CPT® codes for genetic counseling sessions

Can anyone tell me what they think is the appropriate code(s) for the following situation?

Pt is seen in the office for genetic counseling by a genetic educator (not licensed counselor) and buccal specimen is collected via "swish, spit and run" collection. ? 9940X or 9921X ?

Pt returns 3 weeks later to receive results and discuss options. ? 9940X or 9921x?

I cannot differentiate between the two codes.

Can a provider charge more than one 9940xs within the same year?

Thank you for your asssistance.