SMF to Improve Performance of Microscopy for the Diagnosis of PTB in a High HIV Prevalence Setting
SMF to Improve Performance of Microscopy for the Diagnosis of PTB in a High HIV Prevalence Setting
This study is investigating a better method to see if someone has tuberculosis (TB) as
 compared to the method that is being used now.
TB is a disease caused by a bacterium called Mycobacterium tuberculosis that can affect the
 lungs or other parts of the body. In most of the world and in Mbarara, Uganda, the method of
 diagnosis that is used is AFB smear microscopy. This method is widely available, inexpensive
 and rapid. However, this method's ability to truly detect people having TB is poor. That is,
 if someone has TB, the test results may say that they are negative, leading to delays in
 diagnosis, disease progression, and an ongoing transmission of the bacteria.

 The new test for TB diagnosis we are studying is called the Small Membrane Filtration (SMF)
 method. This test that is being compared to the method currently being used and is very
 similar to the one that is currently used (standard smear microscopy) but has the advantage
 of concentrating the sputum (mucus) so that we can more easily see if bacteria are present in
 the sputum. It is hoped that a better way of knowing if someone has TB will help doctors
 decide when people need to be treated for TB and when not, which will improve the health of
 patients and help avoid passing the infection to others.

 This study will enroll 740 HIV-infected and 310 HIV-uninfected adults with culture confirmed
 pulmonary TB. These individuals will be identified prospectively at two TB clinics in
 Mbarara, Uganda.

 Study hypothesis: The investigators will assume that one sputum sample will be equivalent to
 two (null hypothesis) with respect to sensitivity unless we have evidence that the use of two
 has higher sensitivity (alternative hypothesis). The investigators will assume that SMF is
 equivalent to AFB smear with respect to sensitivity and specificity unless the investigators
 find evidence it is superior. The investigators will assume that SMF is equivalent to Xpert
 unless the investigators find evidence that Xpert is superior.
Inclusion Criteria:

 -  Adult (≥18 years)

 -  Pulmonary TB suspect defined as any person who presents with a productive cough for
 more than 2 weeks AND accompanied by at least one other respiratory symptom (shortness
 of breath, chest pains, hemoptysis) and/or constitutional symptom (loss of appetite,
 weight loss, fever, night sweats, and fatigue) (6).

 -  Willing to undergo TB evaluation and spontaneously expectorate ≥2 mL of sputum

 -  Willing to be tested for HIV, if no results available within past 6 months

 Exclusion Criteria:

 -  Too ill or unable to provide written consent

 -  Treated with TB drugs for more than 3 days

 -  Extra-pulmonary or disseminated TB without pulmonary involvement (i.e. no cough)