We describe a monitoring system at population level of patients on antiretroviral therapy (ART) using centrally collected laboratory data. We demonstrate an analogous process of remote sensing using a large set of laboratory results and illustrate the tremendous density of information stored. We moved from an individual to a community view of ART rollout, similar to remote sensing used in the earth and biological sciences when the spatial scale of the investigation is too large to be performed at ground level. This was a retrospective cohort study of patients from January 2004 to June 2011. A total of 188 759 individual laboratory results representing 26 445 patients were analysed for average CD4 and viral load by year. The data showed an increasing state of health of the population and allowed for hypothesis generation when the trends did not follow expected paths. In this analysis we moved away from individual-centred data to population-level data in order to assess ART programme performance. Routine patient-monitoring data had great utility in assessment of population health. These methods are useful in monitoring and evaluation and effectiveness studies as they are easy to collect, reliable (not requiring much human matching or interventions) and scalable from a single clinic to an entire population. The larger the sample size, the more reliable the results, as confounders (such as incorrectly identified transfers out, lost-to-follow-up patients and transfers in) would be removed.