Mastering MDS Section I: Coding Active Diagnoses
Our recent Skilled Nursing Facility (SNF) Targeted Probe and Educate (TPE) review identified a trend regarding the improper coding of active diagnoses in Section I of the Minimum Data Set (MDS) without meeting the criteria outlined in the CMS Resident Assessment Instrument (RAI) User’s Manual.
When coding active diagnoses, ensure you adhere to the mandatory 2-step verification process for every diagnosis entered on the MDS.
The 2-Step Verification Process
According to the RAI Manual, a diagnosis can’t be coded on the MDS unless it meets the 2-step process within the look-back period.
Step 1: Physician-Documented Diagnosis
There must be specific documentation by a physician (or nurse practitioner, physician assistant, or clinical nurse specialist if allowed by state law) that the resident has the diagnosis within the last 60 days.
Step 2: Active vs. Inactive Within the Look-Back Period
Once a documented diagnosis exists, it must be determined if the condition is active during the 7-day look-back period (except for Item I2300 UTI, which doesn’t use the active 7-day look-back period).
What Makes a Diagnosis "Active"?
To satisfy Step 2, the medical record must show active treatment, interventions beyond expected monitoring practices, medication administration, etc. specifically addressing the coded MDS item during the 7-day look-back period:
- Medication Management: The resident receives a specific medication for the condition (e.g., Insulin for Diabetes, Lisinopril for Hypertension, Spiriva for COPD, Eliquis for CVA).
- Active Treatments: The resident is receiving therapies, wound care, or specialized interventions (e.g., physical therapy for an Osteoarthritis flare-up, speech therapy for Dysphagia).
- Interventions: The condition requires dietary modification and a high-calorie/high-protein supplement (e.g., Ensure, Med Pass and mechanically altered diet with fortified foods for Malnutrition (protein, calorie) or risk of malnutrition).
❌ Inactive vs. ✔️ Active: TPE Audit Scenarios
| Diagnosis | ❌ Inactive (Do Not Code) | ✔️ Active (Code on MDS) |
|---|---|---|
| Diabetes Mellitus (Section I2900) | Listed in the hospital history. The resident is on a regular diet, takes no diabetic medications, and has no blood sugar monitoring ordered or performed during the 7-day look-back period. | Resident receives daily antidiabetic medication (e.g., Metformin, Insulin), has scheduled fingerstick blood sugar monitoring (which included a sliding scale of insulin coverage) as physician ordered, and is on a physician ordered diabetic diet. |
| Asthma/COPD/ Chronic Lung Disease (Section I6200) | Resident has a history of Asthma but is currently on room air, has clear lung sounds, and has no respiratory medications or treatments scheduled or administered. | Resident receives scheduled pulmonary medications, routine oxygen therapy, or required maintenance or rescue inhalers during the look-back period (e.g., Albuterol, Symbicort), due to an abnormal respiratory assessment and complaints of shortness of breath during the 7-day look-back window. |
| CVA/TIA/Stroke (Section I4500) | Resident had a stroke 1 year ago. Has residual hemiparesis, but no new residual effects or related active therapies, no acute neurological symptoms, and CT findings were negative. | Resident has a history of CVA and is currently receiving physical and occupational therapy to treat hemiparesis resulting from the CVA. |
| Anemia (Section I0200) | Listed on the past medical history list, but no labs have been ordered, and no iron supplements or medications are prescribed. | Documented by the physician, and the resident is taking daily iron supplements or had a CBC drawn during the look-back period to monitor it. |
Best Practices to Prevent Future TPE Errors
- Scrutinize Section I: Active Diagnoses: Only code conditions here if they explicitly meet the 2-step criteria.
- Do Not Code "Resolved" Conditions: If a condition has cleared up (e.g., pneumonia that is completely resolved or an infection that has been fully treated), it is no longer active.
- Verify the Look-Back Window: Ensure the nursing notes, MARs, TARs, and therapy logs explicitly demonstrate active treatment, interventions or medication administered specific to the coded MDS items during the 7-day look-back period from the Assessment Reference Date (ARD).
Resources:
- CMS Resident Assessment Instrument (RAI) User’s Manual

- CMS Medicare Benefit Policy Manual (Pub. 100-02), Chapter 8
- Coverage of Extended Care (SNF) Services - CMS Medicare Claims Processing Manual (Pub. 100-04), Chapter 6
- SNF Inpatient Part A Billing and SNF Consolidated Billing
Published: 09.23.2026

