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Z85.850 ICD-10-CM Code: Personal history of malignant neoplasm of thyroid

Compare with another codeCheck this code on a claim

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

Coding at a Glance

Tabular directives
2 Excludes2 · 7 use-additional codes · 1 code-first instruction · 1 code-also instruction

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.

Code firstSequence the underlying condition before this code
  • any follow-up examination after treatment of malignant neoplasm (Z08)
Use additional codeReport with this code when documented
  • code to identify:
  • alcohol use and dependence (F10.-)
  • exposure to environmental tobacco smoke (Z77.22)
  • history of tobacco dependence (Z87.891)

+3 more in Instructions

Code alsoMay be needed with this code
  • any follow-up examination (Z08-Z09)
Excludes2Not included here; may be reported together
  • personal history of benign neoplasm (Z86.01-)
  • personal history of carcinoma-in-situ (Z86.00-)

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 826 — MYELOPROLIFERATIVE DISORDERS OR POORLY DIFFERENTIATED NEOPLASMS WITH MAJOR O.R. PROCEDURES WITH MCC (MDC 17)
  • MS-DRG 827 — MYELOPROLIFERATIVE DISORDERS OR POORLY DIFFERENTIATED NEOPLASMS WITH MAJOR O.R. PROCEDURES WITH CC (MDC 17)
  • MS-DRG 828 — MYELOPROLIFERATIVE DISORDERS OR POORLY DIFFERENTIATED NEOPLASMS WITH MAJOR O.R. PROCEDURES WITHOUT CC/MCC (MDC 17)
  • MS-DRG 829 — MYELOPROLIFERATIVE DISORDERS OR POORLY DIFFERENTIATED NEOPLASMS WITH OTHER PROCEDURES WITH CC/MCC (MDC 17)
  • MS-DRG 830 — MYELOPROLIFERATIVE DISORDERS OR POORLY DIFFERENTIATED NEOPLASMS WITH OTHER PROCEDURES WITHOUT CC/MCC (MDC 17)
  • MS-DRG 843 — OTHER MYELOPROLIFERATIVE DISORDERS OR POORLY DIFFERENTIATED NEOPLASTIC DIAGNOSES WITH MCC (MDC 17)
  • MS-DRG 844 — OTHER MYELOPROLIFERATIVE DISORDERS OR POORLY DIFFERENTIATED NEOPLASTIC DIAGNOSES WITH CC (MDC 17)
  • MS-DRG 845 — OTHER MYELOPROLIFERATIVE DISORDERS OR POORLY DIFFERENTIATED NEOPLASTIC DIAGNOSES WITHOUT CC/MCC (MDC 17)

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 Z85.850 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 Z85.850 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 Z85

Code First

Underlying conditions that must be sequenced before this code.

  • any follow-up examination after treatment of malignant neoplasm (Z08)

Source: inherited from Z85

Code Also

Additional codes that may be required to fully describe the encounter.

  • any follow-up examination (Z08-Z09)

Source: inherited from Z77-Z99

Use Additional Code

Supplementary codes the tabular list directs you to add.

  • Use additional code to identify:
  • alcohol use and dependence (F10.-)
  • exposure to environmental tobacco smoke (Z77.22)
  • history of tobacco dependence (Z87.891)
  • occupational exposure to environmental tobacco smoke (Z57.31)
  • tobacco dependence (F17.-)
  • tobacco use (Z72.0)

Source: inherited from Z85

Coder workflow for Z85.850

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

Before you code Z85.850

  1. Confirm the reason for the encounter this Z code records: a personal or family history — a condition no longer present or present in a relative — never a current condition. Check whether the code may be reported as first-listed or principal — some Z codes are limited to one position — and do not report a history or status code for a condition documented as current. Z code categories and their reporting positions (Guidelines I.C.21.c.4, I.C.21.c.15).

    Guide: History codes (Z codes) →

Choose the right path

  1. Is the underlying (etiologic) condition the Code First note names documented?
    Yes → Sequence the underlying condition first, then Z85.850.
    No → Continue; do not add an underlying condition the record does not document.

    ReviewZ08

Consider Z85.850. Then work the Use Additional Code note and review the Code Also note, and confirm the code is valid for the date of service in the Verify section.

