Each month, IBC features an example of how ICD-9 codes will translate to ICD-10
codes. We will present coding examples from different specialties and popular
disease categories to demonstrate the granularity that the new ICD-10 code set
will provide.
Coding convention: New clinical concept in occurrence of
drug toxicity (drug underdosing)
The coding examples will demonstrate the new clinical concept of drug
underdosing conveyed in ICD-10.
Drug underdosing is a new clinical terminology in ICD-10. ICD-10 contains codes
for underdosing, whereas ICD-9 does not. This term identifies situations in
which a patient has taken less of a medication than prescribed by their
physician or less than instructed by the manufacturer, whether inadvertently or
deliberately.
For underdosing, assign the code from categories T36 – T50 found in
Chapter 19. These codes require a 7th character extension to describe an
initial encounter (A), subsequent encounter (D), or sequela encounter (S).
Underdosing codes must be identified in the following order:
The medical condition is sequenced first. The first-listed code would be the
event that is triggered or prolonged due to this circumstance.
The underdosing code is listed as the secondary code assignment. Codes for
underdosing should never be assigned as principal or first-listed codes.
The additional code explains why the patient is not taking the medication(s).
Financial hardships and age-related debilities are some examples of underdosing.
Example A
A patient is prescribed the antibiotic tetracycline to treat a UTI (urinary
tract infection). The patient did not take the medication as prescribed, which
resulted in pyelonephritis (kidney infection).
ICD-10 Code
Narrative
Coding sequence
N10
Acute tubulo-interstitial nephritis
The first-listed code would be the event that is triggered or prolonged due to
this circumstance.
T36.4x6A
Underdosing of tetracyclines, initial encounter
The underdosing code would be the secondary code assignment.
Example B
A patient is prescribed prednisone for rheumatoid arthritis and has been taking
it long-term. The patient abruptly stopped taking the medication, which
resulted in secondary adrenal insufficiency. The patient is aware of the risk
of not being weaned from steroidal drugs but could not afford to pay for the
medication.
ICD-10 Code
Narrative
Coding sequence
E27.40
Unspecified adrenocortical insufficiency
The first-listed code would be the event that is triggered or prolonged due to
this circumstance.
T38.0x6
Underdosing of glucocorticoids and synthetic analogues
The underdosing code would be the secondary code
assignment.
Z91.120
Patient's intentional underdosing of medication regimen due to financial
hardship
The additional code explains why the patient is not taking the medication(s).
Note: In this scenario, E27.3 (drug-induced adrenocortical insufficiency) would
not be appropriate, as the condition is not drug-induced but is directly
attributed to the abrupt discontinuation of the medication.
A complete list of all ICD-10 coding examples featured to date can be found
here:
>>
ICD-10 Spotlight: Know the codes booklet
For additional information related to the IBC transition to ICD-10, please
visit the
ICD-10 section
of our website.