Evaluation of diagnostic performance of non-invasive HIV self-testing kit using oral fluid in Addis Ababa, Ethiopia: A facility-based cross-sectional study.

BACKGROUND: Human immunodeficiency virus (HIV) testing is critical for early linkage to treatment and care services. However, there is a substantial gap in HIV testing, particularly in resource limited settings due to low accessibility of HIV testing sites, inconvenient testing hours, and concerns about loss of confidentiality. Thus, adopting new strategies such as HIV self-testing (HIVST) could overcome these barriers and increases HIV testing uptake. OBJECTIVE: The aim of this study was to evaluate the diagnostic performance of non-invasive HIVST kit using oral fluid for HIV diagnosis. This study also aimed to assess the ability of clients in interpretation of OraQuick HIVST results. METHOD: Between December 2017 and February 2018, a total of 400 study participants were enrolled into the study to assess a diagnostic accuracy of Oral fluid-based HIVST kit (OraQuick) in 15 public health facilities in Addis Ababa, Ethiopia. Participants were provided with instructions and visual aids on how to perform HIVST and interpret results. They also underwent a blood-based rapid HIV antibody test as per the current national algorithm. The results of HIVST were interpreted independently by the participants and respective health care workers (HCWs). The sensitivity, specificity, positive predictive value (PPV), Negative predictive value (NPV) and inter-rater agreement of the test were computed. RESULTS: Out of 200 participants who tested positive on the national algorithm testing, oral fluid-based self-testing was positive in 199 (99.5%), false negative in 1 (0.5%). Of 200 participants who tested negative on the national algorithm testing, self-testing was negative in 200 (100%). There were no false positive and invalid tests. The sensitivity and specificity of the OraQuick HIVST were 99.5% (95%CI: 97.26-99.99) and 100% (95%CI: 98.18-100.0), respectively. The overall agreement between the two tests was high (κ value = 0.995). The PPV and NPV of OraQuick test were 100% and 99.5% (95%CI: 96.59-99.93) respectively. CONCLUSION: This study showed a high diagnostic performance of OraQuick HIV self-test and suggests that OraQuick HIVST kit has a potential to be used for HIV testing in Ethiopia along with the national algorithm.

Improved tuberculosis smear detection in resource-limited settings: Combined bleach concentration and LED fluorescence microscopy.

Improved diagnostics for tuberculosis is a high priority in resource-limited settings (RLS). Sputum concentration and fluorescence microscopy (FM) are standard techniques in developed countries where appropriate biosafety precautions are possible. Recently, inexpensive fluorescent lenses using LED light sources have made auramine-based FM more feasible in RLS. Sterilization of sputum with bleach protects lab personnel and, combined with concentration, increases the sensitivity of microscopic detection. We compared the effect of both bleach concentration and FM with LED based lenses to culture for the detection of tuberculosis in military medical hospitals in Addis Ababa, Ethiopia. Three sputum specimens were obtained from 409 patients (1227 total). Standard Ziehl-Neelsen (ZN) or auramine staining were compared with direct or bleach-concentrated specimens. The prevalence by culture was 26%. Sensitivity of microscopic diagnosis was increased both by bleach concentration (14%) and auramine staining (5%). The overall yield of smear positivity varied from 21% for direct ZN to 27% for auramine after concentration (P<0.00001, Cochran test for matched proportions). Twenty-nine HIV+ patients were diagnosed with TB, but ten (34%), would have been missed with direct ZN staining. Bleach concentration and auramine staining with new LED fluorescent systems are cost-effective and safe methods to increase the diagnostic yield of smears, including in HIV-infected patients.

Detection of acid fast bacilli (AFB) in tuberculous lymphadenitis among adult Ethiopians.

BACKGROUND: The sensitivity of conventional methods used in mycobacteriology laboratories may not exceed 40% in extrapulmonary cases of tuberculosis. Fine needle aspiration cytology (FNAC) is the best and affordable alternative method of diagnosing tuberculous (TB) lymphadenitis. However detection of acid fast bacilli (AFB) remains the corner stone of confirming diagnosis of TB. OBJECTIVES: To investigate the detection rate of AFB in FNAC specimens using the Ziehl Neelsen staining method and see if bacillary detection depends on cytomorphologic features of inflammation. METHODS: All consecutive adult patients having solitary or multiple peripheral lymphnode enlargements and diagnosed cytologically as TB lymphadenitis were included in the study. Aspirated samples were expressed on two glass slides and one is stained with Wright's stain for cytology, while the other is stained using the Ziehl Neelsen method for AFB. Cytologic findings were categorized in to three groups as non-caseating granuloma, caseating granuloma and pyo-histiocytic inflammation. RESULTS: Only 52 (21.9%) aspirated samples were found to be positive for AFB. The most interesting finding in this study is that among the 52 AFB positive cases, 47 (53.4%) were cytomorphologically of the pyo-histiocytic type. CONCLUSION: Detection of AFB varies with the cytomorphology of inflammation, being very high in pyo-histiocytic type.