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).
The underlying (etiologic) condition
Named in the Code First note; sequenced before this code when documented (Guidelines I.A.13).
The conditions the Use Additional Code note names
Reported with this code when documented; a conditional instruction (“if applicable”, “if known”) applies only when the record supports it.
The reason for the encounter
Whether the code records the encounter’s purpose, a status, or a history — and whether it may be first-listed (Guidelines I.C.21.c).

Official instructions as workflow

  • Excludes2 — not part of Z85.850(2 notes)

    Coding workflow: The conditions named in this note are not included in Z85.850. When the record documents both, both may be reported; the note is a boundary, not a prohibition.

    CompareZ86.01, Z86.00

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

  • Code First — sequencing check(1 note)

    Coding workflow: Check whether the underlying or etiologic condition the note names is documented. When it is, sequence it before Z85.850. Do not add an underlying condition the record does not document.

    ReviewZ08

    See the official tabular notes · Guidelines I.A.13

  • Use Additional Code — after identifying Z85.850(7 notes)

    Coding workflow: Check whether the documentation supports the additional code(s) the note names, and report them with Z85.850 when it does. Where the instruction is conditional (“if applicable”, “if known”), it applies only when the record documents the condition.

    ReviewF10, Z77.22, Z87.891, Z57.31, F17, Z72.0

    See the official tabular notes · Guidelines I.A.13

  • Code Also — related condition(1 note)

    Coding workflow: Review the related condition when both are documented and the instruction applies. A Code Also note does not fix sequencing; the order follows the circumstances of the encounter.

    See the official tabular notes · Guidelines I.A.17

Coding decision scenarios

Pattern scenarios for this code’s structure — decision rules, not clinical cases

Documentation: The underlying condition the Code First note names is documented alongside this condition.

Coding question: How are the two sequenced?

Path: Review the Code First note.

Reason: The underlying condition is sequenced first and the manifestation follows (Guidelines I.A.13).

ReviewZ08

Documentation: A condition the Use Additional Code note names is documented.

Coding question: Is a second code reported with Z85.850?

Path: Review the Use Additional Code note and the code it names.

Reason: The additional code is reported when the record documents the condition; a conditional instruction applies only when its condition is met (Guidelines I.A.13).

ReviewF10, Z77.22, Z87.891, Z57.31, F17, Z72.0

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 Z85.850 with…

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

The codes most likely to be picked instead of Z85.850 — 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.

  • Z86.01— 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 personal history of benign neoplasm adds Z86.01; it is not part of this code and both may be reported when both are documented.

    Full comparison: Z85.850 vs Z86.01 →

  • Z86.00— 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 personal history of carcinoma-in-situ adds Z86.00; it is not part of this code and both may be reported when both are documented.

    Full comparison: Z85.850 vs Z86.00 →

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

Personal history of malignant neoplasm of thyroid is a billable ICD-10-CM diagnosis code (Z85.850).

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

Official source data — quoted verbatim from the CMS/NCHS Official Guidelines

Verbatim excerpts from the ICD-10-CM Official Guidelines for Coding and Reporting (CMS/NCHS) that govern this code.

Chapter 2: Neoplasms (C00-D49 )

Codes from subcategories Z85.0 – Z85.85 should only be assigned for the former site of a primary malignancy, not the site of a secondary malignancy. Code Z85.89 may be assigned for the former site(s) of either a primary or secondary malignancy.

Chapter 2: Neoplasms (C00-D49 )

d. Primary malignancy previously excised When a primary malignancy has been previously excised or eradicated from its site and there is no further treatment directed to that site and there is no evidence of any existing primary malignancy at that site, a code from category Z85, Personal history of malignant neoplasm, should be used to indicate the former site of the malignancy. Any mention of extension, invasion, or metastasis to another site is coded as a secondary malignant neoplasm to that site. The secondary site may be the principal or first-listed diagnosis with the Z85 code used as a secondary code. See section I.C.2.t. Secondary malignant neoplasm of lymphoid tissue.

