Oncology & Hematology Coding Alert

Cancer patients occasionally are at risk of developing blood clots, requiring the administration of anticoagulation medication. Prothrombin time (85610) is one way to measure the effectiveness of the medication, yet oncology practices often fail to convey that need and thereby risk claim denials and lost reimbursement. Documenting medical necessity for a prothrombin time (PT) study will ensure proper payment.

When trying to prove medical necessity for a prothrombin time test, concentrate on pre-existing conditions and residual diseases, says Laurie Castillo, MA, CPC, president of Physician Coding and Compliance Consulting and the American Academy of Procedural Coders Virginia chapter, both in Manassas, Va.

For instance, breast cancer is not a billable reason for prothrombin time, says Elaine Towle, CMPE, practice administrator for New Hampshire Oncology and Hematology, an oncology practice in Hooksett, N.H. The big issue is that Medicare requires a billable diagnosis, but the disease is not a billable diagnosis.

Youre not doing the test because of the cancer, notes Castillo. Youre doing the test because of a residual disease that might be caused by the cancer. Thats what you need to concentrate on.

Castillo adds that pre-existing conditions such as heart disease, when a patient is on Coumadin also may warrant the test, which allows physicians to monitor blood coagulation to determine future cancer treatment.

Documenting the appropriate diagnosis code is the key to avoiding a claim denial. The appropriate code must be submitted with each claim, and documentation requirements must be contained in the patients medical record and be available to the Medicare intermediary upon request.

Understand Coagulation-measuring Tests

When billing for PT, it is important to know and understand the tests that measure coagulation. In addition to PT, plasma coagulation function is also accessed with partial thromboplastin time (PTT), 85730; thrombin time (TT), 85670; or a quantitative fibrin degradation determination, 85379.

The PT test is an in-vitro laboratory test used to assess coagulation and the extrinsic or tissue factor dependent pathway. Although similar to the PT, the PTT test assesses the intrinsic limb of the coagulation system. Both tests evaluate the common coagulation pathway involving all the reactions that occur after the activation of factor X, a plasma protein critical to normal clotting. The TT and quantitative fibrinogen determination measure fibinogen concentration.

Although a prothrombin test most commonly is used to measure the effect of warfarin (Coumadin) and regulate its dosing, it also is used to evaluate:

The extrinsic coagulation system;
Dysfibrinogenemia;
Afibrinogenemia (complete);
Heparin, coumarin, or warfarin effect/therapy;
Liver failure;
Disseminated intravascular coagulation (DIC);
Congenital deficiencies of factors II, V, VII, X;
Prothrombin deficiency; and
Vitamin K deficiency.

PT is expressed either in seconds and/or as an international normalized ratio (INR). The INR is the PT ratio that would result if the World Health Organization reference thromboplastin is used in performing the test. Because INR is a calculation, it usually is not paid separately from or in addition to the PT, but is considered part of the conventional PT.

Document Medical Necessity With ICD-9-CM Codes

Getting paid for prothrombin tests is simply a matter of documenting medical necessity, says Towle. Oncology practices need to be cognizant of the ICD-9 codes that are acceptable diagnoses to prove medical necessity. Payment denials usually are attributed to documenting an improper ICD-9 code or failing to list one at all, she says. Assuming that a cancer diagnosis is sufficient to justify the administration of prothrombin time will result in denied payment.

Usually the [prothrombin time test] is monitored because of another medical condition things like atrial fibrillation and other cardiac conditions, adds Towle. Frequently we see patients with some sort of thrombosis or clot and use a diagnosis in the 453.0-453.9 range, but we could use almost any of the diagnoses on the list, depending on the patient.

Editors note: Prothrombin time diagnosis codes are listed in the enclosed insert. But coders should avoid using an accepted diagnosis code just to ensure payment. Chart documentation must support the ICD-9 coding to avoid trouble during audits.