with a high burden of TB/HIV co-infection. METHODS: To evaluate the performance of the PCR dot-blot in parallel with pretest probability (Clinical Suspicion) in patients suspected of having SNPTB, a prospective study of 213 individuals with clinical and radiological suspicion of SNPTB was carried out from May 2003 to May 2004, in a TB/HIV reference hospital. Respiratory specialists estimated the pretest probability of active disease into high, intermediate, low categories. Expectorated sputum was examined by direct microscopy (Ziehl-Neelsen staining), culture (Lowenstein Jensen) and PCR dot-blot. Gold standard was based on culture positivity combined with the clinical definition of PTB. RESULTS: In smear-negative and HIV subjects, active PTB was diagnosed in 28.4% (43/151) and 42.2% (19/45), respectively. In the high, intermediate and low pretest probability categories active PTB was diagnosed in 67.4% (31/46), 24% (6/25), 7.5% (6/80), respectively. PCR had sensitivity of 65% (CI 95%: 50%-78%) and specificity of 83% (CI 95%: 75%-89%). There was no difference in the sensitivity of PCR in relation to HIV status. PCR sensitivity and specificity among non-previously TB treated and those treated in the past were, respectively: 69%, 43%, 85% and 80%. The high pretest probability, when used as a diagnostic test, had sensitivity of 72% (CI 95%:57%-84%) and specificity of 86% (CI 95%:78%-92%). Using the PCR dot-blot in parallel with high pretest probability as a diagnostic test, sensitivity, specificity, positive and negative predictive values were: 90%, 71%, 75%, and 88%, respectively. Among non-previously TB treated and HIV subjects, this approach had sensitivity, specificity, positive and negative predictive values of 91%, 79%, 81%, 90%, and 90%, 65%, 72%, 88%, respectively. CONCLUSION: PCR dot-blot associated with a high clinical suspicion may provide an important contribution to the diagnosis of SNPTB mainly in patients that have not been previously treated attended at a TB/HIV reference hospital.