Had labs done and everything was normal except for lymphocytes at 48.1% (19-48). no cold/flu. what does this mean? should i be concerned?

Numbers are just...: Numbers are just numbers. Without the whole picture, such as why was labwork done, numbers usually cannot tell much. The result value in this question may be fine for a normal person with no symptoms, but one should still ask his ordering doctor if the result is ok in the setting of his whole picture. The patient's ordering doctor knows why the test was ordered, and which results would be ok.