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D51.2 ICD-10-CM Code: Transcobalamin II deficiency

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Billing Status: YES. This is a valid, specific, and billable ICD-10-CM reference.

Coding at a Glance

Tabular directives
1 Excludes2

Billable · FY2027A valid, specific ICD-10-CM code, reportable for dates of service in FY2027.

What you need to know

Source: CMS/NCHS Official ICD-10-CM tabular notes, quoted. From the CMS/NCHS tabular list for the release in force. A note the category or block publishes applies to this code too; the Instructions section marks which is which.

Excludes2Not included here; may be reported together
  • deficiency of other B group vitamins (E53-)

Most relevant related codes MedCoder-derived

Read off the official notes above and this code’s own position in the tabular list. Which to report is a documentation question; Compare shows the two side by side.

CompareCheck ClaimView Related Codes

Inpatient Payment Groups (MS-DRG)

Potential MS-DRG participation — not a DRG assignment.

MS-DRGs this diagnosis helps define, as principal or secondary, per the CMS ICD-10-CM/PCS MS-DRG Definitions Manual v44, Appendix B.

  • MS-DRG 811 — RED BLOOD CELL DISORDERS WITH MCC (MDC 16)
  • MS-DRG 812 — RED BLOOD CELL DISORDERS WITHOUT MCC (MDC 16)

A diagnosis appearing in a group's logic does not by itself determine the DRG assigned to a stay; the grouper uses the full claim.

Coding instructions

Official Tabular Instructional Notes: the inclusion, exclusion and sequencing notes published for D51.2 in the official ICD-10-CM tabular list, quoted as published.

Source: CMS/CDC — ICD-10-CM Tabular ListRelease: FY2027Effective: October 1, 2026

Trace:FY2027 changesChange historyRelease, file and checksum

Notes without a marker are published on D51.2 itself; “inherited from” names the category or block whose note applies here.

Excludes2 — Not Included Here

Conditions not covered by this code, but which may be reported alongside it when both are present.

Source: inherited from D51

Coder workflow for D51.2

MedCoder structured workflow — derived from this code’s own official record

Documentation check

The provider’s diagnostic statement
Codes are assigned from the provider’s documented diagnosis, not from clinical criteria, test values or a medication list (Guidelines I.A.19).

Official instructions as workflow

  • Excludes2 — not part of D51.2(1 note)

    Coding workflow: The conditions named in this note are not included in D51.2. When the record documents both, both may be reported; the note is a boundary, not a prohibition.

    CompareE53

    See the official tabular notes · Guidelines I.A.12.b

Every row is derived from this code’s own record — its title, tabular notes, 7th-character family and same-category siblings — with fixed MedCoder wording; nothing is inferred about a patient. The official notes and guideline text are in the sections each row links to, and they control.

Don’t confuse D51.2 with…

MedCoder analysis — pairs from this code’s official notes, distinctions written by MedCoder

The codes most likely to be picked instead of D51.2 — named in its own official notes, or sharing its laterality or encounter family — with what separates them and which documentation moves the case. Each links to the full comparison.

  • D51.9— Specificity relationship (Review)

    Overlapping diagnoses in the same category.

    Overlapping codes in the same category — the documentation decides which is the more specific fit.

    What moves you there: A record that documents no more than “Vitamin B12 deficiency anemia, unspecified” takes D51.9; specificity in the record moves it back here.

    Full comparison: D51.2 vs D51.9 →

  • E53— Excludes2 relationship (Informational)

    Distinct conditions — both may be reported.

    A distinct condition — both may be reported when both are documented.

    What moves you there: Documentation of deficiency of other B group vitamins adds E53; it is not part of this code and both may be reported when both are documented.

    Full comparison: D51.2 vs E53 →

Relationships are read from this code's own official notes, its laterality siblings and its encounter family; the wording of each distinction is MedCoder editorial, and the documentation named in each “what moves you there” line is the official note phrase or sibling title itself. Source: CMS ICD-10-CM tabular instructional notes; ICD-10-CM Official Guidelines, Section I.A.12.a.

