Oncology & Hematology Coding Alert

From a medical perspective, a patient who takes less of a prescribed cancer drug than their oncologist has prescribed presents a real problem.

What Are the Instructions for Using the Underdosing Codes?

Before assigning the appropriate underdosing code, you need to be aware of two instructions. The first is the Excludes1 note that states these codes exclude codes that describe any adverse reactions to prescription drugs that have been taken as directed and codes that describe poisoning or overdosing.

The second is “a sequencing note that tells you to ‘Code first underdosing of medication (T36-T50) with 5th or 6th character 6,’” advises Chelle Johnson, CPMA, CPC, CPCO, CPPM, CEMC, AAPC Fellow, billing/credentialing/auditing/ coding coordinator at County of Stanislaus Health Services Agency in Modesto, California.

Also, if the underdosing is due to the patient or caregiver experiencing “potential health hazards related to socioeconomic and psychosocial circumstances” per the language of ICD-10-CM, you should also code Z59.6 (Low income), Johnson advises.

Don’t make this mistake: In scenarios where the patient or the patient’s caregiver are responsible for the underdosing, you should never use Y63.6 (Underdosing and nonadministration of necessary drug, medicament or biological substance). This code indicates that it is the provider, not the patient or caregiver, who has either not administered a drug, or has not administered the correct amount of a drug, to a patient.

What Are the Upcoming Changes to Underdose Coding?

Up to now, ICD-10-CM guidelines have been vague about when you should use an underdosing code, but new wording for 2023 states that “documentation of a change in the patient’s condition is not required in order to assign an underdosing code. Documentation that the patient is taking less of a medication than is prescribed or discontinued the prescribed medication is sufficient for code assignment.”

So, the medical record simply needs to show the patient is not taking the prescribed dose of a medication, not that the underdosing is adversely affecting the patient’s condition.

ICD-10-CM 2023 also introduces new underdosing codes for use when the intentional or unintentional underdosing is due to a patient’s caregiver. When that happens, you’ll use the appropriate code from the following:

• Z91.A20 (Caregiver’s intentional underdosing of patient’s medication regimen due to financial hardship)
• Z91.A28 (Caregiver’s intentional underdosing of medication regimen for other reason)
• Z91.A3 (Caregiver’s unintentional underdosing of patient’s medication regimen)
• Z91.A4 (Caregiver’s other noncompliance with patient’s medication regimen)

Code This Underdosing Scenario

A provider prescribes Gleevec to a patient with chronic myeloid leukemia (CML). At a follow-up appointment, the patient confides in the doctor that they have recently lost their job and, with it, their health insurance. Consequently, the patient has been taking half the prescribed dose.

From a coding perspective, you’ll report the underdosing with the following codes:

• C92.10 (Chronic myeloid leukemia, BCR/ABL-positive, not having achieved remission) for the CML
• T45.1X6A (Underdosing of antineoplastic and immunosuppressive drugs, initial encounter) for the underdosing
• Z91.120 (Patient’s intentional underdosing of medication regimen due to financial hardship) for the underdosing due to financial hardship
• Z59.6 for the patient’s income status (if applicable)

Be Aware of E/M Implications

Not only do underdosing scenarios like this require you to use diagnosis codes such as the ones above, but they also require you to be aware of the impact they may have on the evaluation and management (E/M) service for the patient’s present condition.

This kind of scenario could well merit a lengthy additional E/M service, as “the provider will need to discuss the importance of medication compliance with the family, and they may also have to try to get help with medications,” says Donelle Holle, RN, president of Peds Coding Inc., and a healthcare, coding, and reimbursement consultant in Fort Wayne, Indiana.

For office/outpatient E/M services, this means coding +99417 (Prolonged office or other outpatient evaluation and management service(s) beyond the minimum required time of the primary procedure …) with one of the following:

• If the service reaches 75 minutes for a new patient visit: 99205 (Office or other outpatient visit for the evaluation and management of a new patient … 60-74 minutes of total time is spent on the date of the encounter)
• If the services reaches 55 minutes for an established patient: 99215 (Office or other outpatient visit for the evaluation and management of an established patient … 40-54 minutes of total time is spent on the date of the encounter)

For Medicare patients use G2212 (Prolonged office or other outpatient evaluation and management service(s) beyond the maximum required time of the primary procedure …) instead when the total time for visits hits 15 minutes beyond the maximum time range for 99205 (i.e., 89 minutes) and 99215 (i.e., 69 minutes).

Coding +99354/5 (Prolonged service(s) in the outpatient setting requiring direct patient contact beyond the time of the usual service …) could also be appropriate if the provider offers another time-based E/M service to the patient that is not 99205 or 99215, “and possibly 99358-+99359 (Prolonged evaluation and management service before and/or after direct patient care …) if the provider performs work related to the patient’s condition before or after the visit because of the complex nature of the scenario,” Holle suggests.