I hope this helps somewhat, I pulled it from the CMS Website:
CLAIMS REVIEW AND ADJUDICATION
If another physician covers for the designated attending physician, the services of the substituting physician are billed by the designated attending physician under the reciprocal or locum tenens billing instructions. (See MCM 3060.6 and 3060.7.) In such instances, the attending physician bills using the GV modifier in conjunction with either the Q5 or Q6 modifier. When services related to a hospice patient's terminal condition are furnished under a payment arrangement with the hospice by the designated attending physician, the physician must look to the hospice for payment. In this situation the physicians' services are hospice services and are billed by
the hospice to its intermediary. Process and pay for covered, medically necessary Part B services that physicians furnish to patients after their hospice benefits are exhausted or revoked even if the patient remains under the care of the hospice. Such services are billed without the GV or GW modifiers. Make payment based on applicable Medicare payment and deductible rules for each covered service even if the beneficiary
continues to be treated by the hospice after hospice benefits are exhausted or revoked. The CWF response contains the period of hospice entitlement. This information is a permanent part of the notice and is furnished on all CWF replies and automatic notices. Use the CWF reply for validating dates of hospice coverage and to research, examine and adjudicate services coded with the GV or GW modifiers.
4175.2 Services Unrelated to a Hospice Patients Terminal Condition--You may receive claims from physicians and suppliers for services not related to the hospice patient's terminal condition. These services are coded with the GW modifier “service not related to the hospice patient's terminal
condition.” Process services coded with the GW modifier in the normal manner for coverage and payment determinations. If warranted, you may conduct prepayment development or postpayment review to validate that services billed with the GW modifier are not related to the patient's terminal
condition.
4175.3 Non-Hospice Services Furnished to Hospice Patients Who Are M+C Enrollees.--When an M+C enrolleee elects hospice coverage, you may receive fee for service claims from enrolled M+C organizations, physicians and suppliers who furnish non-hospice services to M+C enrollees.
Process such services for coverage and payment determinations and submit claims transactions to CWF for payment authorization. Pay for medically necessary non-hospice services (i.e., services billed with either the GV or GW modifier) for M+C enrollees who elect hospice coverage based on
applicable Part B payment and deductible rules.
4175.4 Payment Safeguards.--
o Deny services billed by non-attending physicians who treat the hospice patient for the terminal condition. (See §4175.5.)
o Determine if bills for DME, supplies, or independently practicing speech or physical therapists relate to the terminal condition. Deny DME, supplies, and independent speech and physical therapy claims related to the hospice patient's terminal condition. The hospice is required to bill and be paid for these services through it's intermediary. See §4175.2 for handling services
unrelated to the hospice patient's terminal condition.
http://www.cms.gov/transmittals/downloads/R1728B3.pdf[/URL]
You will most likely need to contact this payor for specific rules/guidelines they may have you to follow to resolve your claim. Hopefully this info will arm you for the discussion!
Kelly