2027 ICD-10-CM Diagnosis Code R65.21Severe sepsis with septic shock
ICD-10-CM Codes›R00–R99›R50-R69›R65
- Billable — Valid for Submission
- MCC — Major Complication or Comorbidity
- Risk Adjusts — HCC 2
- Not a Principal Diagnosis
- Not Chronic
R65.21 is a billable ICD-10-CM diagnosis code for severe sepsis with septic shock. It is valid on HIPAA claims for fiscal year 2027 (October 1, 2026 through September 30, 2027) and groups to MS-DRG 870 through 872. As a secondary diagnosis, it counts as a major complication or comorbidity (MCC) and places an inpatient stay in the highest severity level of its MS-DRG family. It does not count, however, when the principal diagnosis is one of 48 closely related codes. The code is not accepted as a principal diagnosis by the Medicare Code Editor. As a symptom code, it should not be used as a principal diagnosis once a related definitive diagnosis has been established. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Septicemia and Shock.
For Medicare Advantage risk adjustment, R65.21 maps to CMS-HCC Category 2 (Septicemia, Sepsis, Systemic Inflammatory Response Syndrome/Shock) under the V28 model, adding a risk factor of about 0.500 for a community, non-dual, aged beneficiary in payment year 2027.
Code Identity
Code Classification
Code EditsBilling
Medicare Code Editor checks that affect claim validity for R65.21.
Medicare Risk Adjustment (HCC)Billing
R65.21 maps to a payment category in the CMS-HCC model used to risk-adjust Medicare Advantage payments. Weights are the published community factors for payment year 2027.
Source: CMS Payment Year 2027 risk adjustment mappings and model software. Weights are relative factors, not dollar amounts; a beneficiary's total RAF also includes demographics and interactions. Browse all CMS-HCC categories.
Approximate SynonymsGuidance
Alternate terms and clinical phrases that map to this code.
- Endotoxic shock
- Failed attempted termination of pregnancy with septic shock
- Failed attempted termination of pregnancy with shock
- Hyperdynamic septic shock
- Hypodynamic septic shock
- Induced termination of pregnancy complicated by postoperative shock
- Induced termination of pregnancy complicated by septic shock
- Induced termination of pregnancy complicated by shock
- Miscarriage complicated by shock
- Miscarriage with septic shock
- Postprocedural septic shock
- Pyrogenic shock
- Sepsis caused by Chromobacterium
- Sepsis due to ectopic pregnancy
- Sepsis due to infection caused by Neisseria meningitidis
- Sepsis following ectopic pregnancy
- Sepsis following induced termination of pregnancy
- Sepsis following molar pregnancy
- Septic shock
- Septic shock co-occurrent with acute organ dysfunction caused by anaerobic bacteria
- Septic shock co-occurrent with acute organ dysfunction caused by Haemophilus influenzae
- Septic shock co-occurrent with acute organ dysfunction caused by Meningococcus
- Septic shock co-occurrent with acute organ dysfunction caused by methicillin resistant Staphylococcus aureus
- Septic shock co-occurrent with acute organ dysfunction caused by methicillin susceptible Staphylococcus aureus
- Septic shock co-occurrent with acute organ dysfunction caused by Pneumococcus
- Septic shock co-occurrent with acute organ dysfunction caused by Pseudomonas
- Septic shock co-occurrent with acute organ dysfunction caused by Serratia
- Septic shock co-occurrent with acute organ dysfunction caused by Streptococcus
- Septic shock co-occurrent with acute organ dysfunction due to Chromobacterium
- Septic shock co-occurrent with acute organ dysfunction due to coagulase-negative Staphylococcus
- Septic shock co-occurrent with acute organ dysfunction due to Enterococcus
- Septic shock co-occurrent with acute organ dysfunction due to Gonococcus
- Septic shock co-occurrent with acute organ dysfunction due to Gram-positive coccus
- Septic shock co-occurrent with acute organ dysfunction due to Group A streptococcus
- Septic shock co-occurrent with acute organ dysfunction due to Group B streptococcus
- Septic shock co-occurrent with acute organ dysfunction due to Staphylococcus
- Septic shock due to transfusion
- Septic shock following ectopic pregnancy
- Septic shock following molar pregnancy
- Shock due to ectopic pregnancy
- Shock following molar pregnancy
Instructional NotesGuidance
Instructions from the official ICD-10-CM Tabular List that apply to R65.21: its own notes plus those printed at R65.2 and Chapter 18. A note printed at a category, block or chapter applies to every code under it.
