T50905A - Initial treatment for harmful side effects from an unknown medication or biological substance

International Classification of Diseases

Last updated: 10/3/2025

What is a ICD-10 Code?

ICD-10 (International Classification of Diseases, 10th Revision) codes are used to classify and code all diagnoses, symptoms, and procedures recorded in association with hospital care. These codes provide a standardized way to track health conditions and their treatment outcomes.

Detailed Description

This code is used when a patient experiences an adverse (harmful) reaction or side effect from a medication, drug, or biological substance, but the specific substance causing the reaction is not known or specified. The 'initial' designation means this is the first time the patient is receiving medical care for this particular adverse reaction. This could include situations where a patient has a bad reaction to a medication but it's unclear which one caused it, or when multiple medications were involved. The healthcare provider will focus on treating the symptoms and effects of the reaction while potentially investigating what caused it.

Additional Information

This is a diagnostic code used for billing and medical record keeping. The actual treatment and cost will depend on the severity of the adverse reaction and symptoms present. Patients should bring all medications and supplements to their appointment to help identify the potential cause.

Category

Adverse Drug Reactions

Medical Specialty

General Medicine/Emergency Medicine

Expected Costs

We expect this to normally be in the range of:

$150 - $500

This is an estimate based on typical billing patterns. Your actual cost may vary depending on your insurance coverage, provider location, and specific circumstances.

What's Required Before This

  • Patient experiencing symptoms from medication/substance
  • Unclear which specific medication caused the reaction

What to Expect After

  • Monitor for resolution of symptoms
  • Medication review and reconciliation
  • Possible allergy testing
  • Documentation of suspected substances to avoid

Why Understanding This Code Matters

On Your Medical Bill

This code appears on your medical bills to identify the specific service, procedure, drug, or medical diagnosis you received. Understanding what it means helps you verify you're being charged correctly and know what to expect.

For Your Health

Knowing what this code represents helps you understand your treatment plan, ask better questions during appointments, and track your healthcare journey more effectively.

Want This Level of Detail on All Your Claims?

Get detailed explanations for every medical code on your Medicare bills. Currently supporting Medicare only.