M31.11 HSCT-TMA Maps to HCC 454 in V28. M31.10 and M31.19 Map to HCC 112.

If you searched M31.11, HSCT-TMA, or M31.19 next to T86.5, T86.0, or V28, you are looking at a transplant cluster where the M31.1 leaf you pick decides the CMS-HCC V28 category.

The M31.1 heading (Thrombotic microangiopathy) has three billable leaves, and they do not land in the same V28 category. On the live M31.11 card (Hematopoietic stem cell transplantation-associated thrombotic microangiopathy [HSCT-TMA]), CMS-HCC V28 reads HCC 454 (Stem Cell, Including Bone Marrow, Transplant Status/Complications). The live M31.10 card (Thrombotic microangiopathy, unspecified) and M31.19 card (Other thrombotic microangiopathy) read HCC 112 (Immune Thrombocytopenia and Specified Coagulation Defects and Hemorrhagic Conditions).

The live HCC 454 hub shows a source-labeled community non-dual aged reference coefficient of 1.068 and 14 ICD-10-CM codes. M31.11 is the only M31 code on that list. The live HCC 112 hub shows 0.45 and lists M31.10 and M31.19. Those are category references, not member RAF totals.

The M31.11 card also carries a Code first note for the transplant complication and a long organ dysfunction note. Those two notes drive most of the searches that reach this page.

As of October 9, 2026, the public ICD leaf cards default to the FY2027 ICD-10-CM edition and read the V28 result from the CMS 2027 Initial ICD-10-CM Mappings (payment year 2027, 2026 dates of service). For every code in this desk, that card result agrees with the PY2026 V28 CSV and the live HCC 454 and HCC 112 hubs.

This page is the coder-desk walk for transplant-associated thrombotic microangiopathy under CMS-HCC V28.

Desk table: verified maps (2026-10-09)

Coeff refs are the community non-dual aged references shown on the live cards (RAF 1.068 and 0.450) and the hubs (1.068 and 0.45). Not member totals. Segment coefficients vary. HCC 454 sits in no V28 hierarchy: it does not trump another HCC and is not trumped by one. HCC 112 is trumped only by HCC 111 (Hemophilia, Male), and it does not trump HCC 454. Two HCC 454 codes in the same year still count as one HCC 454.

The M31.1 and T86.0 headings are nonbillable. Report a leaf. M31.11, T86.5, and the T86.0- leaves take no 7th character.

Sequencing: Code first the transplant complication

The live M31.11 card reads Code first, if applicable: "complications of bone marrow transplant (T86.0-)" and "complications of stem cell transplant (T86.5)". In practice:

1. Transplant complication code first. The live T86.5 card lists "Complications from stem cells from peripheral blood" and "Complications from stem cells from umbilical cord" under the code. For a bone marrow transplant, use a T86.0- leaf. Among those leaves, T86.09 (Other complications of bone marrow transplant) is the one whose title fits a named complication that is not rejection, failure, or infection. Confirm the leaf in the Alphabetic Index and with your policy.

2. Then M31.11. The T80 to T88 section note on the T86 cards says to use "code(s) to identify the specified condition resulting from the complication".

3. Then each documented organ dysfunction. The M31.11 card note reads "code to identify specific organ dysfunction, such as:" and lists acute kidney failure (N17.-), acute respiratory distress syndrome (J80), capillary leak syndrome (I78.8), diffuse alveolar hemorrhage (R04.89), encephalopathy (metabolic) (septic) (G93.41), fluid overload, unspecified (E87.70), graft versus host disease (D89.81-), hemolytic uremic syndrome (D59.3-), hepatic failure (K72.-), hepatic veno-occlusive disease (K76.5), idiopathic interstitial pneumonia (J84.11-), and sinusoidal obstruction syndrome (K76.5).

Code only the organ dysfunction the provider documents, and check each code's own card for its V28 status. This desk verified only N17.9, which shows No V28 HCC for 2026 dates of service. The other codes in that note are not mapped or sequenced here.

What this means for V28

• M31.11 and T86.5 (or a T86.0- leaf) both map to HCC 454. Together they still count as one HCC 454. The T86 code is on the claim because the Code first note asks for it, not to add a category.
• GVHD codes also map to HCC 454. The T86 category note says to code other transplant complications, such as "graft-versus-host disease (D89.81-)", and the D89.81 cards carry Code first "complications of transplanted organs and tissue (T86.-)". A documented D89.81- code with M31.11 does not add a second category.
• M31.10 and M31.19 map to HCC 112, and HCC 112 is not in a hierarchy with HCC 454. If documented HSCT-TMA were coded as M31.19 next to T86.09, the claim would show both HCC 112 and HCC 454. That is a specificity error, not extra capture. When the provider documents TMA associated with the stem cell transplant, the code is M31.11.
• The reverse miss also happens. If the record suggests the TMA is transplant associated but the provider has not documented the link, M31.10 lands in HCC 112. A compliant provider query for the link is the fix, not a code swap. See provider query templates.

