Diagnostics
HIV Point of Care tests in Babies Study (BABY)
Operational evaluation of HIV Point of Care tests for very early infant HIV diagnostics in infants born to HIV infected mothers in Mbeya, Tanzania
HIV in infants is mainly vertically transmitted by infected mothers and is associated with high mortality rates if no antiretroviral treatment is provided. Accurate HIV diagnosis in infants is only feasible by detection of HIV nucleic acid (HIV-RNA or -DNA) and therefore HIV early infant diagnostic (EID) screening is routinely performed at the age of 6 weeks from dried blood samples requiring specialized laboratory facilities and multiple step linkage procedures for result dissemination. In the present BABY study HIV point of care tests (POC) will be evaluated in infants born to HIV infected mothers to evaluate for the operational feasibility as well as specificity, sensitivity and predictive values to detect infant HIV at birth, weeks 1, 2, 3 and 6. The rationally is to implement infant HIV bed side tests at obstetric/maternity clinics providing immediate diagnostic test results and in consequence avoiding the need of specialized laboratory facilities as error prone linkage procedures. Furthermore, the possibility of infant HIV diagnosis as early as the time of birth opens the possibility for earlier infant antiretroviral treatment initiation resulting into a possible further reduction of HIV related infant mortality/morbidity.
Development and Evaluation of New TB Diagnostics
Project Coordinator: Andrea Rachow, MD
In collaboration with FIND-Diagnostics (Geneva), Chemogen Inc. (USA), University College London (UCL), University of Cape Town (UCT) and other partners, new diagnostics for simple and rapid detection of TB and drug resistance in adults and children are being developed and evaluated.
Currently, the portfolio in evaluation comprises PCR-based methods directly from smear positive sputum or positive culture, such as Xpert MTB/RIF Assay®, Hain MTBDRplus® and LAMP. Additionally we further evaluate IFN-y release assays (IGRAs) and different ELISAs for their performance in detection of childhood TB. Moreover new markers for TB treatment course and their capability of predicting treatment outcome are under investigation. Together with UCL transrenally excreted mycobacterial DNA is evaluated as biomarker for anti TB- treatment course. Furthermore TB-diagnosis by stool PCR will be established at the site with the aim to improve DNA-extraction methods and diagnostic accuracy of existing PCR-strategies. In a joined research project with UCT out of other research question the performance of a new generation of urine LAM-ELISA and its impact on TB-diagnostic in resource constrained countries is investigated.
As reference standard we use culture on solid and liquid media followed by molecular species determination and drug susceptibility testing using the Bactec MGIT-system performed in our state-of-the art tuberculosis laboratory.
Transrenal DNA detection for TB Diagnosis
Coordinator: K. Reither MD, Msc
Background / Purpose:
Tuberculosis (TB) is a global threat to public health. The lack of accurate, rapid, inexpensive and convenient tests for tuberculosis still hinders patient management and disease control. The potential diagnostic capability of cell-free transrenal DNA (Tr-DNA), short DNA fragments which pass the renal barrier, has been demonstrated in infectious diseases, including TB, HIV, and malaria.
The main objectives of the project are to evaluate the potential of transrenal DNA detection in urine specimen for diagnosis of tuberculosis, to optimize and simplify the assay and the specimen preparation, and to explore the suitability of the new technology in a developing world setting. The overall goal will be to obtain the knowledge to develop a robust, accurate and rapid procedure to diagnose TB on the basis of Tr-DNA.
E-nose
Coordinatior: K. Reither, MD, Msc
Background / Purpose:
The lack of accurate, rapid and convenient tests for tuberculosis (TB) still hinders patient management and control of this deadly disease.
In most parts of the developing world, the microscopy smear test is the only affordable and feasible method to detect TB. However, the sensitivity and specificity of this test are highly variable and the procedures are very time- and labor-intensive. Other technologies, as for instance culture or molecular biological methods, are expensive and technically very difficult and thus are not applicable on a large scale in resource poor countries.
One of the technologies which might fulfill the requirements for a new diagnostic tool for TB is the electronic nose. It mimics the human olfactory system using chemical sensors which recognize patterns in the volatiles of samples. Advantages of the electronic nose, among others, are the simple sample preparation and the fact that no reagents or other expensive consumables are required. Additionally, results are available very quickly, which would facilitate the prevention of transmission of the disease and speed up treatment initiation.
The purpose of this project is the preclinical and clinical evaluation of an electronic nose for diagnosing pulmonary tuberculosis. The sampling method, as well as data reproducibility, sensitivity and specificity of the technology will be assessed and improved.
Rapid Direct Antigen Test for Tuberculosis
Coordinator: C. Boehme PhD
Lab Coordinator: M. Gerhardt PhD
Lab Coordinator: S. Dufke
Purpose:
The main purpose of the proposed project is the development and clinical evaluation of a rapid direct antigen test for diagnosis of pulmonary tuberculosis using an immunochromatographic test format. One major obstacle in the fight against tuberculosis is the lack of an inexpensive, easy to use and sensitive method to detect TB infected patients. The only method that is affordable in many parts of the developing world is the microscopy smear test. It is used to detect TB-patients and monitor their treatment success. Unfortunately this test is labour intensive and is mainly used to detect “productive, open”, pulmonary TB. In addition, the sensitivity depends dramatically on the quality of the test performers. More advanced methodologies such as culture and PCR are technically difficult, not that reliable and therefore not widespread in rural Africa.
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