2026 ICD-10-CM Diagnosis Code T39.8X6AUnderdosing of other nonopioid analgesics and antipyretics, not elsewhere classified, initial encounter
T39.8X6A is a billable ICD-10-CM diagnosis code for underdosing of other nonopioid analgesics and antipyretics, not elsewhere classified, initial encounter. The 7th character A marks it as an initial encounter code, used while the patient is receiving active treatment. It is valid on HIPAA claims for fiscal year 2026 (October 1, 2025 through September 30, 2026). The code is not accepted as a principal diagnosis by the Medicare Code Editor. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Underdosing of drugs and medicaments, initial encounter.
Code Identity
Code Classification
Code EditsBilling
Medicare Code Editor checks that affect claim validity for T39.8X6A.
Coding GuidelinesGuidance
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 nonopioid analgesics, antipyretics and antirheumatics (T39). 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 2026, published by CMS and the National Center for Health Statistics.
Clinical ClassificationClinical
AHRQ’s CCSR groups this code into broader clinical categories.
Clinical InformationClinical
Clonixin
anti-inflammatory analgesic.Glafenine
an anthranilic acid derivative with analgesic properties used for the relief of all types of pain.Jamaica
an island in the greater antilles in the west indies. its capital is kingston. it was discovered in 1494 by columbus and was a spanish colony 1509-1655 until captured by the english. its flourishing slave trade was abolished in the 19th century. it was a british colony 1655-1958 and a territory of the west indies federation 1958-62. it achieved full independence in 1962. the name is from the arawak xaymaca, rich in springs or land of springs. (from webster's new geographical dictionary, 1988, p564 & room, brewer's dictionary of names, 1992, p267)Smilax
a plant genus of the family smilacaceae. members contain smiglasides (phenylpropanoid glycosides) and steroidal saponins. commercially it is sometimes adulterated with hemidesmus, which would affect experimental results. drinks called sarsaparilla and root beer have been prepared from the smilaz ornata (jamaican sarsaparilla) and sassafras.Ketorolac
a pyrrolizine carboxylic acid derivative structurally related to indomethacin. it is an nsaid and is used principally for its analgesic activity. (from martindale the extra pharmacopoeia, 31st ed)Ketorolac Tromethamine
a pyrrolizine carboxylic acid derivative structurally related to indomethacin. it is a non-steroidal anti-inflammatory agent used for analgesia for postoperative pain and inhibits cyclooxygenase activity.Meptazinol
a narcotic antagonist with analgesic properties. it is used for the control of moderate to severe pain.Nefopam
non-narcotic analgesic chemically similar to orphenadrine. its mechanism of action is unclear. it is used for the relief of acute and chronic pain. (from martindale, the extra pharmacopoeia, 30th ed, p26)Phenazopyridine
a local anesthetic that has been used in urinary tract disorders. its use is limited by problems with toxicity (primarily blood disorders) and potential carcinogenicity.Sumatriptan
a serotonin agonist that acts selectively at 5ht1 receptors. it is used in the treatment of migraine disorders.
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
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:
Read the full article at MedlinePlus
Courtesy of MedlinePlus, a service of the U.S. National Library of Medicine.
Convert T39.8X6A to ICD-9-CMHistory
Code HistoryHistory
Questions About T39.8X6AOverview
Is T39.8X6A a billable code?
Yes. This is a billable ICD-10-CM code, specific enough to report underdosing of other nonopioid analgesics and antipyretics, not elsewhere classified, initial encounter on HIPAA-covered claims from October 1, 2025 through September 30, 2026.
What does the 7th character A in T39.8X6A mean?
The final character A marks the initial encounter: use it while the patient is receiving active treatment for underdosing of other nonopioid analgesics and antipyretics, not elsewhere classified, such as an emergency visit or first evaluation.
Can T39.8X6A be a principal diagnosis?
No. The Medicare Code Editor rejects this code as a principal diagnosis because underdosing of other nonopioid analgesics and antipyretics, not elsewhere classified, initial encounter describes a circumstance that influences health status rather than a current illness. Report it as a secondary diagnosis.
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.