Coding context

Guidelines, coding notes, decision aids, relationships (with MS-DRG and CCSR classification), hierarchy, HCC, coverage and the context map: what a coder reaches for after the core. Each section names whether it is official source data, a MedCoder-derived relationship or MedCoder editorial.

Code Overview

Transcobalamin II deficiency is a billable ICD-10-CM diagnosis code (D51.2).

MedCoder summary Summary composed by MedCoder from this code's official ICD-10-CM record. The tabular instructional notes themselves appear verbatim below.

Official Coding Guidelines

No excerpt in the ICD-10-CM Official Guidelines names this code specifically. Its chapter carries only this chapter-wide note:

Chapter 3: Disease of the blood and blood-forming organs and certain disorders involving the immune mechanism (D50-D89)

Reserved for future guideline expansion

Verify Before Coding

  • No Medicare Code Editor or MS-DRG Definitions Manual restrictions apply to this code.

From the code registry, the Medicare Code Editor, and the MS-DRG Definitions Manual. Check it against a full claim in Claim Check.

Relationships & Classification

MedCoder-derived relationships — computed from published CMS and AHRQ datasets

Other codes that name D51.2 or its code family, from the CMS ICD-10-CM tabular instructional notes. Tabular-note edges are stored at the code family level that carries each note.

Referenced by 2 Excludes1 notes across 2 chapters: E72.1 — Disorders of sulfur-bearing amino-acid metabolism, R71 — Abnormality of red blood cells (via D51.-).

These codes’ tabular lists mark this diagnosis as mutually exclusive — not reported together unless the conditions are documented as unrelated.

Referenced by 23 Excludes2 notes: E40 — Kwashiorkor (via D51.-), E40-E46 — Malnutrition (E40-E46) (via D51.-), E41 — Nutritional marasmus (via D51.-), E42 — Marasmic kwashiorkor (via D51.-), E43 — Unspecified severe protein-calorie malnutrition (via D51.-), E44 — Protein-calorie malnutrition of moderate and mild degree (via D51.-), E45 — Retarded development following protein-calorie malnutrition (via D51.-), E46 — Unspecified protein-calorie malnutrition (via D51.-), E50 — Vitamin A deficiency (via D51.-), E50-E64 — Other nutritional deficiencies (E50-E64) (via D51.-), E51 — Thiamine deficiency (via D51.-), E52 — Niacin deficiency [pellagra] (via D51.-), E53 — Deficiency of other B group vitamins (via D51.-), E53.8 — Deficiency of other specified B group vitamins (via D51.-), E54 — Ascorbic acid deficiency (via D51.-), E55 — Vitamin D deficiency (via D51.-), E56 — Other vitamin deficiencies (via D51.-), E58 — Dietary calcium deficiency (via D51.-), E59 — Dietary selenium deficiency (via D51.-), E60 — Dietary zinc deficiency (via D51.-), +3 more.

These codes’ tabular lists name this diagnosis as distinct — both may be reported when both are documented.

Referenced by 2 Code First instructions across 2 chapters: I21.A1 — Myocardial infarction type 2 (via D51.-), M90.5 — Osteonecrosis in diseases classified elsewhere (via D51.-).

Each of these codes carries a Code First note naming this condition — when that code is reported, THIS code is sequenced first, ahead of it.

MS-DRG Grouper Relationships (FY2027)

Potential MS-DRG participation — not a DRG assignment.

FY2027 MS-DRG: not on the CMS CC/MCC list — as a secondary diagnosis this code does not change MS-DRG severity for that release.

Named in the grouper logic of 2 MS-DRGs: DRG 811 (MDC 16), DRG 812 (MDC 16).

From the CMS MS-DRG Definitions Manual (Appendices B and C). Actual DRG assignment depends on the complete claim.

Clinical classification (AHRQ CCSR):BLD001 — Nutritional anemia (default).

Clinical Classifications Software Refined (CCSR) for ICD-10-CM Diagnoses. Healthcare Cost and Utilization Project (HCUP), Agency for Healthcare Research and Quality.

