Conclusions: Adding laboratory data exchange interfaces within existing EHRs holds promise for improving HIV care, both in the timeliness of responses to important laboratory results and in the quality of provider communication about lab tests. However, the benefits from this incremental change may be modest unless more extensive redesign of laboratory follow-up workflows is undertaken, with support from enhanced user interfaces that take advantage of the laboratory information delivered. Providers should also consider increased staffing to compensate for dips in follow-up performance during the initial post-implementation months. (Source: International Journal of Medical Informatics).