This coding analysis does not constitute a national coverage determination (NCD). It states the intent of the Centers for Medicare & Medicaid Services (CMS) to issue a change to the list of ICD-9-CM Codes Covered that are linked to the one of the negotiated laboratory NCDs. This decision will be announced in an upcoming recurring update notification in accordance with CMS Pub 100-4, Chapter 16, section 120.2 and will become effective as of the date listed in the transmittal that announces the revision.
To: Administrative File: CAG-00201N
Prothrombin Time and Partial Thromboplastin Time (Revision of ICD-9-CM Codes for Swelling of Limb)
From: Steve E. Phurrough, MD, MPA
Director, Coverage and Analysis Group
Jesse M. Polansky, MD, MPH
Director, Division of Items and Devices
Technical Advisor, Division of Items and Devices
Subject: Coding Analyses for Prothrombin Time and Partial Thromboplastin Time Tests
Date: June 18, 2004
CMS has determined that ICD-9-CM code 729.81, swelling of limb, flows from the existing narrative for conditions for which prothrombin time (PT) and partial thromboplastin time (PTT) tests are reasonable and necessary. We intend to modify the list of "ICD-9-CM Codes Covered by Medicare" in the NCD for PT and PTT to include this code.
On August 15, 2003 CMS began a coding analyses for expansion of ICD-9-CM covered codes list for the PT and PTT NCDs. Basic plasma coagulation function is readily assessed with a few simple laboratory tests: the PTT, PT, thrombin time or a quantitative fibrinogen determination. 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.
III. History of Medicare Coverage
In accordance with section 4554 of the Balanced Budget Act of 1997, CMS entered into negotiations with the laboratory community regarding coverage and administrative policies for clinical diagnostic laboratory services. As part of these negotiations, we promulgated a rule that included 23 NCDs. These NCDs included the PT and PTT tests. The rule was proposed in the March 10, 2000 edition of the Federal Register (65 FR 13082) and was made final on November 23, 2001 (66 FR 58788). The final rule called for a 12-month delay in effectuating the NCDs in accordance with the recommendations of the negotiating committee. Thus, the NCDs became effective on November 25, 2002.
In the laboratory NCDs, CMS determined that coverage of specific tests were reasonable and necessary for certain medical indications. These decisions were evidence-based, relying on scientific literature reviewed by the negotiating committee. The NCDs contain a narrative describing the indications for which the test is reasonable and necessary. We also developed a list of ICD-9-CM codes that designate diagnoses/conditions that fit within the narrative description of indications that support the medical necessity of the test. This list is entitled "ICD-9-CM Codes Covered by Medicare," and includes codes where there is a presumption of medical necessity.
In addition, we developed two other ICD-9-CM code lists. The second list is entitled "ICD-9-CM Codes Denied," and lists diagnosis codes that are never covered by Medicare. The third list is entitled "ICD-9-CM Codes that do not Support Medical Necessity," and includes codes that generally are not considered to support a decision that the test is reasonable and necessary, but for which there are limited exceptions. Tests in this third category may be covered when they are accompanied by additional documentation that supports a determination of reasonable and necessary. We determined in the PT and PTT NCDs that any ICD-9-CM code not listed in either of the ICD-9-CM covered or not covered sections would be categorized into this group that does not support medical necessity.
IV. Timeline of Recent Activities
On March 10, 2000, CMS published a Notice of Proposed Rulemaking (NRPM) in the Federal Register (65 FR 13082). As an addendum to this NPRM, we proposed the 23 NCDs as negotiated by the rulemaking committee for public comment. On November 23, 2001, we published a final rule for coverage and administrative policies for clinical diagnostic laboratory services (66 FR 58788).
On July 29, 2003, Linda Minor of Brookings Hospital made a formal request for reconsideration of the PT and PTT NCDs to include ICD-9-CM code 729.81, swelling of limb, in the list of "ICD-9-CM Codes Covered by Medicare." She stated that the narrative indications for both tests included mentioned swollen extremity with or without prior trauma as a sign or symptom of abnormal bleeding or thrombosis. Thus, she believed the code 729.81 flowed from the narrative indications for PT and PTT and should be added to the list of ICD-9-CM codes covered for that service.
On August 15, 2003 we announced in a tracking sheet posted on the Medicare coverage Internet site (http://cms.hhs.gov/ncdr/trackingsheet.asp?id=103) that we were considering adding the code 729.81, swelling of limb, to the list of covered codes for PT and PTT tests and solicited public comments during a 30-day period. At the end of the public comment period, September 14, 2004, we had not received any comments.
V. General Methodological Principles
During the negotiation meetings that led to the development of the 23 clinical diagnostic laboratory NCDs, we stated our intent that the narrative of the NCDs reflect the substance of the determinations. The addition of the coding lists was intended as a convenience to the laboratories and as a means of ensuring consistency among the Medicare claims processing contractors as they interpreted the narrative conditions that support coverage.
We reiterated this position in the November 23, 2001 final rule (66 FR 58795) in responding to public comments requesting the addition of numerous codes to the NCDs. That is, we stated that:
"It is critical that the narrative indications for the proposed policy and the ICD-9-CM codes that support medical necessity be consistent. Thus, in order for us to add codes to the list of ICD-9-CM codes that support medical necessity, those codes must either be determined to be an appropriate translation of an existing indication, or we must add a new indication for the test in the policy narrative."
Further, in Program Memorandum AB 02-110 we stated our intent as follows:
"The codes included in the NCDs are intended to flow exclusively from the narrative of the NCDs. Therefore, requests for the addition of primary diagnosis codes must include rationale demonstrating the provision of the narrative that supports the inclusion of the code or scientific evidence supporting the inclusion of the condition to the narrative portion of the NCD. Clerical maintenance of the coding lists will be made without following the NCD process. Clerical maintenance may include such actions as revision of codes to be consistent with the annual CPT and ICD-9-CM coding updates, expansion of codes to full range of digits, and correction of code errors that may exist."
VI. CMS Analysis
As noted above, we have taken the position that the "ICD-9-CM Codes Covered by Medicare" list is intended to contain only those codes that flow from the narrative of the indication in the NCD. The PT NCD lists the following as an indication for testing:
"2. A PT may be used to assess patients with signs or symptoms of abnormal bleeding or thrombosis. For example:
a. Swollen extremity with or without prior trauma…."
The PTT NCD includes nearly identical language as follows:
"2. A PTT may be used to assess patients with signs or symptoms of hemorrhage or thrombosis. For example:
b. Swollen extremity with or without trauma."
We believe that the ICD-9-CM code for swelling of limb, 729.81, flows from the existing narrative indications statement that includes swollen extremities. Consequently, we intend to issue a recurring update to the edit module implementing the NCDs to add ICD-9-CM code 729.81 to the list of the ICD-9-CM codes covered for PT and PTT tests.