Tuberculosis (TB)

WHO Global Task Force on TB Impact Measurement

Frequently-asked questions

What can be done to improve the TB surveillance and monitoring and evaluation system in my country?

Frequently-asked questions

The list below provides some important examples of activities and related studies that can help to improve surveillance and monitoring and evaluation systems.

1. Improve recording and reporting capacity:
  • Improve coverage of recording and reporting
  • Improve supervision of recording and reporting activities, from data collection to data validation to data analysis and reporting of findings
  • Introduce a new or improve the existing electronic recording and reporting system
2. Improve capacity to analyse TB notification and other supporting data at
  • National level
  • Sub-national level
3. Improve feedback of data analysis and interpretation to TB staff and other health care staff working at the peripheral level
4. Implement a study to identify and eliminate duplicate and misclassified records at national level

... so that such records do not artificially inflate the number of new TB cases that are recorded and reported

5. Perform data quality assessment

(e.g. using available tools for assessment of data quality)

6. Perform studies:
  • of the number of TB cases as a proportion of the number of suspects examined and/or
  • of the number of suspects examined as a proportion of the number of chronic respiratory cases attending health care facilities

These studies can help to identify the extent to which TB cases are being missed in some health care facilities as compared with others, and the reasons for this.

7. Perform contact investigation studies in a sample of health care facilities.

The aim here would be to estimate the total number of cases that could be found among contacts of TB cases. For example, suppose that a contact investigation study was conducted in 1% of all health care facilities, and that for every 100 index patients who had their close contacts examined 1 new TB case was found. By comparing the characteristics of the index patients and of the general population in the sampled and non-sampled health care facilities, it would then be possible to estimate the total number of new TB cases that could be found among contacts of TB cases diagnosed in the remaining 99% of health care facilities.

8. Perform cross-validation of TB notification data with other sources of TB data:
  • Other pre-existing sources (such as vital registration data, TB laboratory registers, HIV notification register, hospital registers, electronic versus paper-based TB notification registers)
  • Prospectively collected TB data (for example, introduce new registries to be completed by a sample of non-NTP providers)

These cross-validation studies, which are also called inventory studies, can be used to find cases which are not in the NTP notification registry.

9. Capture-recapture studies

By comparing several sources of TB cases, the capture-recapture methodology can be used to estimate the total number of TB cases (i.e. to estimate not only cases that are missing from notifications, but also to estimate the number of cases that are missing from all sources, i.e. cases that are not in contact with health facilities at all).

10. Perform a national survey to estimate the prevalence of drug-resistant TB
11. Perform a national survey of the prevalence of HIV prevalence among registered TB patients
12. Perform a national survey of the prevalence of TB disease
13. Perform studies to assess TB burden in high risk populations (e.g. prisons)
14. Perform studies to quantify the effect of risk factors for TB and their population attributable fraction in your country (for example, HIV, diabetes, and smoking)

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