Related Codes

Same clinical category (CCSR)

AHRQ's Clinical Classifications Software groups these diagnoses under the same clinical category (Nutritional anemia).

D50.0 — Iron deficiency anemia secondary to blood loss (chronic), D50.1 — Sideropenic dysphagia, D50.8 — Other iron deficiency anemias, D50.9 — Iron deficiency anemia, unspecified, D51.0 — Vitamin B12 deficiency anemia due to intrinsic factor deficiency, D51.1 — Vitamin B12 deficiency anemia due to selective vitamin B12 malabsorption with proteinuria, D51.3 — Other dietary vitamin B12 deficiency anemia, D51.8 — Other vitamin B12 deficiency anemias, D51.9 — Vitamin B12 deficiency anemia, unspecified, D52.0 — Dietary folate deficiency anemia, D52.1 — Drug-induced folate deficiency anemia, D52.8 — Other folate deficiency anemias, D52.9 — Folate deficiency anemia, unspecified, D53.0 — Protein deficiency anemia, D53.1 — Other megaloblastic anemias, not elsewhere classified, D53.2 — Scorbutic anemia, D53.8 — Other specified nutritional anemias, D53.9 — Nutritional anemia, unspecified

Same Index main term, other category

The ICD-10-CM Index to Diseases and Injuries files this code under the main term “Anemia”; these codes share that main term but sit in a different category of the Tabular List.

D46.1 — Refractory anemia with ring sideroblasts (refractory, sideroblastic), D46.20 — Refractory anemia with excess of blasts, unspecified (refractory, with, excess of blasts), D46.21 — Refractory anemia with excess of blasts 1 (refractory, with, excess of blasts, 1), D46.22 — Refractory anemia with excess of blasts 2 (refractory, with, excess of blasts, 2), D46.4 — Refractory anemia, unspecified (refractory), D46.9 — Myelodysplastic syndrome, unspecified (myelodysplastic), D47.Z9 — Other specified neoplasms of uncertain behavior of lymphoid, hematopoietic and related tissue (myeloproliferative), D50.0 — Iron deficiency anemia secondary to blood loss (chronic) (factitious), D50.8 — Other iron deficiency anemias (Witts'), D50.9 — Iron deficiency anemia, unspecified (Faber's), D52.0 — Dietary folate deficiency anemia (goat's milk), D52.1 — Drug-induced folate deficiency anemia (deficiency, folate, drug-induced), D52.8 — Other folate deficiency anemias (macrocytic, tropical), D52.9 — Folate deficiency anemia, unspecified (folatedeficiency), D53.0 — Protein deficiency anemia (orotaciduric), D53.1 — Other megaloblastic anemias, not elsewhere classified (diphasic), D53.2 — Scorbutic anemia (scorbutic), D53.8 — Other specified nutritional anemias (due to, deficiency, zinc), D53.9 — Nutritional anemia, unspecified (macrocytic), D55.0 — Anemia due to glucose-6-phosphate dehydrogenase [G6PD] deficiency (favism), +258 more

Lab tests where this diagnosis supports Medicare coverage (NCD)

Medicare's National Coverage Determination (NCD) program lists this diagnosis as medical justification for these lab tests.

Iron Panel, Prothrombin Time Test and INR (PT/INR)

Contextual Map

Every relationship of D51.2 in one view: hierarchy, official tabular instructions in both directions, clinical classification, risk adjustment, MS-DRG participation, index terms and change history — each edge carrying the CMS source it derives from.

