The problem of a decision support of a laboratory service patients originates from the fact that in Russia most patients address laboratory services directly without being referred by a doctor. This leads to the problem of interpretation of test results by the patients without sufficient medical background. So, we have a situation when there is no doctor who can professionally interpret the results. This problem can be solved by a laboratory service if it can provide not only the results of the tests but also their interpretations. This task can be delegated to a decision support system, which can automatically generate interpretation reports and send them to the patients. We have implemented and evaluated such a system in the Helix laboratory service in Saint-Petersburg, Russia. Now, it generates about 3500 reports a day. The implementation of the system allowed increasing the number of patients who refer to a doctor after laboratory tests by 14%. A qualitative study with 100 patients demonstrated a high acceptance of the system. The majority (82%) of the patients reported that they trust the system and follow its advice to visit a doctor if necessary.