GLOBAL TB PROGRAMME

Systematic screening for

active TB – operational

manual and tool to help

prioritization

Wolfheze 2015

Knut Lönnroth, Global TB Programme,

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GLOBAL TB PROGRAMME

Strong recommendations =

Should be screened in all settings

1. Household contacts and other close contacts should be systematically screened for active TB.

2. People living with HIV should be systematically screened for active TB at each visit to a health facility.

3. Systematic screening for active TB should be done in current and former workers in workplaces with silica exposure

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Conditional recommendations =

prioritization needed

4. Systematic screening for active TB should be considered in prisons and other penitentiary institutions. (including staff)

5. Systematic screening for active TB should be considered in people with untreated fibrotic CXR lesion.

6. In settings where the TB prevalence is ≥100/100,000 in the general population, systematic screening for active TB should be considered among people who are seeking care or who are in care and belong to selected risk groups (see remarks, including staff)

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Conditional recommendations, cont.

7. A. Systematic screening may be considered for geographically defined sub-populations with extremely high levels of undetected TB (>1% prevalence)

B. Systematic screening may be considered also for other sub-populations with very poor health care access, such as urban slum dwellers, homeless people, people living remote areas with poor access, indigenous populations, migrants, and other vulnerable groups.

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Operational guide

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Planning & implementation cycle

1. Situation assessment /

6. Monitoring and evaluation

2. (Re-)Define goals and specific

objectives

3. (Re-) prioritization of

risk-groups

4. Choose screening and

diagnostic algorithms

5. Planning, budgeting,

implementation

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Tool for prioritization of risk groups (slides from Cecily Miller, UCSF)

Estimates the following for each risk group and each algorithm:

Case-finding yield (true and false positive)

Number needed to screen to detect one true case

Total cost

Cost per true case detected

Allows for comparison of estimates Across risk groups

Across screening algorithms

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Step 1– Select the country

User begins by selecting the country for exploration:

Country selection auto-populates data on:

Total population size

TB prevalence per 100,000

HIV prevalence

Household size (when available)

Cambodia

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Step 2 – Select risk groups

PLHIV

Contacts

Miners

Diabetics

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Step 3 – Estimating risk group size

2 ways to specify population size of selected risk groups:

1. Estimate size of risk group as % of country population (default)

2. Estimate absolute size of risk group

PLHIV

Contacts

Miners

Diabetics

GLOBAL TB PROGRAMME

Step 4 – Estimating TB prevalence

in each risk group

2 ways to specify TB prevalence within risk groups:

1. Enter or estimate relative risk of TB in risk group compared to

general population (default)

2. Enter or estimate absolute TB prevalence per 100k

PLHIV

Contacts

Miners

Diabetics

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Step 5 – Reachability & acceptability

Contacts

PLHIV Miners

Diabetics

Enter the % of the risk group expected to be reachable

Enter the % of the risk group expected to accept screening

Findings from acceptability systematic review pre-filled as suggested

values

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Algorithms (default, with changeable

values for sensitivity and specificity) 1a. Cough screen Sputum smear microscopy

1b. Cough screen Xpert

1c. Cough screen CXR Sputum smear microscopy

1d. Cough screen CXR Xpert

2a. Any symptom screen Sputum smear microscopy

2b. Any symptom screen Xpert

2c. Any symptom screen CXR Sputum smear microscopy

2d. Any symptom screen CXR Xpert

3a. CXR Sputum smear microscopy

3b. CXR Xpert

Note: - Clinical diagnosis / empirical treatment considered for persons negative on diagnostic test for all algorithms

- Culture can be included, by replacing Xpert assumptions

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Step 6 – costs

User estimates cost of per person

screened:

1. Test cost

2. Operational cost

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https://wpro.shinyapps.io/screen_tb/

Developed by Knut Lönnroth, Cecily Miller and Nobu Nishikiori

Programmed in RStudio by Nobu Nishikiori

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Total yield

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GLOBAL TB PROGRAMME

No. of true and false positive cases

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scopy

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Costs per true case, across algorithms:

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Incremental cost-effectiveness

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Tool considerations & limitations

Focus on pulmonary TB (bacteriologically confirmable)

The tool is exploratory, not for detailed planning purposes Tool estimates are based on several assumptions

The uncertainty of each estimate compounds the uncertainty of the overall estimates

Does not model the impact on transmission and TB incidence

Does not estimate patient cost (only provider)

Algorithm options developed mostly for low- and middle-income countries

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Thank you

Acknowledgements

Cecily Miller

Nobu Nishikiori

Screening operational guide review committee