I had asked for some further information and have not heard back, but I have to run to the Health Center, so will address what information is available.
I asked about the total white blood count to determine the absolute number of lymphocytes. Since the total white blood count is the sum of several different types of white blood cells, an increased percentage of any particular white blood cell can be due to an increase in the number of that type of white blood cell or a decrease in the other types of white blood cells, particularly the neutrophils (which are the largest portion of the total white blood cells).
If the number of lymphocytes is increased, then the most likely cause is a viral infection. There is a very small risk that the increase is due to cancer, but doctors will usually only be concerned about the possibility of cancer if the number is XXXXX high or if a lower elevation is more persistent. If there are immature forms of any white blood cell present, that would be more of a concern, but these would not be reported as lymphocytes. Ultimately, the proof that this is due to an infection is that a repeat test will be normal.
If the percentage is high because of a decrease in other white blood cells, then this is frequently nothing to be concerned about and is not a potential sign of lymphatic cancer. Whether this is a concern for anything in this scenario would depend upon the absolute number of each respective type of white blood cell.
If you have any further questions, please let me know. I will be back online later today.