This is a modifier PT fact sheet that I believe will answer your questions. If it is a commercial payer you may need to contact them directly to see if they accept this modifier or how they would like it billed.
http://www.wpsmedicare.com/j5macpartb/resources/modifiers/pt_modifier.shtm
Modifier PT Fact Sheet
Definition:
A colorectal cancer screening test which led to a diagnostic procedure
Appropriate Usage:
When a service began as a colorectal cancer screening test and then was moved to diagnostic test due to findings during the screening
Practitioners should append the modifier to the diagnostic procedure code that is reported instead of the screening colonoscopy or screening sigmoidoscopy HCPCS code
Append to surgical procedure codes in the range: 10000 to 69999 or G6018-G6028
Append to anesthesia procedure code 00810
Inappropriate Usage:
Do not use the Modifier PT when the service began as a diagnostic procedure
On any other procedure code not listed above
CMS Resources
CMS MLN Matters Article MM7012
Note: The Medicare policy is that the deductible is waived for all surgical procedures furnished on the same date and in the same encounter as a colonoscopy, flexible sigmoidoscopy, or barium enema that were initiated as colorectal cancer screening services.