MRCP2-0981

A 27-year-old male patient complains of a solitary, painless, hardened sore on his penile shaft that has been present for one week. He also reports feeling several small, painless lymph nodes in his groin area on both sides. The patient admits to having had unprotected sexual intercourse with a prostitute three weeks before seeking medical attention.

What laboratory tests can be done to confirm the diagnosis?