Would blood flow cytometry and peripheral blood smear tests more than likely detect leukemia and lymphoma? normal results. person also had normal ct scans so no swollen nodes, only persistent mild lymphocytosis as the reason for these tests?

Blood tests: A simple cbc and differential cell count is usually diagnostic of leukemia, but peripheral blood tests aren't helpful in diagnosis of lymphoma which requires a tissue diagnosis. I suspect your lymphocytosis, if mild, is nonspecific. I assume active viral infections and infectious mononucleosis are not issues at this time. A hematologist is best to advise you.