Chapter 2: Neoplasms (C00-D49 )

When a primary malignancy has been previously excised or eradicated from its site, there is no further treatment (of the malignancy) directed to that site, and there is no evidence of any existing primary malignancy at that site, a code from category Z85, Personal history of malignant neoplasm, should be used to indicate the former site of the malignancy.

Chapter 21: Factors influencing health status and contact with health services (Z00-Z99)

The history Z code categories are: Z80 Family history of primary malignant neoplasm Z81 Family history of mental and behavioral disorders Z82 Family history of certain disabilities and chronic diseases (leading to disablement) Z83 Family history of other specific disorders Z84 Family history of other conditions Z85 Personal history of malignant neoplasm Z86 Personal history of certain other diseases Z87 Personal history of other diseases and conditions Z91.4- Personal history of psychological trauma, not elsewhere classified Z91.5- Personal history of self- harm Z91.81 History of falling Z91.82 Personal history of military deployment Z91.85 Personal history of military service Z92 Personal history of medical treatment Except: Z92.0, Personal history of contraception Except: Z92.82, Status post administration of tPA (rtPA) in a different facility within the last 24 hours prior to admission to a current facility

Decision Points

The directives on this code's own record, as a pre-claim checklist.

  1. Sequencing: 1 Code First instruction — the underlying condition is sequenced before this code when present. See the Code First notes
  2. 7 Use Additional Code instructions — report the named additional code(s) when the documentation supports them. See the Use Additional Code notes
  3. 1 Code Also note — a second code may apply; the guidelines leave its sequencing to the circumstances of the encounter. See the Code Also notes
  4. 2 Excludes2 entries — those conditions are not part of this code and may be reported additionally when documented. See the Excludes2 notes

Checklist rows are derived from this code's own official directives; the wording of each check is MedCoder editorial. The official notes themselves are in the sections each row links to.

Verify Before Coding

  • Principal-diagnosis restriction. The Medicare Code Editor lists this code as unacceptable as a principal diagnosis: it describes a circumstance influencing health status rather than a current illness or injury being treated. It is valid as a secondary diagnosis.

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 Z85.850 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 1 Excludes2 note: Z86.0 — Personal history of in-situ and benign neoplasms and neoplasms of uncertain behavior (via Z85.-).

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

Referenced by 2 Use Additional Code instructions: Z08 — Encounter for follow-up examination after completed treatment for malignant neoplasm (via Z85.-), Z15.0 — Genetic susceptibility to malignant neoplasm (via Z85.-).

These codes instruct coders to additionally report this code when it applies.

Referenced by 1 Code Also instruction: QA1 — Genetic disorders associated with neoplasms, not elsewhere classified (via Z85.-).

These codes suggest coding this condition alongside when both are present.

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 8 MS-DRGs: DRG 826 (MDC 17), DRG 827 (MDC 17), DRG 828 (MDC 17), DRG 829 (MDC 17), DRG 830 (MDC 17), DRG 843 (MDC 17), DRG 844 (MDC 17), DRG 845 (MDC 17).

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

Clinical classification (AHRQ CCSR):FAC027 — Personal history of malignant neoplasm (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

Principal diagnosis restriction (Medicare Code Editor)

Not acceptable as a principal diagnosis on an inpatient claim.

Same clinical category (CCSR)

AHRQ's Clinical Classifications Software groups these diagnoses under the same clinical category (Personal history of malignant neoplasm).

Z85.72 — Personal history of non-Hodgkin lymphomas, Z85.79 — Personal history of other malignant neoplasms of lymphoid, hematopoietic and related tissues, Z85.810 — Personal history of malignant neoplasm of tongue, Z85.818 — Personal history of malignant neoplasm of other sites of lip, oral cavity, and pharynx, Z85.819 — Personal history of malignant neoplasm of unspecified site of lip, oral cavity, and pharynx, Z85.820 — Personal history of malignant melanoma of skin, Z85.821 — Personal history of Merkel cell carcinoma, Z85.828 — Personal history of other malignant neoplasm of skin, Z85.830 — Personal history of malignant neoplasm of bone, Z85.831 — Personal history of malignant neoplasm of soft tissue, Z85.840 — Personal history of malignant neoplasm of eye, Z85.841 — Personal history of malignant neoplasm of brain, Z85.848 — Personal history of malignant neoplasm of other parts of nervous tissue, Z85.858 — Personal history of malignant neoplasm of other endocrine glands, Z85.89 — Personal history of malignant neoplasm of other organs and systems, Z85.9 — Personal history of malignant neoplasm, unspecified, Z92.21 — Personal history of antineoplastic chemotherapy, Z92.26 — Personal history of immune checkpoint inhibitor therapy, Z92.3 — Personal history of irradiation, Z92.850 — Personal history of Chimeric Antigen Receptor T-cell therapy, +43 more

