Reflective testing is a procedure in which the laboratory specialist adds additional tests and/or comments to an original request, after inspection (reflection) of the results. It can be considered as an extension of the authorization process where laboratory tests are inspected before reporting to the physician. The laboratory specialist will inevitably find inconclusive results, and additional testing can contribute to make the appropriate diagnosis. Several studies have been published on the effects of reflective testing. Some studies focus on the opinion of the general practitioners or other clinicians, whereas other studies were intended to determine the patient's perspective. Overall, reflective testing was judged as a useful way to improve the process of diagnosing (and treating) patients. There is to date scarce high quality scientific evidence of the effectiveness of this procedure in terms of patient management. A randomized clinical trial investigating this aspect is however ongoing. Cost effectiveness of reflective testing still needs to be determined in the future. In conclusion, reflective testing can be seen as a new dimension in the service of the clinical chemistry laboratory to primary health care. Additional research is needed to deliver the scientific proof of the effectiveness of reflective testing for patient management.