Samuel D. Yoo

Learn More
Laboratory methods to improve smear microscopy are an urgent priority for global tuberculosis control. The novel universal sample processing (USP) method has been reported to improve conventional diagnostic testing for tuberculosis while also providing inhibitor-free specimens for molecular assays. However, no studies evaluating the method in the field have(More)
BACKGROUND Sputum concentration increases the sensitivity of smear microscopy for the diagnosis of tuberculosis (TB), but few studies have investigated this method in human immunodeficiency virus (HIV)-infected individuals. METHODS We performed a prospective, blinded evaluation of direct and concentrated Ziehl-Neelsen smear microscopy on a single(More)
SETTING Mulago national referral and teaching hospital. OBJECTIVE To assess the etiology of lower respiratory infections in HIV-infected Ugandan adults who are sputum acid-fast bacilli (AFB) smear-negative. DESIGN A descriptive cross-sectional study. Participants included consecutive adult patients admitted to medical wards with respiratory symptoms of(More)
SETTING Mulago Hospital, Kampala, Uganda. OBJECTIVE To evaluate the diagnostic performance of fluorescence microscopy (FM) for diagnosing pulmonary tuberculosis (TB) in a high human immunodeficiency virus (HIV) prevalence setting. DESIGN Consecutive in-patients with cough for >2 weeks submitted two sputum specimens for smear microscopy. Smears were(More)
BACKGROUND Respiratory infections are a leading cause of death in Africa, especially among HIV-infected patients. Data on the etiology of fatal respiratory diseases are largely based on autopsy studies. We evaluated causes of pneumonia associated with early mortality among hospitalized HIV-infected patients in Kampala, Uganda. METHODS Prospective cohort(More)
Pneumocystis jirovecii pneumonia (PCP) is an important opportunistic infection in patients infected with HIV, but its burden is incompletely characterized in those areas of sub-Saharan Africa where HIV is prevalent. We explored the prevalence of both PCP in HIV-infected adults admitted with pneumonia to a tertiary-care hospital in Uganda and of putative P.(More)
BACKGROUND Although World Health Organization guidelines recommend clinical judgment and chest radiography for diagnosing tuberculosis in HIV-infected adults with unexplained cough and negative sputum smears for acid-fast bacilli, the diagnostic performance of this approach is unknown. Therefore, we sought to assess the accuracy of symptoms, physical signs,(More)
BACKGROUND Peripheral blood interferon-gamma release assays (IGRAs) have sub-optimal sensitivity and specificity for diagnosis of active pulmonary tuberculosis (TB). However, assessment of local immune responses has been reported to improve the accuracy of TB diagnosis. METHODS We enrolled HIV-infected adults with cough ≥2 weeks' duration admitted to(More)
RATIONALE Smear-positive tuberculosis (TB) case detection rates are far below targets in most low-income countries. The standard approach to smear microscopy involves sputum collection over multiple days and examination of sputum smears by light microscopy (LM), an insensitive and time-consuming technique. OBJECTIVE To determine whether two alternative(More)
BACKGROUND T-cell interferon-gamma release assays (IGRAs) may have a role in the diagnosis of active tuberculosis when evaluating patients for whom standard microbiology has limited sensitivity. Our objective was to examine the accuracy of a commercial IGRA for diagnosis of active tuberculosis in HIV-infected persons. METHODS We enrolled HIV-infected(More)