Validation of sputum smear results in the Electronic TB Register for the management of tuberculosis, South Africa

BACKGROUND: The accuracy of tuberculosis (TB) surveillance systems is paramount in TB control. In South Africa, information from the laboratory is not directly linked to the Electronic TB Register (ETR).

OBJECTIVE: To validate smear results recorded in the ETR with those recorded in the laboratory.

METHODS: A retrospective evaluation was conducted among all sputum smear-positive TB patients recorded in the ETR during the fourth quarter of 2009 in KwaZulu-Natal Province.

RESULTS: Of 1036 smear-positive patients recorded in the ETR, 683 (65.9%) had positive results recorded in the laboratory register. Only 364 (53.2%) had their smear results recorded in the ETR at the end of the intensive phase of treatment; of 326 (89.6%) recorded as converted to smear-negative, 224 (61.5%) were confirmed as smear-negative in the laboratory. Of 331 patients with end-of-treatment results in the ETR, 302 (91.2%) were recorded as cured, but only 105 (34.8%) were confirmed in the laboratory.

CONCLUSIONS: Over a third of TB patients registered as smear-positive in the ETR could not be confirmed based on laboratory results. Many patients did not have a laboratory record, lending to uncertainty as to the validity of the smear results and treatment outcomes recorded in the ETR.