Below is from CMS so honestly either choice is correct. Either the date of collection or the date of interpretation:
Surgical and anatomical pathology services may have two components: a professional and a technical component. These services will have a PC/TC indicator of "1" on the MPFS Relative Value File. The technical component is billed on the date the specimen was collected. This would be the surgery date. When billing a global service, the provider can submit the professional component with a date of service reflecting when the review and interpretation is completed or can submit the date of service as the date the technical component was performed. This will allow ease of processing for both Medicare and the supplemental pavers. If the provider did not perform a global service and instead performed only one component, the date of service for the technical component would the date the patient received the service and the date of service for the professional component would be the date the review and interpretation is completed.