Where this LCD applies
Each contract number is a jurisdiction on the remittance; the policy binds claims processed under these contracts and no others.
Billing and coding: diagnoses and procedure codes
Since 2019 the codes live in the companion article rather than the LCD. Billing and Coding A57661 (Billing and Coding: MDS FISH) carries the diagnosis and procedure lists the contractor loads as the claims edit. CPT codes are shown as bare numbers because the descriptors are licensed by the AMA; HCPCS Level II descriptors are public and shown.
A57661: Billing and Coding: MDS FISH (Billing and Coding, effective 2025-10-23)
- Covered ICD-10-CM codes
- 10
- 1 group
- Non-covered ICD-10-CM codes
- 0
- Procedure codes listed
- 5
- Full article
- cms.gov record
| ICD-10-CM | Description (FY2027) |
|---|---|
| C94.6 | — |
| D46.0 | — |
| D46.1 | — |
| D46.20 | — |
| D46.21 | — |
| D46.22 | — |
| D46.A | — |
| D46.B | — |
| D46.C | — |
| D46.Z | — |
Procedure codes: 88271, 88273, 88274, 88275, 88291.
Coverage indications, limitations and medical necessity
This policy provides coverage for indicated fluorescent in situ hybridization (FISH) probes for patients whose bone marrow examination is suggestive of myelodysplasia (MDS) and who have an inadequate cytogenetic assessment by conventional karyotyping. In general, conventional karyotype analysis is sufficient for confirmation for the diagnosis of MDS. MDS FISH studies should only be performed when there are fewer than 20 metaphases available for analysis, or an unresolved karyotype. Medicare will only cover up to 4 FISH studies (-7 or del(7q), -5 or del(5q), +8 and del(20q)) on initial evaluation to diagnose MDS. Reflex testing for additional FISH markers to diagnose MDS is only reasonable and necessary when the initial 4 studies are negative, or the diagnosis remains uncertain following the initial 4 probes.
Generally, FISH testing is not reasonable and necessary for diagnosing MDS and provides little if any additional information to conventional karyotyping.
Summary of evidence (opening)
The myelodysplastic syndromes (MDS) represent a spectrum of clonal bone marrow diseases with heterogeneous presentations. The classic triad for MDS includes 1 or more cytopenias, defective differentiation (dysplasia) of 1 or more blood cell lines and marrow hypercellularity. Over time, there is an increased rate of progression to acute myeloid leukemia (AML). These secondary AML cases carry a worse prognosis than de novo AML cases. Furthermore, there are myeloid neoplasms that share overlapping characteristics with both MDS and myeloproliferative neoplasms (MPNs), such as chronic myelomonocytic leukemia (CMML). The World Health Organization (WHO) has designated these diseases separately as MDS/MPNs, distinct from either MDS or MPNs. (1)
According to the 2016 National Comprehensive Cancer Network (NCCN) Guidelines, the overall incidence of MDS is approximately 5/100,000 per year, primarily in adults. MDS is rare in patients under the age of 40, but much more common in older patients. The incidence of MDS among patients 70-79 years of age is 30/100,000, and in patients > 80 years the incidence is 60/100,000. (2)
MDS has historically been classified by a combination of traditional laboratory techniques, such as demonstration of stable cytopenias by complete blood count, microscopic examination of a bone marrow biopsy, and bone marrow cytogenetic (conventional karyotype) studies. Other than the clinical feature of the number of cytopenias and specific cytogenetic changes found recurrently in MDS, all other diagnostic criteria in MDS rely upon light microscopy findings. These include the dysplastic changes on 1 or more cell lineages of megakaryocytes, erythrocytes and granulocytes; increased myeloblasts; and/or presence of ringed sideroblasts. Low-risk MDS is associated with dysplasia affecting only 1 cell lineage, with or without ringed sideroblasts, and isolated deletions involving the long arm of chromosome 5 (5q-). High-risk disease is associated with dysplasia across multiple lineages, increased blast percentages, and complex karyotype.
