In Memoriam: Gregory B. Root
National Coverage Determination
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Prothrombin Time (PT)
CMS Policy Number: 190.17
Description: Basic plasma coagulation function is readily assessed with a few simple laboratory tests: the Partial Thromboplastin Time (PTT), Prothrombin Time (PT), Thrombin Time (TT), or a quantitative fibrinogen determination. The PT test is one in-vitro laboratory test used to assess coagulation. While the PTT assesses the intrinsic limb of the coagulation system, the PT assesses the extrinsic or tissue factor dependent pathway. Both tests also evaluate the common coagulation pathway involving all the reactions that occur after the activation of factor X. Extrinsic pathway factors are produced in the liver and their production is dependent on adequate vitamin K activity. Deficiencies of factors may be related to decreased production or increased consumption of coagulation factors. The PT/INR is most commonly used to measure the effect of warfarin and regulate its dosing. Warfarin blocks the effect of vitamin K on hepatic production of extrinsic pathway factors.
A PT is expressed in seconds and/or as an international normalized ratio (INR). The INR is the PT ratio that would result if the WHO reference thromboplastin was used in performing the test.
Current medical information does not clarify the role of laboratory PT testing in patients who are self monitoring. Therefore, the indications for testing apply regardless of whether or not the patient is also PT self-testing.
1. A PT may be used to assess patients taking warfarin. The PT is generally not useful in monitoring patients receiving heparin who are not taking warfarin.
2. A PT may be used to assess patients with signs or symptoms of abnormal bleeding or thrombosis. For example: Swollen extremity with or without prior trauma
Abnormal bleeding, hemorrhage or hematoma
Petechiae or other signs of thrombocytopenia that could be due to Disseminated Intravascular Coagulation
3. A PT may be useful in evaluating patients who have a history of a condition known to be associated with the risk of bleeding or thrombosis that is related to the extrinsic coagulation pathway. Such abnormalities may be genetic or acquired. For example: Dysfibrinogenemia
Acute or chronic liver dysfunction or failure, including Wilson’s disease and Hemochromatosis
Disseminated intravascular coagulation (DIC)
Congenital and acquired deficiencies of factors II, V, VII, X
Vitamin K deficiency
Acute and chronic leukemias
Plasma cell dyscrasia
Presence of peripheral venous or arterial thrombosis or pulmonary emboli or myocardial infarction
Patients with bleeding or clotting tendencies
Presence of circulating coagulation inhibitors
4. A PT may be used to assess the risk of hemorrhage or thrombosis in patients who are going to have a medical intervention known to be associated with increased risk of bleeding or thrombosis. For example: Evaluation prior to invasive procedures or operations of patients with personal history of bleeding or a condition associated with coagulopathy.
Prior to the use of thrombolytic medication
1. When an ESRD patient is tested for PT, testing more frequently than weekly requires documentation of medical necessity, e.g., other than chronic renal failure or renal failure unspecified.
2. The need to repeat this test is determined by changes in the underlying medical condition and/or the dosing of warfarin. In a patient on stable warfarin therapy, it is ordinarily not necessary to repeat testing more than every two to three weeks. When testing is performed to evaluate a patient with signs or symptoms of abnormal bleeding or thrombosis and the initial test result is normal, it is ordinarily not necessary to repeat testing unless there is a change in the patient’s medical status.
3. Since the INR is a calculation, it will not be paid in addition to the PT when expressed in seconds, and is considered part of the conventional PT test.
4. Testing prior to any medical intervention associated with a risk of bleeding and thrombosis (other than thrombolytic therapy) will generally be considered medically necessary only where there are signs or symptoms of a bleeding or thrombotic abnormality or a personal history of bleeding, thrombosis or a condition associated with a coagulopathy. Hospital/clinic-specific policies, protocols, etc., in and of themselves, cannot alone justify coverage.
Frequency Limitations: When an ESRD patient is tested for PT, testing more frequently than weekly requires documentation of medical necessity [e.g. other than Chronic Renal Failure (ICD-9-CM 585) or Renal Failure, Unspecified (ICD-9-CM 586)].
The need to repeat this test is determined by changes in the underlying medical condition and/or the dosing of warfarin. In a patient on stable warfarin therapy, it is ordinarily not necessary to repeat testing more than every two to three weeks.
To review all requirements of this policy, please see:
CMS NCD listing by Chapter
Covered ICD-10 Codes.
.... and many more.
|A01.00||Typhoid fever, unspecified|
|A01.02||Typhoid fever with heart involvement|
|A01.09||Typhoid fever with other complications|
|A01.1||Paratyphoid fever A|
|A01.2||Paratyphoid fever B|
|A01.3||Paratyphoid fever C|
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