G0001 is pap collection, payable by Medicare, but not many others. Lab collection fees are as Michele stated: 36415 for a venipuncture; 36416 for a finger or heel stick; 99000 for handling and conveyance of specimen for transfer from the office to a lab; 99001 for handling and conveyance of specimen from patient in non-office setting to a lab.
It should be noted that 99000 and 99001 do not mean putting the specimen in the lab box for them to come pick up, it is meant for rush handling directly to the lab.
It should also be noted that very, very few companies remiburse the lab handling fees.