Peterson Laboratory Services is happy to provide billing services for you and your patients. You may choose to have testing services billed to you as a health care provider, or directly to your patient. MEDICARE: We are a Medicare participating provider. Therefore, we must bill Medicare directly for any services performed directly by our laboratory. Diagnosis codes justifying medical necessity are required by Medicare for reimbursement of many laboratory tests. Medicare patients should sign an Advanced Beneficiary Notice (ABN) form when any laboratory work is ordered for screening purposes, or when a diagnosis code that does not justify medical necessity is being used. Check the Medicare National Coverage Determinations manual. If the code is not covered, have the patient sign the ABN.