2.3. National Health Laboratory Service

The National Health Laboratory Service was established in 2001 and supports national and provincial health departments in South Africa. It is the largest diagnostic pathology service in the country, providing laboratory and related public health services to over 80% of the population through a national network of 265 laboratories 17. The NHLS performs all public sector CD4 count and VL monitoring and maintains a Corporate Data Warehouse (CDW) that serves as a national repository for laboratory data from the public sector. Healthcare workers at each public health facility complete laboratory requisition forms which accompany each sample submitted to the CDW. All data, including patient identifiers, name of facility, date of sample and tests requested, are sent to the CDW and are captured electronically by the NHLS information system in real time. We have previously evaluated the completeness and accuracy of the NHLS CDW using a novel data crossmatching method 23.