Neither the 2016 WHO Classification of MDS, the International Prognostic Scoring System (IPSS) nor the Revised IPSS (IPSS-R) require the use of additional MDS-associated mutations to establish a diagnosis of MDS. As noted in NCCN 2017 Guidelines, “Bone marrow or peripheral blood cells may be assayed for MDS-associated gene mutations. These can establish the presence of clonal hematopoiesis which can help exclude benign causes of cytopenia with non-diagnostic morphology but do not establish the diagnosis of MDS in the absence of clinical diagnostic criteria.”
The contractor cites 8 sources in the bibliography; the full summary and analysis of evidence are in the CMS record.
Dates, lineage and related policies
- Original determination effective
- 2019-06-03
- Current revision effective
- 2025-10-23
- Last reviewed by the contractor
- 2022-05-09
- MCD version
- 16
Other related documents: A56446 (Response to Comments), A56447 (Response to Comments).
Using this policy on a claim
Match the documented indication to the covered indications above before the service is scheduled, carry a diagnosis from the article's covered list on the claim line, and keep the elements the documentation section asks for in the record, because the contractor can request it later through medical review. A denial under this policy arrives as CARC 50 with remark N115; the LCD lookup guide walks through the appeal path and the Advance Beneficiary Notice rules, and the Noridian Healthcare Solutions, LLC hub lists every other active policy from the same contractor.
The same policy title at other contractors
Contractors often adopt each other's policies and then revise them separately, so the criteria and the diagnosis lists drift apart. The topic comparison lines up every version.
Frequently asked questions
What does LCD L37620 cover?
This policy provides coverage for indicated fluorescent in situ hybridization (FISH) probes for patients whose bone marrow examination is suggestive of myelodysplasia (MDS) and who have an inadequate cytogenetic assessment by conventional karyotyping. In general, conventional karyotype analysis is sufficient for confirmation for the diagnosis of MDS. MDS FISH studies should only be performed when there are fewer… The full indications and limitations are reproduced on this page from the CMS Medicare Coverage Database export of September 24, 2026.
Which states does LCD L37620 apply to?
Noridian Healthcare Solutions, LLC applies it to Medicare claims in AK, AS, AZ, CA, CNMI, GU, HI, ID, MT, ND, NF, NV, OR, SD, SF, UT, WA, WY. A Local Coverage Determination binds only the contractor that wrote it; the same service in another jurisdiction is judged under that contractor's own policy or, where none exists, claim by claim.
Which diagnosis codes support medical necessity under LCD L37620?
The companion billing and coding article A57661 lists 10 ICD-10-CM codes in 1 group that support medical necessity; the first 10 appear on this page and the complete list is in the article on cms.gov.
How do I appeal a denial under LCD L37620?
The remittance carries claim adjustment reason code 50 with remark code N115, naming the LCD. Compare the documented indication with the policy's covered indications and the article's diagnosis list, then file a redetermination within 120 days with the record attached; if the service genuinely falls outside the policy, the patient can be billed only when a valid Advance Beneficiary Notice was obtained before the service.
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, current LCD exportVersion MCD release 2026-09-24 · effective 2026-09-20 · file lcd.csvSHA-256 2fcc4251b6ddd1eb…
- Medicare Coverage Database, current Billing and Coding Articles exportVersion MCD release 2026-09-24 · effective 2026-09-20 · file article.csvSHA-256 f31932f1df3b4035…
- ICD-10-CM FY2027 code descriptionsVersion FY2027 · effective 2026-10-01 · file icd10cm_codes_2027.txtSHA-256 3c0583a38ee0e848…
Disclaimer
The policy text and code lists are reproduced from the CMS Medicare Coverage Database export as an operational reference. Verify against the current LCD and article on cms.gov before billing; coverage depends on the full record and the contractor. Not legal, clinical or billing advice.