ICD code I50.30 – Unspecified diastolic heart failure

Key takeaways

ICD-10 Code I50.30 is billable for FY 2027, which runs from October 1, 2026 to September 30, 2027. Its parent code I50.3 is not billable and triggers a denial.

Use I50.30 only when physician documentation confirms diastolic heart failure but does not specify acuity (acute, chronic, or acute on chronic).

HFpEF (heart failure with preserved ejection fraction) codes to the I50.3x series, and I50.30 applies when acuity is undocumented.

Under CMS-HCC V28, I50.30 maps to HCC 226, while acute and acute on chronic diastolic heart failure map to HCCs of their own.

Pabau submits US claims through the Claim.MD clearinghouse and returns ERA denial codes, so billers can fix the cause of a rejection.

ICD-10 Code I50.30: Definition and billable status

ICD-10 Code I50.30 is the billable ICD-10-CM code for unspecified diastolic (congestive) heart failure, used when the physician documents diastolic heart failure without its acuity.

The code is valid for FY 2027, which covers discharges and encounters from October 1, 2026 through September 30, 2027. The CDC/NCHS ICD-10-CM web tool confirms its current billable status and official descriptor.

Clinical overview: Diastolic heart failure and HFpEF

Diastolic heart failure is a condition in which the left ventricle cannot relax and fill normally, even though the ejection fraction is preserved. On echocardiogram, that usually means an EF of 50% or above.

Clinically, it is the same condition as HFpEF (heart failure with preserved ejection fraction), which codes to the I50.3x series under CMS ICD-10-CM guidance.

The distinction from systolic heart failure decides the series. Systolic heart failure, with a reduced EF that is typically below 40%, maps to I50.2x, while diastolic maps to I50.3x.

Submitting I50.20 when the physician documented diastolic heart failure is a common error. It draws a medical necessity denial, because the record and the code describe different conditions.

• Preserved ejection fraction (HFpEF): EF 50% or above, impaired diastolic relaxation
• Key echo findings: Elevated E/e′ ratio, left atrial enlargement, diastolic function grading on Doppler
• Physician documentation trigger: The term “diastolic heart failure,” “HFpEF,” or “diastolic dysfunction with heart failure symptoms” must appear in provider notes
• Coding note: “CHF” alone does not specify diastolic or systolic, so it defaults to I50.9 (unspecified HF), not I50.30

I50.30 code hierarchy and parent category I50.3

I50.3 is the header category for all diastolic (congestive) heart failure codes. It is not billable. Only the four subcodes carry a valid claim submission designation, and each maps to a specific acuity scenario.

What “unspecified” means in ICD-10 Code I50.30

“Unspecified” in I50.30 refers to acuity, not to the type of heart failure. The physician has documented diastolic heart failure, so the type is settled.

The notes leave out whether the episode is acute, chronic, or acute on chronic. The ICD-10-CM Official Guidelines allow an unspecified code only when the documentation supports nothing more specific.

That makes I50.30 the last-resort code in the I50.3x series. When a coder sees “diastolic heart failure” in the notes with no acuity detail, the query workflow runs in four steps.

1. Check the full encounter record (H&P, discharge summary, progress notes) for acuity language: “acute,” “chronic,” “decompensated,” “stable,” “exacerbation.”
2. Check prior encounter records for a previously established acuity (a known chronic diastolic HF patient who presents acutely is coded I50.33).
3. If acuity is still unclear after record review, query the treating physician before defaulting to I50.30.
4. Assign I50.30 only when the physician query confirms acuity is not determinable or the physician does not respond within the facility’s CDI timeline.

AHA Coding Clinic guidance supports this order. When clinical indicators in the record point to a more specific code, the coder asks the physician before assigning an unspecified one.

Excludes notes, code-also instructions, and comorbid codes

The I50.3x category carries coding instructions that limit what can be submitted alongside I50.30. Ignoring them is a leading cause of Excludes1 edit denials.

• Excludes1 (cannot be coded together): Combined systolic and diastolic heart failure (I50.4x) cannot be reported with I50.30 on the same claim. If both systolic and diastolic failure are documented, use the I50.4x series only.
• Use additional code: Report the underlying cause where a causal relationship is established. Hypertensive heart disease with heart failure requires I11.0 (hypertensive heart disease with heart failure) coded before I50.30. I10 (essential hypertension) alongside I50.30 is incorrect.
• Code also: If heart failure is due to a cardiomyopathy, code the cardiomyopathy separately.

The table lists the comorbid conditions most often reported with I50.30. Inpatient sequencing follows the standard ICD-10-CM principal diagnosis conventions. In outpatient settings, the condition chiefly responsible for the visit leads.

How to document diastolic heart failure to avoid claim denials

Documentation failures cause more I50.30 denials than wrong code selection does. Coders who work in clinical documentation improvement (CDI) see the same omissions from one chart to the next.

Five documentation elements clear most I50.30 claims without a query.

