MS-DRG 179 – Respiratory Infections and Inflammations without CC/MCC
A Medical DRG in MDC 04 (Diseases & Disorders of the Respiratory System). Inpatient cases group to DRG 179 when the ICD-10-CM principal diagnosis is one of the 63 codes listed below and no secondary diagnosis on the CC or MCC lists is present. Its FY 2026 relative weight is 0.7550 with a geometric mean length of stay of 2.4 days.
Severity family
The grouper first assigns the case to MDC 04 from the principal diagnosis and finds no qualifying operating-room procedure (this is a Medical DRG; ICD-10-PCS codes do not drive assignment here), then applies the severity split from secondary diagnoses: with MCC → 177; with CC → 178; without CC/MCC → 179.
Principal Diagnosis Codes 63 codes · 33 categories
A02 Other salmonella infections1 code
- A02.22 Salmonella pneumonia
A06 Amebiasis1 code
- A06.5 Amebic lung abscess
A15 Respiratory tuberculosis7 codes
A20 Plague1 code
- A20.2 Pneumonic plague
A21 Tularemia1 code
- A21.2 Pulmonary tularemia
A22 Anthrax1 code
- A22.1 Pulmonary anthrax
A31 Infection due to other mycobacteria1 code
- A31.0 Pulmonary mycobacterial infection
A42 Actinomycosis1 code
- A42.0 Pulmonary actinomycosis
A43 Nocardiosis1 code
- A43.0 Pulmonary nocardiosis
A48 Other bacterial diseases, not elsewhere classified1 code
- A48.1 Legionnaires' disease
A52 Late syphilis1 code
- A52.72 Syphilis of lung and bronchus
B01 Varicella [chickenpox]1 code
- B01.2 Varicella pneumonia
B05 Measles1 code
- B05.2 Measles complicated by pneumonia
B25 Cytomegaloviral disease1 code
- B25.0 Cytomegaloviral pneumonitis
B37 Candidiasis1 code
- B37.1 Pulmonary candidiasis
B38 Coccidioidomycosis3 codes
B39 Histoplasmosis3 codes
B44 Aspergillosis1 code
- B44.0 Invasive pulmonary aspergillosis
B58 Toxoplasmosis1 code
- B58.3 Pulmonary toxoplasmosis
B59 Pneumocystosis1 code
- B59 Pneumocystosis
B66 Other fluke infections1 code
- B66.4 Paragonimiasis
B67 Echinococcosis1 code
- B67.1 Echinococcus granulosus infection of lung
E84 Cystic fibrosis1 code
- E84.0 Cystic fibrosis with pulmonary manifestations
J10 Influenza due to other identified influenza virus3 codes
J11 Influenza due to unidentified influenza virus2 codes
J15 Bacterial pneumonia, not elsewhere classified10 codes
- J15.0 Pneumonia due to Klebsiella pneumoniae
- J15.1 Pneumonia due to Pseudomonas
- J15.20 Pneumonia due to staphylococcus, unspecified
- J15.211 Pneumonia due to Methicillin susceptible Staphylococcus aureus
- J15.212 Pneumonia due to Methicillin resistant Staphylococcus aureus
- J15.29 Pneumonia due to other staphylococcus
- J15.5 Pneumonia due to Escherichia coli
- J15.61 Pneumonia due to Acinetobacter baumannii
- J15.69 Pneumonia due to other Gram-negative bacteria
- J15.8 Pneumonia due to other specified bacteria
J17 Pneumonia in diseases classified elsewhere1 code
- J17 Pneumonia in diseases classified elsewhere
J69 Pneumonitis due to solids and liquids3 codes
J85 Abscess of lung and mediastinum4 codes
J98 Other respiratory disorders2 codes
R76 Other abnormal immunological findings in serum2 codes
U07 Emergency use of U071 code
- U07.1 COVID-19
Procedure Codes
Severity Exclusions 11 codes
When a case groups to DRG 179, these secondary diagnoses do not count as a CC or MCC for the severity split.
View excluded secondary diagnoses11
- A48.1 Legionnaires' disease
- J15.0 Pneumonia due to Klebsiella pneumoniae
- J15.1 Pneumonia due to Pseudomonas
- J15.20 Pneumonia due to staphylococcus, unspecified
- J15.211 Pneumonia due to methicillin suscep staph
- J15.212 Pneumonia due to Methicillin resistant Staphylococcus aureus
- J15.29 Pneumonia due to other staphylococcus
- J15.5 Pneumonia due to Escherichia coli
- J15.61 Pneumonia due to Acinetobacter baumannii
- J15.69 Pneumonia due to other Gram-negative bacteria
- J15.8 Pneumonia due to other specified bacteria
Frequently Asked Questions
What is MS-DRG 179?
MS-DRG 179 (Respiratory Infections and Inflammations without CC/MCC) is a medical DRG in MDC 04 (Diseases & Disorders of the Respiratory System). Its FY 2026 relative weight is 0.7550 with a geometric mean length of stay of 2.4 days.
What is the difference between DRG 177, 178, 179?
All 3 share the same base category; the severity of secondary diagnoses separates them: 177 (with MCC), 178 (with CC), 179 (without CC/MCC). A major complication or comorbidity (MCC) places the case in the highest-weighted DRG of the family; a CC in the middle; neither in the lowest.
How many diagnosis codes group to DRG 179?
63 ICD-10-CM principal diagnosis codes group to this DRG, spanning 33 three-character categories.
What is the relative weight of DRG 179?
The FY 2026 relative weight of this DRG is 0.7550, meaning reimbursement of roughly 0.76 times the average Medicare inpatient case. Multiply by a hospital's blended base rate for the approximate payment.
