Key facts for NCD 20.30
- Benefit category
- Diagnostic Tests (other)
- Effective date
- 01/13/2015
- Implemented 06/23/2015
- Transmittal
- Transmittal 182
- Versions published
- 3
- Manual chapter
- 20
- NCD Manual (Pub. 100-03)
TL;DR
NCD 20.30 sets Medicare's national policy for microvolt t-wave alternans (mtwa) under the benefit category "Diagnostic Tests (other)", effective 01/13/2015 and implemented 06/23/2015. Effective for dates of service on and after March 21, 2006, MTWA diagnostic testing is covered for the evaluation of patients at risk for SCD, only when the SA method is used. It has been revised 2 times since publication and binds every Medicare Administrative Contractor nationally.
Item or service described
A. General
Microvolt T-wave Alternans (MTWA) testing is a non-invasive diagnostic test that detects minute electrical activity in a portion of the electrocardiogram (ECG) known as the T-wave. MTWA testing has a role in the stratification of patients who may be at risk for sudden cardiac death (SCD) from ventricular arrhythmias.
Within patient groups that may be considered candidates for implantable cardioverter defibrillator (ICD) therapy, a negative MTWA test may be useful in identifying low-risk patients who are unlikely to benefit from, and who may experience worse outcomes from, ICD placement.
Spectral analysis (SA) is a sensitive mathematical method of measuring and comparing time and the ECG signals. It requires specialized propriety electrodes to calculate minute T-wave voltage changes. Software then analyzes these microvolt changes and produces a report to be interpreted by a physician. The Modified Moving Average (MMA) method uses a temporal domain in which T-wave alternans are assessed as a continuous variable along the complete ECG. The MMA method of MTWA testing is performed using standard ambulatory ECG equipment.
Indications and limitations of coverage
B. Nationally Covered Indications
Effective for dates of service on and after March 21, 2006, MTWA diagnostic testing is covered for the evaluation of patients at risk for SCD, only when the SA method is used.
C. Nationally Non-Covered Indications
N/A
D. Other
Effective for dates of service on and after January 21, 2015, Medicare Administrative Contractors (MACs) acting within their respective jurisdictions may determine coverage of MTWA diagnostic testing for the evaluation of patients at risk for SCD using all other methods.
(This NCD last reviewed January 2015.)
Text reproduced from the CMS Medicare Coverage Database record for NCD 20.30 version 3. View the original on cms.gov.
Revision history
08/2026 - Transmittal 13903 issued August 07, 2026, is being rescinded and replaced by Transmittal 13923, dated August 14, 2026, to update NCD 20.4 Implantable Cardioverter Defibrillator (ICD) to include additional business requirements for Place of Service (POS) and Claim Adjustment Reason Code (CARC) and Remittance Advice Remark Code (RARC) messages. All other information remains the same. ( TN 13923 ) (CR14570)
08/2026 - The purpose of this Change Request (CR) is to provide a quarterly maintenance update of ICD-10 coding conversions and other coding updates specific to National Coverage Determinations (NCDs). No policy is being changed as a result of these updates. ( TN 13903 ) (CR14570)
01/2024 - Transmittal 12318 issued October 19, 2023, is being rescinded and replaced by Transmittal 12441, dated January 3, 2024, to add FISS to BR 13390.11 and to add clarifying verbiage to business requirement 13390.12. All other information remains the same. ( TN 12441 ) (CR13390)
10/2023 - The purpose of this Change Request (CR) is to provide a quarterly maintenance update of ICD-10 coding conversions and other coding updates specific to National Coverage Determinations (NCDs). No policy is being changed as a result of these updates. ( TN 12318 ) (CR13390)
08/2022 - Transmittal 11545 dated August 5, 2022, is being rescinded and replaced by Transmittal 11584, dated, August 31, 2022. ( TN 11584 ) (CR12822)
08/2022 - The purpose of this Change Request (CR) is to provide a maintenance update of ICD-10 conversions and other coding updates to specific NCDs. ( TN 11545 ) (CR12822)
01/2018 - This Change Request (CR) constitutes a maintenance update of International Code of Diseases, Tenth Revision (ICD-10) conversions and other coding updates specific to National Coverage Determinations (NCDs). These NCD coding changes are the result of newly available codes, coding revisions to NCDs released separately, or coding feedback received.