Same Index main term, other category

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

Z83.79 — Family history of other diseases of the digestive system (family, disease or disorder, digestive), Z84.0 — Family history of diseases of the skin and subcutaneous tissue (family, skin condition), Z84.11 — Family history of APOL1-mediated kidney disease [AMKD] (family, disease or disorder, kidney, APOL1-mediated), Z84.19 — Family history of other disorders of kidney and ureter (family, disease or disorder, kidney), Z84.2 — Family history of other diseases of the genitourinary system (family, disease or disorder, genitourinary NEC), Z84.3 — Family history of consanguinity (family, consanguinity), Z84.81 — Family history of carrier of genetic disease (family, genetic disease carrier), Z84.82 — Family history of sudden infant death syndrome (family, SIDS), Z84.89 — Family history of other specified conditions (family, allergy NEC), Z84.A — Family history of exposure to diethylstilbestrol (family, exposure to diethylstilbestrol), Z86.000 — Personal history of in-situ neoplasm of breast (personal, in situ neoplasm, breast), Z86.001 — Personal history of in-situ neoplasm of cervix uteri (personal, dysplasia, cervical, severe), Z86.002 — Personal history of in-situ neoplasm of other and unspecified genital organs (personal, dysplasia, vulvar, severe), Z86.003 — Personal history of in-situ neoplasm of oral cavity, esophagus and stomach (personal, in situ neoplasm, stomach), Z86.004 — Personal history of in-situ neoplasm of other and unspecified digestive organs (personal, neoplasia, anal intraepithelial, III [AIN III]), Z86.005 — Personal history of in-situ neoplasm of middle ear and respiratory system (personal, in situ neoplasm, middle ear), Z86.006 — Personal history of melanoma in-situ (personal, melanoma, in situ), Z86.007 — Personal history of in-situ neoplasm of skin (personal, in situ neoplasm, skin), Z86.008 — Personal history of in-situ neoplasm of other site (personal, in situ neoplasm, specified NEC), Z86.00A — Personal history of in-situ neoplasm of the fallopian tube(s) (personal, in situ neoplasm, fallopian tube), +207 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.

Thyroid Stimulating Hormone (TSH)

Contextual Map

Every relationship of Z85.850 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 Z85.850 with these 4 related codes in Claim Check

Hierarchy

Lifecycle MedCoder-derived

Referenced by Excludes2 notes

Referenced by Use Additional Code instructions

Referenced by Code Also instructions

Clinical classification (CCSR)

MS-DRG Grouper

MDC crossing

  • MDC 17 — Myeloproliferative Diseases and Disorders, Poorly Differentiated Neoplasms[MDC crossing]: “Myeloproliferative Diseases and Disorders, Poorly Differentiated Neoplasms — 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. 4,735 same-MDC procedures group here; browse them on the MDC page.”— CMS MS-DRG Definitions Manual · FY2027

Index entries

  • History, personal (of), malignant neoplasm (of), thyroid[Index term]— CMS ICD-10-CM Index to Diseases and Injuries · icd10cm-fy2027

Nearest codes (40)

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 (1)

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 28, 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. "Z85.850 — Personal history of malignant neoplasm of thyroid." ICD-10-CM FY2027. https://medcoder.ai/icd10/code/z85.850-personal-history-of-malignant-neoplasm-of-thyroid

Change history

  • FY2016 — October 1, 2015
    In the code set at ICD-10-CM adoption
    Personal history of malignant neoplasm of thyroid

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 Z85.850 in its code family, with their registry titles.

View all codes in the Z85 family