CEACAM5 and neoplasm: Laboratory workup showed normal tumor markers, including CA19-9 at 20.9 IU/mL (N < 37), carcinoembryonic antigen (CEA) at 2.4 ng/mL (N < 7 for smokers), and lactate dehydrogenase (LDH) at 146 IU/L (N = 110–265).