2024 ICD-10-CM Diagnosis Code T46.4X6A

Underdosing of angiotensin-converting-enzyme inhibitors, initial encounter

ICD-10-CM Code:
T46.4X6A
ICD-10 Code for:
Underdosing of angiotens-convert-enzyme inhibitors, init
Is Billable?
Yes - Valid for Submission
Chronic Condition Indicator: [1]
Not chronic
Code Navigator:

Code Classification

  • Injury, poisoning and certain other consequences of external causes
    (S00–T88)
    • Poisoning by, adverse effect of and underdosing of drugs, medicaments and biological substances
      (T36-T50)
      • Poisoning by, adverse effect of and underdosing of agents primarily affecting the cardiovascular system
        (T46)

T46.4X6A is a billable diagnosis code used to specify a medical diagnosis of underdosing of angiotensin-converting-enzyme inhibitors, initial encounter. The code is valid during the current fiscal year for the submission of HIPAA-covered transactions from October 01, 2023 through September 30, 2024.

This code describes a circumstance which influences the patient's health status but not a current illness or injury. The code is unacceptable as a principal diagnosis.

T46.4X6A is an initial encounter code, includes a 7th character and should be used while the patient is receiving active treatment for a condition like underdosing of angiotensin-converting-enzyme inhibitors. According to ICD-10-CM Guidelines an "initial encounter" doesn't necessarily means "initial visit". The 7th character should be used when the patient is undergoing active treatment regardless if new or different providers saw the patient over the course of a treatment. The appropriate 7th character codes should also be used even if the patient delayed seeking treatment for a condition.

Clinical Classification

Clinical Information

  • Captopril

    a potent and specific inhibitor of peptidyl-dipeptidase a. it blocks the conversion of angiotensin i to angiotensin ii, a vasoconstrictor and important regulator of arterial blood pressure. captopril acts to suppress the renin-angiotensin system and inhibits pressure responses to exogenous angiotensin.
  • Cilazapril

    one of the angiotensin-converting enzyme inhibitors (ace inhibitors) used for hypertension. it is a prodrug that is hydrolyzed after absorption to its main metabolite cilazaprilat.
  • Enalapril

    an angiotensin-converting enzyme inhibitor that is used to treat hypertension and heart failure.
  • Enalaprilat

    the active metabolite of enalapril and one of the potent, intravenously administered, angiotensin-converting enzyme inhibitors. it is an effective agent for the treatment of essential hypertension and has beneficial hemodynamic effects in heart failure. the drug produces renal vasodilation with an increase in sodium excretion.
  • Fosinopril

    a phosphinic acid-containing angiotensin-converting enzyme inhibitor that is effective in the treatment of hypertension. it is a prodrug that is converted to its active metabolite fosinoprilat.
  • Lisinopril

    one of the angiotensin-converting enzyme inhibitors (ace inhibitors), orally active, that has been used in the treatment of hypertension and congestive heart failure.
  • Perindopril

    an angiotensin-converting enzyme inhibitor. it is used in patients with hypertension and heart failure.
  • Quinapril

    a tetrahydroisoquinoline derivative and angiotensin converting enzyme inhibitor that is used in the treatment of hypertension and heart failure.
  • Ramipril

    a long-acting angiotensin-converting enzyme inhibitor. it is a prodrug that is transformed in the liver to its active metabolite ramiprilat.

Coding Guidelines

Underdosing refers to taking less of a medication than is prescribed by a provider or a manufacturer's instruction. Codes for underdosing should never be assigned as principal or first-listed codes. If a patient has a relapse or exacerbation of the medical condition for which the drug is prescribed because of the reduction in dose, then the medical condition itself should be coded.

The appropriate 7th character is to be added to each code from block Poisoning by, adverse effect of and underdosing of agents primarily affecting the cardiovascular system (T46). Use the following options for the aplicable episode of care:

  • A - initial encounter
  • D - subsequent encounter
  • S - sequela

Code Edits

The Medicare Code Editor (MCE) detects and reports errors in the coding of claims data. The following ICD-10-CM Code Edits are applicable to this code:

  • Unacceptable principal diagnosis - There are selected codes that describe a circumstance which influences an individual's health status but not a current illness or injury, or codes that are not specific manifestations but may be due to an underlying cause. These codes are considered unacceptable as a principal diagnosis.

Convert T46.4X6A to ICD-9-CM

  • ICD-9-CM Code: -
    No Map Flag -

Table of Drugs and Chemicals

The parent code T46.4X6 of the current diagnosis code is referenced in the Table of Drugs and Chemicals, this table contains a classification of drugs, industrial solvents, corrosive gases, noxious plants, pesticides, and other toxic agents.

According to ICD-10-CM coding guidelines it is advised to do not code directly from the Table of Drugs and Chemicals, instead always refer back to the Tabular List when doing the initial coding. Each substance in the table is assigned a code according to the poisoning classification and external causes of adverse effects. It is important to use as many codes as necessary to specify all reported drugs, medicinal or chemical substances. If the same diagnosis code describes the causative agent for more than one adverse reaction, poisoning, toxic effect or underdosing, utilize the code only once.

