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. 2019 Dec 23;7(4):551–563. doi: 10.9745/GHSP-D-19-00244

TABLE 2.

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.