2027 ICD-10-CM Diagnosis Code T45.2X5SAdverse effect of vitamins, sequela
T45.2X5S is a billable ICD-10-CM diagnosis code for adverse effect of vitamins, sequela. The 7th character S marks it as a sequela code, which reports a problem that remains after the original condition has resolved. It is valid on HIPAA claims for fiscal year 2027 (October 1, 2026 through September 30, 2027) and groups to MS-DRG 922 through 923. The code is not accepted as a principal diagnosis by the Medicare Code Editor and exempt from POA reporting. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Poisoning/toxic effect/adverse effects/underdosing, sequela.
Code Identity
Code Classification
Code EditsBilling
Medicare Code Editor checks that affect claim validity for T45.2X5S.
Present on Admission (POA)Billing
T45.2X5S is exempt from POA reporting on inpatient claims to general acute care hospitals. Review the other POA exempt codes in Poisoning by, adverse effect of and underdosing of drugs, medicaments and biological substances (T36-T50).
Approximate SynonymsGuidance
Alternate terms and clinical phrases that map to this code.
- Adverse reaction to oil
- Adverse reaction to vitamin B and/or vitamin B derivative
- Adverse reaction to vitamin D and/or vitamin D derivative
- Alpha-tocopheryl adverse reaction
- Ascorbic acid adverse reaction
- Calcipotriol adverse reaction
- Fat soluble vitamin adverse reaction
- Fish oils adverse reaction
- Hypercalcemia caused by thiazide and/or retinol
- Intravenous nutrition adverse reaction
- L-Carnitine adverse reaction
- Multivitamin and mineral preparations adverse reaction
- Niacinamide adverse reaction
- Nicotinic acid adverse reaction
- Omega 3-marine triglycerides adverse reaction
- Pyridoxine preparation adverse reaction
- Reticulocyte count outside reference range
- Reticulocytosis
- Reticulocytosis after B12
- Retinoid adverse reaction
- Retinoid dermatitis
- Terpenes adverse reaction
- Thiamine preparation adverse reaction
- Vitamin A adverse reaction
- Vitamin B12 preparation adverse reaction
- Vitamin products adverse reaction
- Water soluble vitamin adverse reaction
Coding GuidelinesGuidance
When coding an adverse effect of a drug that has been correctly prescribed and properly administered, assign the appropriate code for the nature of the adverse effect followed by the appropriate code for the adverse effect of the drug.
The appropriate 7th character is to be added to each code from block Poisoning by, adverse effect of and underdosing of primarily systemic and hematological agents, not elsewhere classified (T45). Use the following options for the applicable episode of care:
- A - initial encounter
- D - subsequent encounter
- S - sequela
Source: ICD-10-CM Official Guidelines for Coding and Reporting, FY 2027, published by CMS and the National Center for Health Statistics.
Instructional NotesGuidance
Instructions from the official ICD-10-CM Tabular List that apply to T45.2X5S: its own notes plus those printed at T45.2, T45, block T36-T50, and Chapter 19. A note printed at a category, block or chapter applies to every code under it.
Includes
Further defines, or gives examples of, the content of the category.
- adverse effect of correct substance properly administered
- poisoning by overdose of substance
- poisoning by wrong substance given or taken in error
- underdosing by (inadvertently) (deliberately) taking less substance than prescribed or instructed
Excludes1
Not coded here: the excluded code is never reported together with this one, unless the two conditions are unrelated.
- toxic reaction to local anesthesia in pregnancy (O29.3-)
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.
Use Additional Code
Add a second code, after this one, to fully describe the condition.
- code to identify any retained foreign body, if applicable (Z18.-)
Notes
General instructions on how these codes are used.
- Use secondary code(s) from Chapter 20, External causes of morbidity, to indicate cause of injury. Codes within the T section that include the external cause do not require an additional external cause code
- The chapter uses the S-section for coding different types of injuries related to single body regions and the T-section to cover injuries to unspecified body regions as well as poisoning and certain other consequences of external causes.
7th Character
Every code in the category takes a 7th character from the listed values, with the placeholder X filling any empty positions before it.
- The appropriate 7th character is to be added to each code from category T45
- Ainitial encounter
- Dsubsequent encounter
- Ssequela this code
Source: CMS ICD-10-CM Tabular List. How to read instructional notes.
Clinical ClassificationClinical
AHRQ’s CCSR groups this code into broader clinical categories.
Table of Drugs and ChemicalsClinical
Substances in the Table of Drugs and Chemicals that reference this code family. Always confirm in the Tabular List before coding.
Patient EducationClinical
Drug Reactions
Most of the time, medicines make our lives better. They reduce aches and pains, fight infections, and control problems such as high blood pressure or diabetes. But medicines can also cause unwanted reactions, such as drug interactions, side effects, and allergies.
The full article covers:
- What is a drug interaction?
- What are side effects?
- What are drug allergies?
- How can I stay safe when taking medicines?
Read the full article at MedlinePlus
Courtesy of MedlinePlus, a service of the U.S. National Library of Medicine.
Convert T45.2X5S to ICD-9-CMHistory
The closest ICD-9-CM equivalents under the General Equivalence Mappings.
Code HistoryHistory
Questions About T45.2X5SOverview
What is the ICD-10 code for adverse effect of vitamins, sequela?
The ICD-10-CM code for adverse effect of vitamins, sequela is T45.2X5S (sometimes written as T452X5S). It is billable on HIPAA-covered claims from October 1, 2026 through September 30, 2027.
Is T45.2X5S (Adverse effect of vitamins) a billable code?
Yes. This is a billable ICD-10-CM code, specific enough to report adverse effect of vitamins, sequela on HIPAA-covered claims from October 1, 2026 through September 30, 2027.
What does the 7th character S in T45.2X5S mean?
The final character S makes this a sequela code: it reports a lingering problem that remains after the adverse effect of vitamins itself has resolved, not the original event.
What MS-DRG does T45.2X5S group to?
On inpatient claims, adverse effect of vitamins, sequela maps to MS-DRG 923, 922, with relative weights from 0.9980 to 1.6248 depending on complications. Higher weights mean higher Medicare reimbursement.
Can T45.2X5S be a principal diagnosis?
No. The Medicare Code Editor rejects this code as a principal diagnosis because adverse effect of vitamins, sequela describes a circumstance that influences health status rather than a current illness. Report it as a secondary diagnosis.
