Calculation Logic for Baseline Model
| Value to calculate | Components used in calculation | Formulae used |
|---|---|---|
| Total annual number of Xpert MTB/RIF tests = Number of tests for HIV+ adults, children, and HIV− adults | Number of tests for HIV+ adults | Estimated number of PLHIVa · 81%b · 2c · 20%d |
| Number of tests for children | Estimated number of children with TBe · 90%f · 4g | |
| Number of tests for HIV− adults | Number of TB patientse,h · 90%f · Percentage of TB patients who are adultse · Percentage of adults who are HIV−a · 10i | |
| Target number of Xpert modules needed | Total annual number of Xpert MTB/RIF tests/68j · 3k |
Abbreviations: HIV+, HIV positive; HIV−, HIV negative; MTB, Mycobacterium tuberculosis; TB, tuberculosis; WRD, World Health Organization-recommended rapid diagnostic.
↵a Source: Joint United Nations Programme on HIV/AIDS.
↵b Target percentage of persons living with HIV who are enrolled on ART (90%· 90%).
↵c Number of TB screening visits per year for clients on ART.
↵d Percentage of clients on ART with symptoms that require testing with a WRD.
↵e Source: World Health Organization.
↵f Target for TB-burden coverage.
↵g Number of symptomatic children needed to test with WRD to diagnose 1 child with TB.
↵h All forms, including all incident, relapse, and previously treated.
↵i Number of symptomatic adults needed to test with WRD to diagnose 1 adult with TB.
↵j Number of days per year that WRD module is operational.
↵k Number of test cycles per day per module.