Previous NCD coding changes appear in ICD-10 quarterly updates that can be found at: https://www.cms.gov/Medicare/Coverage/CoverageGenInfo/ICD10.html , along with other CRs implementing new policy NCDs. Edits to ICD-10 and other coding updates specific to NCDs will be included in subsequent quarterly releases and individual CRs as appropriate. No policy-related changes are included with the ICD-10 quarterly updates. Any policy-related changes to NCDs continue to be implemented via the current, long-standing NCD process. ( TN 2005 ) (CR10318)
11/2017 - This Change Request (CR) constitutes a maintenance update of International Code of Diseases, Tenth Revision (ICD-10) conversions and other coding updates specific to National Coverage Determinations (NCDs). These NCD coding changes are the result of newly available codes, coding revisions to NCDs released separately, or coding feedback received. ( TN 1975 ) (CR10318)
05/2015 - Effective January 13, 2015, CMS decided that no national coverage determination (NCD) is appropriate at this time for for microvolt t-wave alternans (MTWA) testing using the modified moving average (MMA) method for the evaluation of patients at risk for sudden cardiac death (SCD). Implementation date: 06/23/2015 Effective date: 01/13/2015 ( TN 182 )(CR9162)
03/2013 - CMS translated the information for this policy from ICD-9-CM/PCS to ICD-10-CM/PCS according to HIPAA standard medical data code set requirements and updated any necessary and related coding infrastructure. These updates do not expand, restrict, or alter existing coverage policy. Implementation date: 10/07/2013 Effective date: 10/1/2015. ( TN 1199 ) ( TN 1199 ) (CR 8197)
07/2008 - Effective Date: 05/12/2008. Implementation Date: 08/25/2008. ( TN 88 ) (CR6154)
03/2006 - Effective Date: 03/21/2006. Implementation Date: 04/03/2006. ( TN 49 ) (CR4351)
How this NCD shows up on remittances
A service denied under a National Coverage Determination returns CARC 50 (not deemed medically necessary) with remark N386 (decision based on an NCD); a denial citing a local policy instead carries N115. Because NCDs bind nationally, the appeal path is documentation that the patient meets the indications above, not a contractor-policy argument.
How QuickIntell applies NCD 20.30
QuickAuth checks the ordered service and diagnosis against NCD and LCD criteria before the encounter, QuickCode validates the diagnosis pairing on the claim, and QuickRCM routes CARC 50 denials with the policy text and the covered-code list attached so the appeal starts with evidence.
Frequently asked questions — NCD 20.30
What does NCD 20.30 cover?
Effective for dates of service on and after March 21, 2006, MTWA diagnostic testing is covered for the evaluation of patients at risk for SCD, only when the SA method is used. The full indications and limitations are reproduced on this page from the CMS Medicare Coverage Database.
When did NCD 20.30 take effect?
The current version (3) is effective 01/13/2015, implemented 06/23/2015, published in transmittal 182. CMS lists 3 versions of this NCD.
Does a Local Coverage Determination override NCD 20.30?
No. A National Coverage Determination binds all Medicare Administrative Contractors; an LCD can only address services or circumstances the NCD leaves open. Claims denied under this NCD typically return CARC 50 with remark N386 (NCD) rather than N115 (LCD).
Sources
Every figure on this page is taken from the CMS publications below, as released by the Centers for Medicare & Medicaid Services. Projection built 2026-10-02. Verify against the primary file before billing or contracting decisions.
- Medicare Coverage Database NCDs via the CMS Coverage APIVersion API snapshot 2026-09-27 · effective 2026-09-20 · file national-coverage-ncd.jsonSHA-256 a90fadfd264b9ef4…
Disclaimer
This page reproduces the CMS National Coverage Determination text and, for laboratory NCDs, the CMS ICD-10 edit lists, as an operational reference. Coverage decisions depend on the full policy, the claim and the contractor; nothing here is legal, clinical or billing advice. CPT codes are shown as numbers only; CPT descriptors are copyright AMA.