Excludes1
Not coded here: the excluded code is never reported together with this one, unless the two conditions are unrelated.
- postprocedural septic shock (T81.12-)
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.
- underlying infection, such as:
- infection following a procedure (T81.4-)
- infections following infusion, transfusion and therapeutic injection (T80.2-)
- puerperal sepsis (O85)
- sepsis following complete or unspecified spontaneous abortion (O03.87)
- sepsis following ectopic and molar pregnancy (O08.82)
- sepsis following incomplete spontaneous abortion (O03.37)
- sepsis following (induced) termination of pregnancy (O04.87)
- sepsis NOS (A41.9)
Use Additional Code
Add a second code, after this one, to fully describe the condition.
- code to identify specific acute organ dysfunction, such as:
- acute kidney failure (N17.-)
- acute respiratory failure (J96.0-)
- critical illness myopathy (G72.81)
- critical illness polyneuropathy (G62.81)
- disseminated intravascular coagulopathy [DIC] (D65)
- encephalopathy (metabolic) (septic) (G93.41)
- hepatic failure (K72.0-)
Notes
General instructions on how these codes are used.
- This chapter includes symptoms, signs, abnormal results of clinical or other investigative procedures, and ill-defined conditions regarding which no diagnosis classifiable elsewhere is recorded.
- Signs and symptoms that point rather definitely to a given diagnosis have been assigned to a category in other chapters of the classification. In general, categories in this chapter include the less well-defined conditions and symptoms that, without the necessary study of the case to establish a final diagnosis, point perhaps equally to two or more diseases or to two or more systems of the body. Practically all categories in the chapter could be designated 'not otherwise specified', 'unknown etiology' or 'transient'. The Alphabetical Index should be consulted to determine which symptoms and signs are to be allocated here and which to other chapters. The residual subcategories, numbered .8, are generally provided for other relevant symptoms that cannot be allocated elsewhere in the classification.
- The conditions and signs or symptoms included in categories R00-R94 consist of:
- (a) cases for which no more specific diagnosis can be made even after all the facts bearing on the case have been investigated;
- (b) signs or symptoms existing at the time of initial encounter that proved to be transient and whose causes could not be determined;
- (c) provisional diagnosis in a patient who failed to return for further investigation or care;
- (d) cases referred elsewhere for investigation or treatment before the diagnosis was made;
- (e) cases in which a more precise diagnosis was not available for any other reason;
- (f) certain symptoms, for which supplementary information is provided, that represent important problems in medical care in their own right.
Source: CMS ICD-10-CM Tabular List. How to read instructional notes.
Referenced in Other NotesGuidance
Instructional notes printed at other codes that name R65.21, its category, or a range that includes it.
Excludes1 2
These codes carry an Excludes1 note naming R65.21: they are not reported together with it, unless the two conditions are unrelated.
Excludes2 1
These codes carry an Excludes2 note naming R65.21: its condition is not part of those codes, and both may be reported when the patient has both.
- R57.0 Cardiogenic shockseptic shock (R65.21)
Use Additional Code 9
These codes say to use an additional code from the note, and R65.21 is one of the codes named.
