Research Article: A Multi-Country Non-Inferiority Cluster Randomized Trial of Frontloaded Smear Microscopy for the Diagnosis of Pulmonary Tuberculosis

Date Published: July 12, 2011

Publisher: Public Library of Science

Author(s): Luis Eduardo Cuevas, Mohammed Ahmed Yassin, Najla Al-Sonboli, Lovett Lawson, Isabel Arbide, Nasher Al-Aghbari, Jeevan Bahadur Sherchand, Amin Al-Absi, Emmanuel Nnamdi Emenyonu, Yared Merid, Mosis Ifenyi Okobi, Juliana Olubunmi Onuoha, Melkamsew Aschalew, Abraham Aseffa, Greg Harper, Rachel Mary Anderson de Cuevas, Kristin Kremer, Dick van Soolingen, Carl-Michael Nathanson, Jean Joly, Brian Faragher, Stephen Bertel Squire, Andrew Ramsay, Megan Murray

Abstract: Luis Cuevas and colleagues report findings from a multicenter diagnostic clinical trial in tuberculosis, showing that the sensitivity and specificity of a “front-loaded” diagnostic scheme is not inferior to that of a standard diagnostic scheme.

Partial Text: Nine million people developed tuberculosis (TB) and 1.7 million died from the disease in 2008 [1], with over 90% of cases occurring in low- and middle-income countries (LMICs) [1]. Most patients in LMICs are investigated by direct sputum smear microscopy, which, although widely available, has low sensitivity [2] and requires the examination of multiple specimens over several days to maximise the identification of cases [3],[4]. Most national TB programmes (NTPs) collect specimens using a spot-morning-spot (SMS) scheme, whereby patients provide one “on the spot” specimen at the time of consultation, one specimen produced at home the morning of the following day, and a third specimen on the spot when the patient brings the morning specimen to the service. This scheme became widely adopted after a study by Andrews and colleagues in the 1950s concluded that this combination identified the highest number of patients with the lowest number of visits [5]. Since the scheme requires at least two visits, however, patients often abandon the diagnostic process [6]–[8].

TB is a disease of poverty and a global public health emergency [1]. Patients with chronic cough are the main source of infection, and their early identification and treatment are key to effective control [1]. Simple diagnostics suitable for community-based health services would significantly improve TB control activities but unfortunately are not expected to be available in the near future [16]. Smear microscopy thus remains the test most widely used for diagnosis in LMICs.



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