K52.21 — Food protein-induced enterocolitis syndrome
Is K52.21 billable?
Yes — K52.21 is billable for FY2027. K52.21 is a valid, billable ICD-10-CM code at the highest level of specificity in its branch. K52.21 may be submitted for encounters from October 1, 2026 through September 30, 2027.
K52.21 at a glance
| Code | K52.21 |
|---|---|
| Description | Food protein-induced enterocolitis syndrome |
| Billable | Yes |
| Code set | ICD-10-CM FY2027 |
| Valid for encounters | October 1, 2026 – September 30, 2027 |
Which MS-DRGs does K52.21 group to?
K52.21 sits in MDC 06 and helps define the logic of 2 MS-DRGs (version 44, FY2027). Which one a stay actually groups to also depends on procedures and secondary diagnoses.
- 391Esophagitis, Gastroenteritis and Miscellaneous Digestive Disorders with MCCmedical
- 392Esophagitis, Gastroenteritis and Miscellaneous Digestive Disorders without MCCmedical
How is K52.21 listed in the Alphabetic Index?
These are the routes through the Alphabetic Index that lead to K52.21. They show the wording a clinician may have documented, which often differs from the Tabular description.
- FPIES (food protein-induced enterocolitis syndrome)
- Syndrome › food protein-induced enterocolitis
- Allergy, allergic › milk protein › enterocolitis syndrome (reaction) (to)
- Colitis › allergic › with › food protein-induced enterocolitis syndrome (acute) (catarrhal) (chronic) (noninfective) (hemorrhagic)
- Enteritis › allergic › with › food protein-induced enterocolitis syndrome (acute) (diarrheal) (hemorrhagic) (noninfective)
- Enteritis › allergic › with › FPIES (acute) (diarrheal) (hemorrhagic) (noninfective)
- Gastroenteritis › allergic › with › food protein-induced enterocolitis syndrome (acute) (chronic) (noninfectious)
Use additional code
Report an additional code alongside K52.21 to fully describe the condition. K52.21 is sequenced first.
- code for hypovolemic shock, if present (R57.1)
Inclusion terms
Alternative wording in documentation that is classified to K52.21.
- FPIES
Excludes1 — never code together — inherited from K50-K52
The conditions below can never be reported together with K52.21 on the same claim. An Excludes1 note means the two conditions cannot occur in the same patient, so reporting both is a coding error.
Use additional code — inherited from K52.2
Report an additional code alongside K52.21 to fully describe the condition. K52.21 is sequenced first.
Excludes2 — not included here — inherited from Chapter 11
The conditions below are not part of K52.21, but a patient may have both at the same time. When documentation supports it, K52.21 and the excluded code may both be reported.
- certain conditions originating in the perinatal period (P04-P96)
- certain infectious and parasitic diseases (A00-B99)
- complications of pregnancy, childbirth and the puerperium (O00-O9A)
- congenital malformations, deformations and chromosomal abnormalities (Q00-Q99)
- endocrine, nutritional and metabolic diseases (E00-E88)
- injury, poisoning and certain other consequences of external causes (S00-T88)
- neoplasms (C00-D49)
- symptoms, signs and abnormal clinical and laboratory findings, not elsewhere classified (R00-R94)
Excludes2 — not included here — inherited from K52.2
The conditions below are not part of K52.21, but a patient may have both at the same time. When documentation supports it, K52.21 and the excluded code may both be reported.
How long has K52.21 existed?
K52.21 first appears in FY2018 (FY2017 is not available, so it may have appeared then).
Derived from the official order files for FY2016–FY2026. FY2017 and FY2020 publish no order file, so those years are not covered.