- O03.37 Sepsis following incomplete spontaneous abortioncode to identify severe sepsis, if applicable (R65.2-) names R65.2-, which includes this code
- O03.87 Sepsis following complete or unspecified spontaneous abortioncode to identify severe sepsis, if applicable (R65.2-) names R65.2-, which includes this code
- O04.87 Sepsis following (induced) termination of pregnancycode to identify severe sepsis, if applicable (R65.2-) names R65.2-, which includes this code
- O07.37 Sepsis following failed attempted termination of pregnancycode (R65.2-) to identify severe sepsis, if applicable names R65.2-, which includes this code
- O08.82 Sepsis following ectopic and molar pregnancycode (R65.2-) to identify severe sepsis, if applicable names R65.2-, which includes this code
- O85 Puerperal sepsiscode (R65.2-) to identify severe sepsis, if applicable names R65.2-, which includes this code
- P36 Bacterial sepsis of newborncode(s), if applicable, to identify severe sepsis (R65.2-) and associated acute organ dysfunction(s) names R65.2-, which includes this code
- T80.2 Infections following infusion, transfusion and therapeutic injectioncode (R65.2-) to identify severe sepsis, if applicable names R65.2-, which includes this code
- T81.4 Infection following a procedurecode (R65.2-) to identify severe sepsis, if applicable names R65.2-, which includes this code
Index to Diseases and InjuriesGuidance
Alphabetical index entries that point to this code.
with septic shock R65.21
endotoxic R65.21
gram-negative R65.21
Clinical ClassificationClinical
AHRQ’s CCSR groups this code into broader clinical categories.
Clinical InformationClinical
Severe Sepsis
sepsis associated with organ dysfunction distant from the site of infection.
Patient EducationClinical
Sepsis
Sepsis is your body's overactive and extreme response to an infection. Sepsis is a life-threatening medical emergency. Without quick treatment, it can lead to tissue damage, organ failure, and even death.
The full article covers:
- What is sepsis?
- What causes sepsis?
- Who is more likely to develop sepsis?
- What are the symptoms of sepsis?
- What other problems can sepsis cause?
- How is sepsis diagnosed?
- What are the treatments for sepsis?
- Can sepsis be prevented?
Read the full article at MedlinePlus
Courtesy of MedlinePlus, a service of the U.S. National Library of Medicine.
Convert R65.21 to ICD-9-CMHistory
The closest ICD-9-CM equivalents under the General Equivalence Mappings.
Code HistoryHistory
Questions About R65.21Overview
What is the ICD-10 code for severe sepsis with septic shock?
The ICD-10-CM code for severe sepsis with septic shock is R65.21 (sometimes written as R6521). It is billable on HIPAA-covered claims from October 1, 2026 through September 30, 2027.
Is R65.21 (Severe sepsis) a billable code?
Yes. This is a billable ICD-10-CM code, specific enough to report severe sepsis with septic shock on HIPAA-covered claims from October 1, 2026 through September 30, 2027.
What MS-DRG does R65.21 group to?
On inpatient claims, severe sepsis with septic shock maps to MS-DRG 872, 871, 870, with relative weights from 1.0066 to 6.9432 depending on complications. Higher weights mean higher Medicare reimbursement.
Is R65.21 a CC or MCC?
CMS lists R65.21 as an MCC (major complication or comorbidity) for FY 2027. Reported as a secondary diagnosis, it places the inpatient stay in the highest-weighted DRG of its severity family. It does not count when the principal diagnosis is one of the 48 closely related codes in its exclusion list.
Can R65.21 be a principal diagnosis?
No. The Medicare Code Editor rejects this code as a principal diagnosis because severe sepsis with septic shock describes a circumstance that influences health status rather than a current illness. Report it as a secondary diagnosis.
What HCC is R65.21?
R65.21 (severe sepsis with septic shock) maps to CMS-HCC Category 2 (Septicemia, Sepsis, Systemic Inflammatory Response Syndrome/Shock), commonly written as HCC 2, in the CMS-HCC V28 model used for Medicare Advantage risk adjustment in payment year 2027. It mapped to HCC 2 under the retired V24 model. It also maps in the PACE (CMS-HCC V22), ESRD (V21), and ESRD (V24) models. It does not map to any RxHCC in the Part D prescription drug model.
Does R65.21 risk-adjust for Medicare Advantage payment?
Yes. When documented and reported on a Medicare Advantage encounter, R65.21 adds a risk adjustment factor of about 0.500 to the beneficiary's RAF score for a community, non-dual, aged enrollee (published V28 weights range from 0.447 to 0.780 depending on the payment segment). HCC 2 sits at the top of its hierarchy, so no other condition category supersedes it. See the full factor table on the HCC 2 category page.