Substance Poisoning
Accidental
(unintentional)
Poisoning
Accidental
(self-harm)
Poisoning
Assault
Poisoning
Undetermined
Adverse
effect
Underdosing
AlaceprilT46.4X1T46.4X2T46.4X3T46.4X4T46.4X5T46.4X6
BenazeprilT46.4X1T46.4X2T46.4X3T46.4X4T46.4X5T46.4X6
CaptoprilT46.4X1T46.4X2T46.4X3T46.4X4T46.4X5T46.4X6
CilazaprilT46.4X1T46.4X2T46.4X3T46.4X4T46.4X5T46.4X6
EnalaprilT46.4X1T46.4X2T46.4X3T46.4X4T46.4X5T46.4X6
EnalaprilatT46.4X1T46.4X2T46.4X3T46.4X4T46.4X5T46.4X6
FosinoprilT46.4X1T46.4X2T46.4X3T46.4X4T46.4X5T46.4X6
Fosinopril
  »sodium
T46.4X1T46.4X2T46.4X3T46.4X4T46.4X5T46.4X6
InhibitorT46.4X1T46.4X2T46.4X3T46.4X4T46.4X5T46.4X6
Inhibitor
  »angiotensin-converting enzyme
T46.4X1T46.4X2T46.4X3T46.4X4T46.4X5T46.4X6
Inhibitor
  »carbonic anhydrase
T46.4X1T46.4X2T46.4X3T46.4X4T46.4X5T46.4X6
Inhibitor
  »fibrinolysis
T46.4X1T46.4X2T46.4X3T46.4X4T46.4X5T46.4X6
Inhibitor
  »monoamine oxidase NEC
T46.4X1T46.4X2T46.4X3T46.4X4T46.4X5T46.4X6
Inhibitor
  »monoamine oxidase NEC
    »hydrazine
T46.4X1T46.4X2T46.4X3T46.4X4T46.4X5T46.4X6
Inhibitor
  »postsynaptic
T46.4X1T46.4X2T46.4X3T46.4X4T46.4X5T46.4X6
Inhibitor
  »prothrombin synthesis
T46.4X1T46.4X2T46.4X3T46.4X4T46.4X5T46.4X6
LisinoprilT46.4X1T46.4X2T46.4X3T46.4X4T46.4X5T46.4X6
PerindoprilT46.4X1T46.4X2T46.4X3T46.4X4T46.4X5T46.4X6
QuinaprilT46.4X1T46.4X2T46.4X3T46.4X4T46.4X5T46.4X6
RamiprilT46.4X1T46.4X2T46.4X3T46.4X4T46.4X5T46.4X6
SpiraprilT46.4X1T46.4X2T46.4X3T46.4X4T46.4X5T46.4X6
ZofenoprilT46.4X1T46.4X2T46.4X3T46.4X4T46.4X5T46.4X6

Patient Education


Medication Errors

Medicines treat infectious diseases, prevent problems from chronic diseases, and ease pain. But medicines can also cause harmful reactions if not used correctly. Errors can happen in the hospital, at the health care provider's office, at the pharmacy, or at home. You can help prevent errors by:

  • Knowing your medicines. When you get a prescription, ask the name of the medicine and check to make sure that the pharmacy gave you the right medicine. Make sure that you understand how often you should take the medicine and how long you should take it.
  • Keeping a list of medicines.
    • Write down all of the medicines that you are taking, including the names of your medicines, how much you take, and when you take them. Make sure to include any over-the-counter medicines, vitamins, supplements, and herbs that you take.
    • List the medicines that you are allergic to or that have caused you problems in the past.
    • Take this list with you every time you see a health care provider.
  • Reading medicine labels and following the directions. Don't just rely on your memory - read the medication label every time. Be especially careful when giving medicines to children.
  • Asking questions. If you don't know the answers to these questions, ask your health care provider or pharmacist:
    • Why am I taking this medicine?
    • What are the common side effects?
    • What should I do if I have side effects?
    • When should I stop this medicine?
    • Can I take this medicine with the other medicines and supplements on my list?
    • Do I need to avoid certain foods or alcohol while taking this medicine?

Food and Drug Administration


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Code History

  • FY 2024 - No Change, effective from 10/1/2023 through 9/30/2024
  • FY 2023 - No Change, effective from 10/1/2022 through 9/30/2023
  • FY 2022 - No Change, effective from 10/1/2021 through 9/30/2022
  • FY 2021 - No Change, effective from 10/1/2020 through 9/30/2021
  • FY 2020 - No Change, effective from 10/1/2019 through 9/30/2020
  • FY 2019 - No Change, effective from 10/1/2018 through 9/30/2019
  • FY 2018 - No Change, effective from 10/1/2017 through 9/30/2018
  • FY 2017 - No Change, effective from 10/1/2016 through 9/30/2017
  • FY 2016 - New Code, effective from 10/1/2015 through 9/30/2016. This was the first year ICD-10-CM was implemented into the HIPAA code set.

Footnotes

[1] Not chronic - A diagnosis code that does not fit the criteria for chronic condition (duration, ongoing medical treatment, and limitations) is considered not chronic. Some codes designated as not chronic are acute conditions. Other diagnosis codes that indicate a possible chronic condition, but for which the duration of the illness is not specified in the code description (i.e., we do not know the condition has lasted 12 months or longer) also are considered not chronic.