To determine how anticoagulation services will be paid, one must consider three issues: (1) coverage policy, (2) payment policy, and (3) coding. Coverage policy determines whether anticoagulation services are eligible for payment under the terms of the benefit plan. For public payers (e.g., Medicare and Medicaid), coverage is determined by statute. For private payers, coverage is determined by contract (benefit plan agreements) under requirements set out by state or federal law. Payment policy determines how the allowed payments are determined and what, if any, copayments or coinsurance will apply. Coding is the language providers use to tell payers what they have done and why.* To be eligible for coverage, a service must be included under the scope of benefits and not otherwise excluded. The benefits under most benefit plans are described broadly and include hospital, physician, clinical laboratory, home health, and skilled nursing facility services. The scope of benefits under Medicare is set out in the Social Security Act. Anticoagulation services are not listed specifically under the scope of benefits. Anticoagulation services may include physician services for evaluating a patient on therapy, obtaining blood specimens, and for administration of a low molecular weight heparin; clinical laboratory services for monitoring prothrombin time (PT) levels; hospital services if the patient is evaluated and managed in a hospital setting; skilled nursing facility services if the patient is managed in that setting; and home health agency services if the patient is managed at home. Home prothrombin time (PT) monitors meet the criteria for durable medical equipment (DME), a separately listed item under the scope of benefits. Some, but not all, benefit plans include outpatient prescription drugs. Medicare does not cover outpatient prescription drugs generally. Coverage under Medicare is limited to drugs that are not usually self-administered by the patient. Therefore, a drug like warfarin is not covered under Medicare because it is not included under the scope of benefits. Warfarin may be covered under certain Medicare supplement policies (NAIC standard plans H, I, J). A low molecular weight heparin (LMWH) may be covered under Medicare when administered by a physician or hospital but would not be covered when selfadministered by a patient. Exclusions may apply two ways: (1) to all beneficiaries at all times (that is, the item or service is never covered) or (2) to specific beneficiaries or under specific circumstances. Some items are specifically excluded (e.g., hearing aids). Anticoagulation services are not specifically excluded. Other items may be excluded because the payer considers the item or service to be investigational or experimental. Under these circumstances, the payer will deny coverage whenever the item or service is ordered. For example, the Medicare Durable Medical Equipment Regional Carriers (DMERCs) have denied coverage for home PT testing because the DMERCs believe that the benefits of home testing have not been proved. CMS’s Coverage and Analysis Group is reviewing the evidence on this issue and is expected to issue a coverage decision allowing coverage in 2001. Items and services that are generally covered also must be considered medically necessary for the specific patient at the specific time. A payer may determine that it is medically necessary to order a PT test every 3 to 4 weeks, for example, but not every 3 to 4 days. The payment policies that apply to covered items and services vary by the setting where the service is provided. Under Medicare, there