RESUMO
SETTING: Ten peripheral laboratories performing routine acid-fast bacilli (AFB) smear microscopy in Lima, Peru. OBJECTIVES: To test whether external quality assessment (EQA) rechecking of AFB smears becomes more efficient with stratified lot sampling of treatment follow-up smears. DESIGN: In 2 consecutive years, a stratified lot sample of 36 treatment follow-up slides and 24 diagnostic slides were randomly selected and blindly rechecked. A second controller determined the final result for discordant slides. Feedback was provided to laboratory technicians during supervisory visits. RESULTS: More false-negative errors were found in the follow-up slides than in the tuberculosis suspect slides: 25 vs. 3. This represented a yield of 3.5% in 720 follow-up slides and only 0.6% in 480 diagnostic slides. Positive predictive values were high in both years. Respectively three and eight laboratories did not reach a relative sensitivity of >65% during the first and second year, and a clear improvement was seen in only one laboratory. Excessive workload seemed to preclude raising the level of routine performance. CONCLUSIONS: EQA with stratified lot sampling of treatment follow-up slides proved very efficient and effective for identifying laboratories with substandard performance in a setting with low positivity rates in routine diagnostic smears.
Assuntos
Técnicas de Laboratório Clínico/normas , Microscopia/normas , Mycobacterium tuberculosis/isolamento & purificação , Indicadores de Qualidade em Assistência à Saúde , Tuberculose/diagnóstico , Antituberculosos/uso terapêutico , Reações Falso-Negativas , Reações Falso-Positivas , Humanos , Variações Dependentes do Observador , Peru , Guias de Prática Clínica como Assunto , Valor Preditivo dos Testes , Reprodutibilidade dos Testes , Resultado do Tratamento , Tuberculose/tratamento farmacológico , Tuberculose/microbiologia , Carga de TrabalhoRESUMO
OBJECTIVE: To determine the efficiency of routine tuberculosis (TB) case detection by examining sputum smear positivity for acid-fast bacilli in relation to duration of cough, characteristics of TB suspects examined and health service factors. METHOD: We combined patient interviews with routine data from laboratory registers in 6 health care facilities in San Juan de Lurigancho district, Lima, Peru. A TB case was defined as a TB suspect with at least one positive sputum smear. We calculated adjusted odds ratios with 95% confidence intervals for the association between smear positivity and health service and patient's characteristics. RESULTS: Smear positivity was 7.3% (321/4376). Of the 4376 adults submitting sputa, 55.3% (2418) reported cough for <14 days. In this group, smear microscopy yielded 3.2% (78/2418) positive results vs. 12.4% (243/1958) in patients coughing for 14 or more days. Having cough for >2 weeks, being referred by health care staff, attending a secondary-level health care facility, male sex and age between 15 and 44 years were independent determinants of smear positivity. CONCLUSIONS: Routine case detection yields a low proportion of smear-positive cases because of the inclusion of a high proportion of patients without cough or coughing for <2 weeks. Adherence to the national TB control programme guidelines on the selection of TB suspects would have a positive impact on the smear positivity rate, reduce laboratory costs and workload and possibly improve the reading quality of smear microscopy.
Assuntos
Tosse/microbiologia , Mycobacterium tuberculosis/isolamento & purificação , Escarro/microbiologia , Tuberculose Pulmonar/diagnóstico , Adolescente , Adulto , Distribuição por Idade , Feminino , Humanos , Masculino , Programas de Rastreamento/métodos , Pessoa de Meia-Idade , Peru/epidemiologia , Distribuição por Sexo , Fatores de Tempo , Tuberculose Pulmonar/complicações , Tuberculose Pulmonar/epidemiologia , Adulto JovemRESUMO
OBJECTIVES: To assess the effectiveness of clinical audit in improving the quality of diagnostic care provided to patients suspected of tuberculosis; and to understand the contextual factors which impede or facilitate its success. METHODS: Twenty-six health centres in Cuba, Peru and Bolivia were recruited. Clinical audit was introduced to improve the diagnostic care for patients attending with suspected TB. Standards were based on the WHO and TB programme guidelines relating to the appropriate use of microscopy, culture and radiological investigations. At least two audit cycles were completed over 2 years. Improvement was determined by comparing the performance between two six-month periods pre- and post-intervention. Qualitative methods were used to ascertain facilitating and limiting contextual factors influencing change among healthcare professionals' clinical behaviour after the introduction of clinical audit. RESULTS: We found a significant improvement in 11 of 13 criteria in Cuba, in 2 of 6 criteria in Bolivia and in 2 of 5 criteria in Peru. Twelve out of 24 of the audit criteria in all three countries reached the agreed standards. Barriers to quality improvement included conflicting objectives for clinicians and TB programmes, poor coordination within the health system and patients' attitudes towards illness. CONCLUSIONS: Clinical audit may drive improvements in the quality of clinical care in resource-poor settings. It is likely to be more effective if integrated within and supported by the local TB programmes. We recommend developing and evaluating an integrated model of quality improvement including clinical audit.