Figures & Tables
Tables
- TABLE 1.
Baseline Model Parameters Needed to Calculate Xpert Cartridges and Modules to Identify 90% of Total Estimated TB Cases
Parameter Value Estimated TB burden coverage 90% Type of WRD Xpert MTB/RIF Who receives a WRD? All with TB symptoms Number of adults with symptoms needed to test with WRD to diagnose one adult with TB 10 Number of children with symptoms needed to test with WRD to diagnose one child with TB 4 Number of days per year that WRD (module) is operational 168 Number of test cycles per day per module 3 Estimated percentage of PLHIV enrolled on ART 81% TB screening visits per year for clients on ART 2 Percentage of clients on ART with symptoms that require WRD 20% Abbreviations: ART, antiretroviral therapy; PLHIV, people living with HIV; TB, tuberculosis; WRD, World Health Organization-recommended rapid diagnostic.
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.
- TABLE 3.
Xpert Modules and Test Cartridges Needed Under Baseline Model for 24 High-Burden Countries, by Country
Country Current Number of Modules Total Modules Needed Change Needed from Current (%) No. Test Cartridges (2017) No. Test Cartridges Needed, Annually Change Needed from Current (%) Afghanistan 180 1,146 537% 17,500 577,600 3201% Bangladesh 860 6,229 624% 341,900 3,139,400 818% Cambodia 300 898 199% 134,050 452,700 238% Democratic Republic of the Congo 614 4,368 611% 32,350 2,201,700 6706% Ethiopia 1268 3,111 145% 203,950 1,567,700 669% India 4780 49,986 946% 2,543,150 25,192,700 891% Indonesia 2356 14,545 517% 507,450 7,330,800 1345% Kenya 838 2,914 248% 450,450 1,468,900 226% Kyrgyzstan 80 167 108% 16,200 84,000 419% Malawi 428 873 104% 62,150 440,100 608% Mozambique 368 3,061 732% 150,250 1,542,900 927% Myanmar 367 3,120 750% 41,300 1,572,400 3707% Nigeria 1576 8,182 419% 349,850 4,123,500 1079% Pakistan 2808 9,087 224% 435,050 4,579,900 953% Philippines 1436 10,029 598% 301,200 5,054,500 1578% South Africa 4204 7,027 67% 2,198,000 3,541,500 61% Tajikistan 122 138 13% 133,150 69,600 −48% Tanzania 852 2,866 236% 395,250 1,444,400 265% Uganda 994 1,762 77% 300,850 888,000 195% Ukraine 292 725 148% 80,000 365,200 357% Uzbekistan 208 453 118% 76,100 228,100 200% Vietnam 690 2,230 223% 219,500 1,124,000 412% Zambia 720 1,190 65% 166,850 599,700 259% Zimbabwe 532 1,092 105% 247,900 550,300 122% TOTAL 26,873 135,198 403% 9,404,400 68,139,600 625% Scenario Name Parameter to Change Default Value Effect of Variation on Model Output 1. Current notifications Estimated TB burden 90% If estimated TB burden is reduced to show only the capacity needed for current TB notifications, this will reduce the number of modules needed by a total of 32% (range: 8%–55%). 2. Reduced TB prevalence Number of adults with symptoms needed to test with rapid diagnostic (Xpert) to diagnose 1 adult TB patient (NNT) 10 Number of needed modules changes almost proportionately (e.g., increasing to 12 tests will increase output by up to 19%). As prevalence decreases, the value will increase. 3. More screening of PLHIV Percentage of PLHIV on ART with signs and symptoms of TB that require Xpert test 20% Increasing the percentage to 30% will increase number of modules needed by a total of 6% (range: 0%–38%). 4. Less screening of PLHIV Decreasing to 10% will decrease number of modules needed by a total of 6% (range: 0%–38%). 5. Current screening of PLHIV Decreasing to 2.5% will decrease number of modules needed by an average of 10% (range: 0%–67%). 6. Increased operation of module Operational capacity 168 days/year
3 cycles/dayIncreasing working days to 240 and test throughput to 4 cycles/day will reduce number of modules needed by 48% in all countries. 7. CXR triage Number needed to test 10 Including CXR as a triage tool before the WRD is estimated to reduce the number needed to test to 5 for HIV-negative adults and 2 for children, and to reduce the baseline number of PLHIV on ART requiring Xpert testing by 50%; in total, this would therefore reduce the number of modules and cartridges needed by 50%. See text for justification. 8. Ambitious case finding Number needed to test and operational capacity 10 for NNT; 3 cycles/day To detect all people with TB, more ambitious case finding is needed. This is likely to result in both more down-time for modules (due to greater decentralization and/or using mobile screening, thus cycles/day is reduced to 2) and a lower positivity rate from testing more people with symptoms of TB (thus NNT is increased to 20). This combination of changes increases modules and cartridges needed by 177% and 84% (range: 80%–194% and 20%–96%). 9. WRD sites Access standard for smear microscopy None Converts access standard for smear microscopy (1 microscope/100,000 population) to WRD sites needed to achieve same geographical coverage. This produces a large number of sites needed, though these values are more than 4 times lower than the baseline modules needed, since each site will require multiple modules to achieve sufficient throughput. Abbreviations: CXR, chest X-ray; NNT, Number needed to test; PLHIV, people living with HIV; TB, tuberculosis; WRD, World Health Organization-recommended rapid diagnostic.