1. Explicit diagnosis term: Physician must document “diastolic heart failure,” “diastolic (congestive) heart failure,” or “HFpEF,” never just “CHF” or “heart failure.”
2. Echocardiographic evidence: An echo report showing preserved EF (50%+) and diastolic dysfunction grading should be in the medical record for the encounter period.
3. Acuity absence is documented: If the physician query confirms acuity cannot be determined, record the query and response in the CDI record before assigning I50.30.
4. Causal relationship noted: When hypertension is present, the physician must state or clearly imply a causal relationship for I11.0 sequencing to apply.
5. Prior claim history reviewed: Check whether the patient’s previous encounters carry I50.32 or I50.33. If they do, that history supports a more specific code than I50.30 for the current visit.

The most common I50.30 denials, and the fix for each, are below.

When the same denial keeps returning, the fix belongs upstream. Our guide to denial management in healthcare covers that side, from ERA review to appeal.

Medicare and payer-specific requirements for I50.30

Under CMS-HCC V28, the risk adjustment model fully in effect for payment year 2026, I50.30 maps to HCC 226 (Heart Failure, Except End-Stage and Acute). V28 splits heart failure into separate HCCs by severity and acuity. End-stage heart failure sits in HCC 222, acute on chronic in HCC 224, and acute in HCC 225.

Acuity documentation therefore moves Medicare Advantage risk scores as well as claim accuracy. Check the CMS mapping file for your payment year before relying on any crosswalk.

• Inpatient (IPPS) coding: Follow UHDDS guidelines for principal diagnosis selection. I50.30 may be the principal diagnosis when diastolic HF is the condition chiefly responsible for the admission. Confirm it against the discharge summary.
• Outpatient coding: Per ICD-10-CM Section IV guidelines, code the condition to the highest degree of certainty. Avoid I50.30 on outpatient claims when the encounter note contains enough clinical detail to support I50.31, I50.32, or I50.33.
• Medicare annual wellness visits: HF diagnoses recaptured at an AWV follow the same code selection rule. Acuity must still be documented in the AWV encounter note, not inferred from the problem list.
• Local Coverage Determinations (LCDs): Check your Medicare Administrative Contractor (MAC) for heart-failure-specific LCDs that govern echocardiography or other services billed alongside I50.30.

Before a heart failure encounter, insurance eligibility verification confirms whether the patient has traditional Medicare or Medicare Advantage. That tells the practice whether HCC risk adjustment applies. When a claim comes back, the denial codes on the ERA identify which payer edit rejected it.

ICD-10 Code I50.30 vs I50.31, I50.32, and I50.33: Choosing the right code

Each code in the I50.3x series matches what the physician documents about acuity at the encounter. The chart below runs the decision in the order a coder meets it, with the type of heart failure first and acuity second.

The table adds the trigger phrases for each code and the mistake that most often sends a claim to the wrong one.

The AAPC ICD-10-CM lookup shows every Excludes note and code-also instruction for the I50.3x series in one view. For risk adjustment, the HCC ICD-10 Crosswalk maps I50.30 to its current-year HCC for Medicare Advantage encounters.

A clean claim for a diastolic HF encounter depends on getting the I50.3x selection right before the claim leaves the practice.

How claims management software keeps I50.30 claims clean

Much of the rework on heart failure claims starts after submission. A claim goes out with the unspecified code, the payer rejects it, and someone rebuilds the encounter from the chart weeks later.

Pabau, the practice management platform we build, keeps the encounter note and the claim in the same patient record. Its claims management software submits claims through the Claim.MD clearinghouse and checks eligibility before the visit. ERA remittances come back with their denial reason codes attached.

When an I50.30 claim is denied, the biller sees the reason code next to the note that produced it. The fix becomes a physician query or a corrected code, made once, so the same claim never goes out twice unchanged.

Manage heart failure claims without the rework

Pabau submits claims through Claim.MD, checks patient eligibility, and brings ERA denial codes back to the patient record. Catch I50.30 acuity, Excludes1 and sequencing problems before they turn into rework.

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Conclusion

I50.30 is a valid code, but it should be the rarest one in your diastolic heart failure claims. When it shows up often, the cause sits upstream in the note, where acuity goes unstated. Fix that documentation habit and the code mix corrects itself.

Under V28, acuity also decides the HCC. Acute and acute on chronic episodes land in categories of their own, so an unspecified code can misstate a Medicare Advantage patient’s risk.

Build the acuity question into your CDI queries and your revenue cycle management checks, so it is answered before the claim leaves the practice. Book a demo to see how Pabau links the encounter note, the claim and the remittance for heart failure billing.

Continue your research

Billing heart failure care to traditional Medicare? Medicare billing sets out how Medicare claims are built, submitted and paid.

Reading the remittance on a denied I50.30 claim? Electronic remittance advice explains what each part of an ERA tells your billing team.

Frequently asked questions