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ICD-10-CM 2027 diagnosis code

Z55.5Less than a high school diploma

✓ Billable / specificPOA exemptNot a principal dx

Z55.5 is a valid, billable ICD-10-CM code for less than a high school diploma. It can be reported on claims for dates of service from October 1, 2026 – September 30, 2027.

Looking up by condition? See ICD-10 code for Less than a high school diploma.

Code last changed in FY2022 (effective October 1, 2021). Source: official FY2027 ICD-10-CM release from CDC/NCHS and CMS. Page updated September 29, 2026. About our data

About Z55.5

Z55.5 is the ICD-10-CM diagnosis code for less than a high school diploma. It belongs to category Z55 (problems related to education and literacy), block Z55-Z65 (persons with potential health hazards related to socioeconomic and psychosocial circumstances) and chapter 21 (factors influencing health status and contact with health services). It is billable, so it can be reported on its own for dates of service from October 1, 2026 through September 30, 2027.

Within Z55 (problems related to education and literacy), Z55.5 is specifically for less than a high school diploma. Related codes cover Illiteracy and low-level literacy (Z55.0), Schooling unavailable and unattainable (Z55.1), failed school examinations (Z55.2), underachievement in school (Z55.3), educational maladjustment and discord with teachers and classmates (Z55.4), problems related to health literacy (Z55.6), other problems related to education and literacy (Z55.8) and unspecified (Z55.9).

It is not a CC or MCC, so as a secondary diagnosis it doesn't change the MS-DRG severity level.

In MS-DRG v44.0, it is part of the grouping logic for DRG 951 (Other Factors Influencing Health Status, relative weight 0.5577), in MDC 23 (Factors Influencing Health Status and Other Contacts with Health Services), as a principal or secondary diagnosis. The DRG a claim lands in depends on the principal diagnosis, procedures and any CC/MCC secondary diagnoses.

It is not acceptable as the principal diagnosis for an inpatient stay; it may be reported as a secondary diagnosis.

It is exempt from present-on-admission (POA) reporting, so no POA indicator is required.

It was added in FY2022, effective October 1, 2021.

Coding notes

Applicable toConditions and synonyms classified to this code
  • No general equivalence degree (GED)

Notes that apply from higher levels

Instructions written at a parent level also apply to Z55.5.

› From Z55 Problems related to education and literacy
Excludes1
  • disorders of psychological development (F80-F89)

Broader instructions also apply from Chapter 21: Factors influencing health status and contact with health services.

Alphabetic index entries

4 entries

Terms in the official ICD-10-CM index that lead to Z55.5.

MS-DRG v44.0 grouping

All DRGs →

Inpatient MS-DRGs this diagnosis can group to, as the principal or a secondary diagnosis, depending on the rest of the claim.

MDC 23 · Factors Influencing Health Status and Other Contacts with Health Services

Code history

  1. 2016
  2. 2017
  3. 2018
  4. 2019
  5. 2020
  6. 2021
  7. 2022
  8. 2023
  9. 2024
  10. 2025
  11. 2026
  12. 2027
  • FY2022 (effective 10/1/2021): Added
  • No changes since FY2022.

Common questions about Z55.5

Is Z55.5 billable?

Yes. Z55.5 is a billable/specific ICD-10-CM code valid for FY2027 (October 1, 2026 – September 30, 2027).

Can Z55.5 be used as a principal diagnosis?

No. It is not acceptable as the principal diagnosis for an inpatient stay; it may be reported as a secondary diagnosis.

Is Z55.5 a CC or MCC?

No. Z55.5 is neither a CC nor an MCC under MS-DRG v44.0.

What DRG does Z55.5 group to?

Z55.5 is used in the MS-DRG v44.0 logic for MS-DRG 951 (Other Factors Influencing Health Status). Which one applies depends on whether it is the principal diagnosis and on the rest of the claim.