NCD190.17

 

PROTHROMBIN TIME (PT)

 

Effective Date of this Version

1/1/2003

 

Benefit Category

• Diagnostic Laboratory Tests.

• Note: This may not be an exhaustive list of all applicable Medicare benefit categories for this item or service.

 

Item/Service Description

• Basic plasma coagulation function is readily assessed with a few simple laboratory tests:

o Partial thromboplastin time (PTT).

o PT, thrombin time (TT).

o 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.

o Deficiencies of factors may be related to decreased production or increased consumption of coagulation factors.

o 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).

o The INR is the PT ratio that would result if the WHO reference thromboplastin had been used in performing the test.

• Current medical information does not clarify the role of laboratory PT testing in patients who are self-monitoring.

o Therefore, the indications for testing apply regardless of whether or not the patient is also PT self-testing.

 

Indications and Limitations of Coverage

 

Indications

• A PT may be used to assess patients taking warfarin.

o The prothrombin time is generally not useful in monitoring patients receiving heparin who are not taking warfarin.

• 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; unexplained bruising; abnormal bleeding, hemorrhage or hematoma; petechiae or other signs of thrombocytopenia that could be due to disseminated intravascular coagulation.

• 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.

o Such abnormalities may be genetic or acquired.

 For example:

 Dysfibrinogenemia.

 Afibrinogenemia (complete).

 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.

 Lupus erythematosus; hypercoagulable state.

 Paraproteinemia.

 Lymphoma.

 Amyloidosis.

 Acute leukemias.

 Chronic leukemias.

 Plasma cell dyscrasia.

 HIV infection.

 Malignant neoplasms.

 Hemorrhagic fever.

 Salicylate poisoning.

 Obstructive jaundice.

 Intestinal fistula.

 Malabsorption syndrome.

 Colitis.

 Chronic diarrhea.

 Presence of peripheral venous or arterial thrombosis.

 Pulmonary emboli.

 Myocardial infarction.

 Patients with bleeding or clotting tendencies.

 Organ transplantation.

 Presence of circulating coagulation inhibitors.

• 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.

o 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.

 

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 or renal failure, unspecified.

• The need to repeat this test is determined by changes in the underlying medical condition and/or the dosing of warfarin.

o In a patient on stable warfarin therapy, it is ordinarily not necessary to repeat testing more than every two to three weeks.

o 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.

• 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.

• 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

o There are signs or symptoms of a bleeding.

o Thrombotic abnormality.

o Personal history of bleeding.

o Thrombosis.

o Condition associated with a coagulopathy.

o Hospital/clinic-specific policies, protocols, etc., in and of themselves, CANNOT alone justify coverage.

• Note: Scroll down for links to the quarterly Covered Code Lists (including narrative).

 

Cross Reference

• Also see the Medicare Claims Processing Manual, Chapter 120, Clinical Laboratory Services Based on Negotiated Rulemaking.

 

Coverage Transmittal Link

• http://www.cms.gov/transmittals/downloads/R17ncd.pdf

 

Other

Covered Code Lists (including narrative)

• January 2013

October 2012

July 2012

April 2012

January 2012

October 2011

July 2011

April 2011

January 2011

October 2010

July 2010

April 2010

January 2010

October 2009

July 2009

April 2009

January 2009

October 2008

July 2008

April 2007

January 2007

 

Changes to Lab NCD Edit Software

• January 2012

October 2011

January 2011

October 2010

July 2010

October 2009

July 2009

January 2009

October 2008

July 2008

April 2007

January 2007

October 2006

July 2006

April 2006

January 2006

October 2005

July 2005

April 2005

January 2005

October 2004

July 2004

April 2004

January 2004

October 2003

July 2003

April 2003

 

Coding Analyses for Labs (CALs)

• This NCD has been or is currently being reviewed under the National Coverage Determination process.

• The following are existing associations with CALs, from the Coding Analyses for Labs database.

• Original consideration for Partial Thromboplastin Time (Addition of ICD-9-CM 289.81, Primary Hypercoagulable State as a covered indication) (CAG-00327N)

• Original consideration for Prothrombin Time (Addition of ICD-9-CM 289.81, Primary Hypercoagulable State as a Covered Indication) (CAG-00328N)

• Original consideration for Prothrombin Time (PT) (Addition of ICD-9-CM V58.83, Encounter for therapeutic drug monitoring, as a covered indication) (CAG-00339N)

• Original consideration for Prothrombin Time (PT) (Addition of two ICD-9-CM diagnosis codes) (CAG-00428N)

• Original consideration for Prothrombin Time (PT) and Partial Thromboplastin Time (PTT) tests (Removal of Unspecified Joint Replacements) (CAG-00246N)

• Original consideration for Prothrombin Time (PT) NCD 190.17 (Addition of ICD-9-CM diagnosis code 197.7 Secondary Malignant Neoplasm of Liver) (CAG-00404N)

• Original consideration for Prothrombin Time and Fecal Occult Blood (Revision of ICD-9-CM Codes for Injury to Gastrointestinal Tract) (CAG-00187N)

• Original consideration for Prothrombin Time and Partial Thromboplastin Time (Revision of ICD-9-CM Codes for Pre-operative Examinations) (CAG-00184N)

• Original consideration for Prothrombin Time and Partial Thromboplastin Time (Revision of ICD-9-CM Codes for Swelling of Limb) (CAG-00201N)

 

Medicare NCD Link