Run D51.2 with these 12 related codes in Claim Check

Hierarchy

Referenced by Excludes1 notes

Referenced by Excludes2 notes (23)

Referenced by Code First instructions

Clinical classification (CCSR)

MS-DRG Grouper

MDC crossing

  • MDC 16 — Diseases and Disorders of Blood, Blood Forming Organs and Immunologic Disorders[MDC crossing]: “Diseases and Disorders of Blood, Blood Forming Organs and Immunologic Disorders — the grouper's crossing between diagnoses and procedures: a principal diagnosis sets the MDC, and same-MDC procedures move the stay to its surgical DRGs. 1,615 same-MDC procedures group here; browse them on the MDC page.”— CMS MS-DRG Definitions Manual · FY2027

Index entries

  • Anemia (essential) (general) (hemoglobin deficiency) (infantile) (primary) (profound), deficiency, transcobalamin II[Index term]— CMS ICD-10-CM Index to Diseases and Injuries · icd10cm-fy2027
  • Anemia (essential) (general) (hemoglobin deficiency) (infantile) (primary) (profound), due to (in) (with), transcobalamin II deficiency[Index term]— CMS ICD-10-CM Index to Diseases and Injuries · icd10cm-fy2027
  • Deficiency, deficient, transcobalamine II (anemia)[Index term]— CMS ICD-10-CM Index to Diseases and Injuries · icd10cm-fy2027

Nearest codes

Change history

  • FY2016 — In the code set at ICD-10-CM adoption [Change history]— CMS release files (code change ledger) · icd10cm-fy2016

Reference

Index terms and tables, published questions and FAQ, every source behind this page with its release and checksum, the date-of-service check and the complete change history.

Indexed Clinical Terms (3)

Official source data — entries quoted as published, in the Index’s own lookup phrasing

Clinical term phrases from the official ICD-10-CM Index to Diseases and Injuries that map to this code. These are alphabetic-index entries shown as the Index writes them — lookup phrasing, not necessarily the wording of a final diagnosis.

Sources for this page

Codes, titles, notes, index terms and mappings on this page are transcribed from the datasets below. Relationships MedCoder computed and text MedCoder wrote are labelled where they appear.

Code, title, tabular notes and index terms Official source data
CMS/CDC ICD-10-CM FY2027 tabular list, index and tables, effective October 1, 2026 Release, file and checksum · Publisher’s page
Coding guidelines Official source data
ICD-10-CM Official Guidelines for Coding and Reporting (FY2027), quoted by section Release, file and checksum · Publisher’s page
Claim edits Official source data
CMS Definitions of Medicare Code Edits — v44.0 (October 2026) Release, file and checksum · Publisher’s page
Inpatient payment groups Official source data
CMS MS-DRG Definitions Manual (incl. Appendix B diagnosis index, Appendix C CC/MCC list, Appendix E procedure index) and IPPS Final Rule tables — v44 Release, file and checksum · Publisher’s page
Change history and date-of-service validity Official source data
CMS ICD-10-CM release addenda, ingested release by release into the change ledger Release, file and checksum · Publisher’s page
Comparisons, relationships and the contextual map MedCoder-derived relationship
Computed by MedCoder from the tabular notes and tables above; every derived relationship is marked as derived where it appears
Summary and FAQ answers MedCoder editorial explanation
Written by MedCoder to explain the sources above: drafted with AI assistance, checked by a person against the release files, and labelled as MedCoder text where it appears. Not official text.

Current data releases:ICD-10-CM FY2027 · ICD-10-PCS FY2027 · HCPCS October 2026 · MS-DRG v44 · Medicare Code Editor v44.0 · NCCI PTP Q4 2026 · MUE Q4 2026 · NCD code lists 2026-01 · LCD export September 20, 2026 · All releases and sources

Labels on this page: Official source data · MedCoder-derived relationship · MedCoder editorial explanation. How to read the labels · All data sources and release dates · CMS coding rules

Cite this page

Reference this page in a research guide, syllabus or article. The release is included because code content changes each year.

MedCoder.ai. "D51.2 — Transcobalamin II deficiency." ICD-10-CM FY2027. https://medcoder.ai/icd10/code/d51.2-transcobalamin-ii-deficiency

Change history

  • FY2016 — October 1, 2015
    In the code set at ICD-10-CM adoption
    Transcobalamin II deficiency

No changes since FY2016 — additions, deletions, description changes and billable-status changes are tracked through FY2027, and none are recorded for this code. Note changes are tracked from FY2027 only.

Nearest Codes in This Family

Official ICD-10-CM classifications closest to D51.2 in its code family, with their registry titles.

View all codes in the D51 family