Country A: Cost of Additional Xpert Modules (Based on the Price of a 4-Module Instrument) B: Cost of 1 Year’s Supply of Additional Cartridges, According to Total Calculated Need C: Total Incremental Cost of Baseline Model Over Current Situation (New Modules Plus 1 Year of Cartridges) (A+B) D: Total Current Cost (Existing Modules Plus Number of Cartridges Procured in 2017) E: Total % Increase in Investment Needed (C/D) Afghanistan $4,226,389 $5,589,798 $9,816,187 $962,150 1020% Bangladesh $23,489,236 $27,919,050 $51,408,286 $7,174,662 717% Cambodia $2,617,188 $3,180,127 $5,797,315 $2,650,319 219% Democratic Republic of the Congo $16,425,729 $21,650,113 $38,075,842 $3,009,103 1265% Ethiopia $8,061,007 $13,610,225 $21,671,232 $7,582,921 286% India $197,774,132 $226,042,509 $423,816,641 $46,293,137 916% Indonesia $53,327,917 $68,097,033 $121,424,950 $15,371,851 790% Kenya $9,084,618 $10,164,131 $19,248,749 $8,161,741 236% Kyrgyzstan $379,167 $676,644 $1,055,811 $511,676 206% Malawi $1,947,813 $3,771,941 $5,719,754 $2,492,757 229% Mozambique $11,783,229 $13,898,647 $25,681,876 $3,109,495 826% Myanmar $12,043,681 $15,280,378 $27,324,059 $2,017,799 1354% Nigeria $28,899,271 $37,661,027 $66,560,298 $10,386,503 641% Pakistan $27,471,076 $41,365,603 $68,836,679 $16,626,799 414% Philippines $37,593,368 $47,437,934 $85,031,302 $9,288,476 915% South Africa $12,349,688 $13,408,130 $25,757,818 $40,328,540 64% Tajikistan $70,417 $(634,229) $(563,812) $1,862,587 -30% Tanzania $8,810,694 $10,470,517 $19,281,211 $7,672,095 251% Uganda $3,359,583 $5,859,757 $9,219,340 $7,351,233 125% Ukraine $1,892,639 $2,846,296 $4,738,935 $2,075,900 228% Uzbekistan $1,070,035 $1,516,960 $2,586,995 $1,669,478 155% Viet Nam $6,738,194 $9,026,910 $15,765,104 $5,209,360 303% Zambia $2,055,729 $4,319,843 $6,375,572 $4,815,163 132% Zimbabwe $2,449,410 $3,017,952 $5,467,362 $4,801,542 114% TOTAL $473,920,208 $586,177,296 $1,060,097,504 $211,425,287 AVERAGE $19,746,675 $24,424,054 $44,170,729 $8,809,387 474%
Additional Files
Supplemental material
- Supplement -
Full Data on the Xpert MTB/RIF Module and Cartridge Needs Under the Sensitivity Analysis Scenarios
- Supplement -
