2026 ICD-10-CM Diagnosis Code D74.9Methemoglobinemia, unspecified
ICD-10-CM Codes›D50–D89›D70-D77›D74
- Billable — Valid for Submission
- CC — Complication or Comorbidity
- Chronic Condition
D74.9 is a billable ICD-10-CM diagnosis code for methemoglobinemia, unspecified. It is valid on HIPAA claims for fiscal year 2026 (October 1, 2025 through September 30, 2026) and groups to MS-DRG 811 through 812. As a secondary diagnosis, it counts as a complication or comorbidity (CC) and moves an inpatient stay to a higher severity level within its MS-DRG family. It does not count, however, when the principal diagnosis is one of 24 closely related codes. Coders also document this condition as methemoglobinemia. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Other specified and unspecified hematologic conditions.
Code Identity
Code Classification
Approximate SynonymsGuidance
Alternate terms and clinical phrases that map to this code.
- Methemoglobinemia
Index to Diseases and InjuriesGuidance
Alphabetical index entries that point to this code.
Methemoglobinemia D74.9
Clinical ClassificationClinical
AHRQ’s CCSR groups this code into broader clinical categories.
Clinical InformationClinical
Methemoglobinemia
the presence of methemoglobin in the blood, resulting in cyanosis. a small amount of methemoglobin is present in the blood normally, but injury or toxic agents convert a larger proportion of hemoglobin into methemoglobin, which does not function reversibly as an oxygen carrier. methemoglobinemia may be due to a defect in the enzyme nadh methemoglobin reductase (an autosomal recessive trait) or to an abnormality in hemoglobin m (an autosomal dominant trait). (dorland, 27th ed)
Patient EducationClinical
Blood Disorders
Your blood is living tissue made up of liquid and solids. The liquid part, called plasma, is made of water, salts and protein. Over half of your blood is plasma. The solid part of your blood contains red blood cells, white blood cells and platelets.
Read the full article at MedlinePlus
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Convert D74.9 to ICD-9-CMHistory
The closest ICD-9-CM equivalents under the General Equivalence Mappings.
Code HistoryHistory
Questions About D74.9Overview
What is the ICD-10 code for methemoglobinemia, unspecified?
The ICD-10-CM code for methemoglobinemia, unspecified is D74.9 (sometimes written as D749). It is billable on HIPAA-covered claims from October 1, 2025 through September 30, 2026.
Is D74.9 (Methemoglobinemia) a billable code?
Yes. This is a billable ICD-10-CM code, specific enough to report methemoglobinemia, unspecified on HIPAA-covered claims from October 1, 2025 through September 30, 2026.
What MS-DRG does D74.9 group to?
When methemoglobinemia, unspecified is the principal diagnosis on an inpatient stay, it groups to MS-DRG 811, 812, with relative weights from 0.9182 to 1.4043 depending on complications. Higher weights mean higher Medicare reimbursement.
Is D74.9 a CC or MCC?
CMS lists D74.9 as a CC (complication or comorbidity) for FY 2026. Reported as a secondary diagnosis, it moves the inpatient stay to a higher-weighted DRG within its severity family. It does not count when the principal diagnosis is one of the 24 closely related codes in its exclusion list.
What is the ICD-9 equivalent of D74.9?
Under the General Equivalence Mappings, methemoglobinemia, unspecified converts to ICD-9-CM 289.7 (methemoglobinemia). The mapping is approximate, so confirm the match fits the documentation.
