A321 First Officer reported a fume event during approach which he characterized as 'dirty socks'. Fumes persisted until gate arrival.

Narrative

Descending through 4;000 ft. the Captain and I smelled a 'dirty socks' smell in the flight deck; but there was also a slight chemical smell to it. I began to feel a tingling sensation in my hands and so I donned my oxygen mask. I was leveling at 3;000 ft. and turning base to final to land on the ILS for XXL. While on oxygen; I felt fit to continue to flying the aircraft and landed normally. I stayed on oxygen until engine shutdown at the Gate. The smell continued on the taxi and lingered after engine shutdown. The Flight Attendants could not smell the odor in the cabin. After I left the aircraft; while walking up the jet bridge my hands; feet; and lips continued to feel tingly and I had a light headed sensation. I elected to go to the ER where my bloodwork confirmed my carbon monoxide levels were slightly elevated. I believe that the fume problem was caused by engine oil contaminants in the bleed air system. However; maintenance could not duplicate the issue and the airplane was returned to service. This type of fume incident is not uncommon throughout the industry and needs to be reported on FAA Service Difficulty Reports to ensure that the industry and manufactures improve the filtration systems on aircraft; install carbon monoxide or other sensors to detect air quality issues; and to develop standardized protocols for physicians to follow when crew members encounter fume events. The health of crew members and the safety of flight is impacted by these fume events and it needs to be corrected.