ICD-10-CM 2027
ICD-10 code for Undiagnosed
From the official ICD-10-CM alphabetic index entry “Undiagnosed (disease)”. Page updated September 29, 2026.
About coding Undiagnosed
The ICD-10-CM code for Undiagnosed is R69 (Illness, unspecified).
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 has been part of ICD-10-CM since the code set took effect on October 1, 2015 and hasn't changed since.
Common questions about Undiagnosed ICD-10 codes
What is the ICD-10 code for Undiagnosed?
- R69 — Illness, unspecified.
Is R69 billable?
- Yes. R69 is a billable/specific ICD-10-CM code valid for FY2027 (October 1, 2026 – September 30, 2027).
Can R69 be used as a principal diagnosis?
- Yes. The Medicare Code Editor doesn't restrict R69 as a principal diagnosis.
Is R69 a CC or MCC?
- No. R69 is neither a CC nor an MCC under MS-DRG v44.0.