2027 ICD-10-CM Diagnosis Code Z85.821Personal history of Merkel cell carcinoma
Z85.821 is a billable ICD-10-CM diagnosis code for personal history of Merkel cell carcinoma. It is valid on HIPAA claims for fiscal year 2027 (October 1, 2026 through September 30, 2027) and groups to MS-DRG 826 through 830, 843 through 845. The code is not accepted as a principal diagnosis by the Medicare Code Editor and exempt from POA reporting. Coders also document this condition as history of merkel cell carcinoma. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Personal history of malignant neoplasm.
Code Identity
Code Classification
Code EditsBilling
Medicare Code Editor checks that affect claim validity for Z85.821.
Present on Admission (POA)Billing
Z85.821 is exempt from POA reporting on inpatient claims to general acute care hospitals. Review the other POA exempt codes in Persons with potential health hazards related to family and personal history and certain conditions influencing health status (Z77-Z99).
Approximate SynonymsGuidance
Alternate terms and clinical phrases that map to this code.
- History of merkel cell carcinoma
Instructional NotesGuidance
Instructions from the official ICD-10-CM Tabular List that apply to Z85.821: its own notes plus those printed at Z85, block Z77-Z99, and Chapter 21. A note printed at a category, block or chapter applies to every code under it.
Applicable To
Conditions this code is used for: synonyms of the title or, for "other specified" codes, the conditions assigned to it. The list is not exhaustive.
- Conditions classifiable to C4A
Excludes2
Not included here: the excluded condition is not part of this code, but a patient may have both, so both codes may be reported.
Code First
The underlying condition named in the note is sequenced before this code.
Code Also
A second code may be needed to fully describe the condition; the note gives no sequencing direction.
Notes
General instructions on how these codes are used.
- Z codes represent reasons for encounters. A corresponding procedure code must accompany a Z code if a procedure is performed. Categories Z00-Z99 are provided for occasions when circumstances other than a disease, injury or external cause classifiable to categories A00-Y89 are recorded as 'diagnoses' or 'problems'. This can arise in two main ways:
- (a) When a person who may or may not be sick encounters the health services for some specific purpose, such as to receive limited care or service for a current condition, to donate an organ or tissue, to receive prophylactic vaccination (immunization), or to discuss a problem which is in itself not a disease or injury.
- (b) When some circumstance or problem is present which influences the person's health status but is not in itself a current illness or injury.
Source: CMS ICD-10-CM Tabular List. How to read instructional notes.
Referenced in Other NotesGuidance
Instructional notes printed at other codes that name Z85.821, its category, or a range that includes it.
Excludes2 2
These codes carry an Excludes2 note naming Z85.821: its condition is not part of those codes, and both may be reported when the patient has both.
- Z85.831 Personal history of malignant neoplasm of soft tissuepersonal history of malignant neoplasm of skin (Z85.82-) names Z85.82-, which includes this code
- Z86.0 Personal history of in-situ and benign neoplasms and neoplasms of uncertain behaviorpersonal history of malignant neoplasms (Z85.-) names Z85.-, which includes this code
Use Additional Code 2
These codes say to use an additional code from the note, and Z85.821 is one of the codes named.
- Z08 Encounter for follow-up examination after completed treatment for malignant neoplasmcode to identify the personal history of malignant neoplasm (Z85.-) names Z85.-, which includes this code
- Z15.0 Genetic susceptibility to malignant neoplasmcode, if applicable, for any personal history of malignant neoplasm (Z85.-) names Z85.-, which includes this code
Index to Diseases and InjuriesGuidance
Alphabetical index entries that point to this code.
personal (of) See Also: History, family (of);
Merkel cell Z85.821
Merkel cell Z85.821
Merkel cell carcinoma (skin) Z85.821
Clinical ClassificationClinical
AHRQ’s CCSR groups this code into broader clinical categories.
Patient EducationClinical
Skin Cancer
Skin cancer is the most common form of cancer in the United States. The two most common types are basal cell cancer and squamous cell cancer. They usually form on the head, face, neck, hands, and arms. Another type of skin cancer, melanoma, is more dangerous but less common.
Read the full article at MedlinePlus
Courtesy of MedlinePlus, a service of the U.S. National Library of Medicine.
Convert Z85.821 to ICD-9-CMHistory
The closest ICD-9-CM equivalents under the General Equivalence Mappings.
Code HistoryHistory
Questions About Z85.821Overview
What is the ICD-10 code for personal history of Merkel cell carcinoma?
The ICD-10-CM code for personal history of Merkel cell carcinoma is Z85.821 (sometimes written as Z85821). It is billable on HIPAA-covered claims from October 1, 2026 through September 30, 2027.
Is Z85.821 (Personal history of malignant neoplasm of skin) a billable code?
Yes. This is a billable ICD-10-CM code, specific enough to report personal history of Merkel cell carcinoma on HIPAA-covered claims from October 1, 2026 through September 30, 2027.
What MS-DRG does Z85.821 group to?
On inpatient claims, personal history of Merkel cell carcinoma maps to MS-DRG 844, 827, 829, 843, 828, 826, 830, 845, with relative weights from 0.8443 to 4.7560 depending on complications. Higher weights mean higher Medicare reimbursement.
Can Z85.821 be a principal diagnosis?
No. The Medicare Code Editor rejects this code as a principal diagnosis because personal history of Merkel cell carcinoma describes a circumstance that influences health status rather than a current illness. Report it as a secondary diagnosis.
Is Z85.821 exempt from POA reporting?
Yes. CMS lists this code among those exempt from present on admission reporting, so hospitals do not assign a POA indicator for personal history of Merkel cell carcinoma on inpatient claims. The code appears in the Persons with potential health hazards related to family and personal history and certain conditions influencing health status (Z77-Z99) range of the CMS exempt list.
