Consolidated guidance on tuberculosis data generation and use: module 1: tuberculosis surveillance: web annex C: record-linkage exercises

This web annex provides technical guidance on the implementation of record-linkage exercises within tuberculosis (TB) surveillance systems, particularly in countries adopting digital case-based surveillance. It explains the role of record linkage in identifying individuals diagnosed with TB who are not linked to treatment or are missing from notification systems, thereby supporting improved surveillance, programme monitoring and continuity of care. The document describes key concepts and operational steps involved in deterministic and probabilistic record linkage, including data cleaning and standardization, selection of matching variables, blocking, searching and scoring, and manual review of uncertain matches. It also outlines the resources and preparations required for conducting in-country linkage exercises while ensuring confidentiality and appropriate management of sensitive patient data.

The annex includes detailed practical instructions for using the freely available Link Plus application to conduct external linkage and deduplication exercises using simulated TB and laboratory registers. Step-by-step guidance is provided for importing datasets, configuring linkage variables and parameters, reviewing linkage results and exporting merged files. Additional exercises are included to support training and strengthen national capacity for data validation, identification of missed TB diagnoses and enhancement of surveillance system performance.