M31.19 is where TTP lives

The live M31.19 card lists Thrombotic thrombocytopenic purpura under the code. The D69 category note on the D69.6 card carries Excludes1: thrombotic thrombocytopenic purpura (M31.19). So documented TTP goes to M31.19 (HCC 112), not to D69.6. D69.6 itself shows no V28 HCC.

Status codes are not companions

Z94.81 and Z94.84 also map to HCC 454. The Z94 category on both cards has Excludes1: complications of transplanted organ or tissue - see Alphabetical Index. When the provider documents a transplant complication coded with T86.5 or a T86.0- leaf, do not add the status code for the same transplant. See status Z codes that map.

MEAT for mapped HCC 454

HCC 454 still needs a supported diagnosis in an eligible encounter in the year. A visit note that says "history of TMA" with no current assessment does not support M31.11 by itself.

For M31.11, the note should support:

• M Monitor: blood counts, hemolysis labs, kidney function, or blood pressure trends when documented
• E Evaluate: lab or biopsy results reviewed at the visit, and the provider's link between the TMA and the transplant
• A Assess: an explicit TMA diagnosis tied to the stem cell or bone marrow transplant, with its current status
• T Treat: a medication change, a therapy plan, or a documented follow-up plan for the TMA

MEAT is a review mnemonic, not a universal CMS coding rule. Follow the applicable coding, encounter, program, and payer requirements. See MEAT, acute vs history of, and problem lists.

Audit and query traps

1. Reporting M31.1 or T86.0. Both are nonbillable headings.

2. Coding M31.19 or M31.10 for documented HSCT-TMA. M31.11 is the specific code.

3. Coding M31.11 when the provider has not linked the TMA to the transplant. Query when the record suggests a link.

4. Skipping the Code first T86.5 or T86.0- code when it applies.

5. Expecting T86.5 plus M31.11 plus a D89.81- code to count as more than one HCC 454.

6. Adding Z94.81 or Z94.84 next to a T86 complication code for the same transplant.

7. Leaving documented organ dysfunction off the claim, or adding organ dysfunction the provider did not document.

8. Assuming every organ dysfunction code maps. N17.9 has no V28 HCC. Check each card.

9. Coding documented TTP as D69.6. The D69 Excludes1 note sends TTP to M31.19.

10. Using the 1.068 or 0.450 CNA reference as a member RAF total.

11. Inventing Coding Clinic quotes, competitor CTAs, or PHI examples.

Two-minute check

1. Did the provider document TMA, and did they link it to the stem cell or bone marrow transplant?

2. Linked? Code the transplant complication first: T86.5 for a stem cell transplant, or the right T86.0- leaf for a bone marrow transplant.

3. Add M31.11.

4. Not linked? M31.10, or M31.19 for another specified type such as TTP. Query if the record suggests a link.

5. Add each documented organ dysfunction and check its card for V28 status.

6. No Z94.81 or Z94.84 next to a T86 complication code for the same transplant.

7. Confirm the HCC on the live card and in the V28 CSV. Confirm MEAT for this year.

Related desks and tools

• Live cards: M31.11, M31.10, M31.19, M31.1, T86.5, T86.09, T86.0, D89.811, Z94.84, N17.9
• Hubs: HCC 454, HCC 112
• Lookup: ICD-10 to HCC, Encoder
• Evidence habits: MEAT, acute vs history of, Excludes1 vs Excludes2, provider query templates, hierarchy and trumping
• Nearby desks: T86.41 liver transplant rejection, status Z codes that map, D68.311 acquired hemophilia, HCC 112

Sources

• Live HCC Buddy ICD-10-CM cards (FY2027 Tabular display) and the V28 HCC 454 and HCC 112 hubs, fetched October 9, 2026
• FY2027 ICD-10-CM order file billable flags, on HCC Buddy main
• PY2026 V28 mapping, hierarchy, and relative factor files on HCC Buddy main

V28 mappings come from the cited live code pages and the PY2026 V28 CSV. Coefficients are source-labeled references, not member totals. Not medical advice. Not a Coding Clinic reprint.

Current as of October 9, 2026. Always confirm the PY2026 V28 CSV and the live HCC hub before you lock a map claim.