MS-DRG 916 – Allergic Reactions without MCC
A Medical DRG in MDC 21 (Injuries, Poisonings & Toxic Effects of Drugs). Inpatient cases group to DRG 916 when the ICD-10-CM principal diagnosis is one of the 25 codes listed below and no secondary diagnosis on the MCC list is present. Its FY 2026 relative weight is 0.6663 with a geometric mean length of stay of 1.8 days.
Severity family
The grouper first assigns the case to MDC 21 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 → 915; without MCC → 916.
Principal Diagnosis Codes 25 codes · 3 categories
T78 Adverse effects, not elsewhere classified18 codes
- T78.00XA Anaphylactic reaction due to unspecified food, initial encounter
- T78.01XA Anaphylactic reaction due to peanuts, initial encounter
- T78.02XA Anaphylactic reaction due to shellfish (crustaceans), initial encounter
- T78.03XA Anaphylactic reaction due to other fish, initial encounter
- T78.04XA Anaphylactic reaction due to fruits and vegetables, initial encounter
- T78.05XA Anaphylactic reaction due to tree nuts and seeds, initial encounter
- T78.06XA Anaphylactic reaction due to food additives, initial encounter
- T78.070A Anaphylactic reaction due to milk and dairy products with tolerance to baked milk, initial encounter
- T78.071A Anaphylactic reaction due to milk and dairy products with reactivity to baked milk, initial encounter
- T78.079A Anaphylactic reaction due to milk and dairy products, unspecified, initial encounter
- T78.080A Anaphylactic reaction due to egg with tolerance to baked egg, initial encounter
- T78.081A Anaphylactic reaction due to egg with reactivity to baked egg, initial encounter
- T78.089A Anaphylactic reaction due to eggs, unspecified, initial encounter
- T78.09XA Anaphylactic reaction due to other food products, initial encounter
- T78.2XXA Anaphylactic shock, unspecified, initial encounter
- T78.3XXA Angioneurotic edema, initial encounter
- T78.40XA Allergy, unspecified, initial encounter
- T78.49XA Other allergy, initial encounter
T80 Complications following infusion, transfusion and therapeutic injection6 codes
- T80.51XA Anaphylactic reaction due to administration of blood and blood products, initial encounter
- T80.52XA Anaphylactic reaction due to vaccination, initial encounter
- T80.59XA Anaphylactic reaction due to other serum, initial encounter
- T80.61XA Other serum reaction due to administration of blood and blood products, initial encounter
- T80.62XA Other serum reaction due to vaccination, initial encounter
- T80.69XA Other serum reaction due to other serum, initial encounter
T88 Other complications of surgical and medical care, not elsewhere classified1 code
- T88.6XXA Anaphylactic reaction due to adverse effect of correct drug or medicament properly administered, initial encounter
Procedure Codes
Frequently Asked Questions
What is MS-DRG 916?
MS-DRG 916 (Allergic Reactions without MCC) is a medical DRG in MDC 21 (Injuries, Poisonings & Toxic Effects of Drugs). Its FY 2026 relative weight is 0.6663 with a geometric mean length of stay of 1.8 days.
What is the difference between DRG 915, 916?
All 2 share the same base category; the severity of secondary diagnoses separates them: 915 (with MCC), 916 (without 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 916?
25 ICD-10-CM principal diagnosis codes group to this DRG, spanning 3 three-character categories.
What is the relative weight of DRG 916?
The FY 2026 relative weight of this DRG is 0.6663, meaning reimbursement of roughly 0.67 times the average Medicare inpatient case. Multiply by a hospital's blended base rate for the approximate payment.
