CMS Outpatient Intravenous Insulin Treatment Coverage Policy (NCD 334): What Billing Teams Need to Know

CMS updated National Coverage Determination (NCD) 334 covering Outpatient Intravenous Insulin Treatment (OIVIT), with a modified policy effective March 12, 2026. This NCD establishes a blanket national non-coverage determination for OIVIT under Medicare—meaning no claim submitted for services furnished as part of an OIVIT regimen will be reimbursed, regardless of diagnosis or clinical rationale. If your practice or facility has encountered patients seeking this therapy, understanding the precise scope of this policy is essential to preventing denials and potential compliance exposure.

What Is Outpatient Intravenous Insulin Treatment Under CMS NCD 334?

OIVIT refers to an outpatient regimen that integrates pulsatile or continuous intravenous infusion of insulin—delivered via any means—guided by measurement of one or more of the following: respiratory quotient, urine urea nitrogen (UUN), arterial/venous/capillary glucose, or potassium concentration. The therapy is performed in scheduled, recurring, periodic intermittent episodes.

This is not a single-session intervention. OIVIT is typically administered on an intermittent basis—often weekly—and is frequently performed chronically without duration limits. Glucose or other carbohydrate is made available to the patient ad libitum throughout the infusion.

What makes this policy particularly important for billing teams is the number of aliases this therapy goes by. CMS explicitly calls out the following as falling under the NCD 334 non-coverage umbrella:

• Cellular Activation Therapy (CAT)
• Chronic Intermittent Intravenous Insulin Therapy (CIIT)
• Hepatic Activation Therapy (HAT)
• Intercellular Activation Therapy (iCAT)
• Metabolic Activation Therapy (MAT)
• Pulsatile Intravenous Insulin Treatment (PIVIT)
• Pulse Insulin Therapy (PIT)
• Pulsatile Therapy (PT)

If a provider is ordering or a patient is seeking any of these therapies by name, NCD 334 applies—and Medicare will not cover it.

CMS Coverage Determination: Why OIVIT Is Nationally Non-Covered

The Centers for Medicare & Medicaid Services first made this non-coverage determination effective for claims with dates of service on and after December 23, 2009. The basis for non-coverage is clear: CMS determined that the evidence is adequate to conclude that OIVIT does not improve health outcomes in Medicare beneficiaries.

Under Section 1862(a)(1)(A) of the Social Security Act, Medicare only covers items and services that are reasonable and necessary for the diagnosis or treatment of illness or injury. CMS concluded that OIVIT fails this standard for any indication—there are no nationally covered indications listed under this NCD, and all services comprising an OIVIT regimen are nationally non-covered.

This is not a "coverage with evidence development" or investigational designation with a pathway to future coverage. It is a definitive non-coverage determination. Providers who continue to furnish OIVIT and bill Medicare for it face not only claim denials but potential fraud and abuse liability.

The Critical Carve-Out: When Individual Components May Still Be Covered

This is where billing teams must pay close attention. CMS explicitly acknowledges that individual components of an OIVIT regimen—IV insulin administration, glucose monitoring, laboratory testing—may have legitimate medical uses in conventional treatment regimens for diabetes and other conditions.

Coverage for those individual components is governed by other NCDs and local coverage determinations, not NCD 334. CMS cross-references several relevant policies:

• NCD 40.2 — Home Blood Glucose Monitors
• NCD 40.3 — Closed-loop Blood Glucose Control Devices (CBGCD)
• NCD 190.20 — Blood Glucose Testing
• NCD 280.14 — Infusion Pumps
• Claims Processing Manual, Chapter 18, Section 90 — Diabetes Screening

The governing principle: if a service is being furnished as part of an OIVIT regimen, NCD 334 non-coverage applies. If that same service—say, blood glucose testing or insulin infusion—is being furnished as part of a conventional, medically necessary treatment regimen, coverage may apply under the appropriate NCD or LCD.

The documentation burden falls on the provider to establish that the service is not part of an OIVIT regimen. This distinction must be crystal clear in the medical record and on the claim.

Affected Codes

The policy data for NCD 334 does not list specific CPT or HCPCS codes associated with this determination. This is consistent with how CMS structured this NCD—the non-coverage applies to the regimen as a whole, rather than to discrete procedure codes. Any code submitted in the context of an OIVIT regimen is subject to denial under this policy.

For billing purposes, claims processing instructions are addressed in CMS Transmittals TN 1913 and TN 1923 (Medicare Claims Processing). Your Medicare Administrative Contractor (MAC) may publish additional local guidance on how to flag or deny OIVIT-related claims.

If you believe a service was incorrectly denied under NCD 334—for example, a standalone IV insulin administration that is part of a conventional inpatient or outpatient diabetes management protocol—appeals should document clearly that the service was not furnished as part of an OIVIT regimen as defined in Section A of this NCD.

What Your Billing Team Should Do