Billing and Collections Q&A

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By Lisa Lake-Salmon

Denials are difficult to identify and time-consuming to appeal. When denials have you at your wit's end, "Got FAQs?" can help you get your billing back on track. This month's column addresses your questions about medical necessity for codes L-1840 and L-1844, and obtaining infomation on last date of service for diabetic shoes and inserts for Medicare patients.

Q: I recently received denials for L-1840 (knee orthosis, derotation, medial-lateral, anterior cruciate ligament, custom fabricated) and L-1844 (knee orthosis, single upright, thigh and calf, with adjustable flexion and extension joint [unicentric or polycentric], medial-lateral and rotation control, with or without varus/valgus adjustment, custom fabricated). The Medicare representative told me that the diagnosis (DX) code did not meet the medical necessity criteria for this device. I was also told that I did not use the proper modifiers. Can you help me to better understand billing guidelines for these devices?

A: L-1840 is covered for DX code 717.81-717.9 (instability due to internal ligamentous disruption of the knee). L-1844 and L-1846 (knee orthosis, double upright, thigh and calf, with adjustable flexion and extension joint [unicentric or polycentric], medial-lateral and rotation control, with or without varus/valgus adjustment, custom fabricated) are covered for patients who are ambulatory and have knee instability due to any of the following DX codes: 340, multiple sclerosis; 342.9, hemiplegic, unspecified; 343.9, infantile cerebral palsy, unspecified; 344.1, paraplegia of both lower limbs; and 355.0-355.2, mononeuritis of lower limb, unspecified. L-2385 (addition to lower extremity, straight knee joint, heavy duty, each joint) and L-2395 (addition to lower extremity, offset knee joint, heavy duty, each joint) are covered only for patients who weigh more than 300 pounds. When billing any of the above codes to Medicare, you must include an RT or LT modifier as well as a KX modifier.

Q: We are a provider of diabetic shoes and inserts in Alabama. The majority of our patients have Medicare as their primary insurance, and this month, we have received seven denials with claim adjustment reason code CO 150 (payer deems the information submitted does not support this level of service) with remittance remark code M3 (equipment is same or similar as equipment already being used). When patients come to our office, we specifically ask for the last date they received shoes and inserts, and we notate the patients' charts. We provide the service based on the information provided by the patient. Is there a way to avoid receiving these denials and verify when the patient last received a device paid by Medicare prior to dispensing it to the patient?

A: Medicare Region C has an Interactive Voice Response (IVR) System to assist you; call 866.238.9650. The IVR offers information regarding claim status, pending claims, redetermination status, beneficiary eligibility, status for same or similar equipment inquiries, skilled nursing facility/inpatient hospital stay information, hospice information, diabetic supplies, and diabetic shoe claims. If you select #2 for diabetic shoes, the IVR will check for diabetic shoe claims for codes A-5500 and A-5501 that have been billed within the calendar year entered. The IVR will return the Healthcare Common Procedure Coding System (HCPCS) code billed, the date of service billed, the number of services, and the national provider identifier (NPI) of the billing supplier. The IVR will also let you know if the service was not approved for payment. You may also check claims for diabetic shoe inserts (A-5503-A-5508, A-5510, and A-5512-A-5513). To do so, enter the last four digits of the HCPCS code, and the IVR will check for claims with that code that were billed within the calendar year entered. For more information, visit

Lisa Lake-Salmon is the president of Acc-Q-Data, which provides billing, collections, and practice management software. She has been serving the O&P profession for more than a decade. We invite readers to write in and ask any questions they may have regarding billing, collections, or related subjects. While every attempt has been made to ensure accuracy, The O&P EDGE is not responsible for errors. For more information, contact or visit