Fecal Occult Blood Test — NCD 167 | CMS Coverage Update

TL;DR: The Centers for Medicare & Medicaid Services modified NCD 167, the CMS fecal occult blood test coverage policy, effective March 7, 2026. Here's what billing teams need to know.

CMS fecal occult blood test coverage policy under NCD 167 in the CMS system governs when Medicare pays for FOBT across three distinct test types: guaiac-based, immunoassay, and heme-porphyrin. The modification touches indications, frequency limitations, and the line between diagnostic and screening use — a distinction that drives reimbursement and determines which HCPCS code your team should report. This policy does not list specific CPT or HCPCS codes in the current version data, but the clinical and billing criteria are detailed enough to create real exposure if your team isn't aligned.

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Quick-Reference Table

Field	Detail Copy
Payer	CMS (Centers for Medicare & Medicaid Services)
Policy	Fecal Occult Blood Test
Policy Code	NCD 167
Change Type	Modified
Effective Date	2026-03-07
Impact Level	Medium
Specialties Affected	Gastroenterology, Primary Care, Internal Medicine, Laboratory Billing
Key Action	Audit your charge capture and documentation to confirm the correct indication — diagnostic vs. screening — is driving every FOBT claim before March 7, 2026

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CMS Fecal Occult Blood Test Coverage Criteria and Medical Necessity Requirements 2026

The real issue with NCD 167 is the diagnostic vs. screening split. These are not interchangeable billing categories. The indication on the claim drives which code you report, which frequency rules apply, and whether the claim has medical necessity support.

Under this coverage policy, CMS covers FOBT for diagnostic purposes when a patient has a known or suspected alimentary tract condition that could cause intestinal bleeding. It also covers the test to evaluate unexpected anemia, abnormal signs or symptoms linked to blood loss, and patient complaints of black or red-tinged stools. Those four indications are the medical necessity pillars for diagnostic FOBT billing.

When testing is performed for colorectal cancer screening — with no signs, symptoms, or complaints associated with GI blood loss — the billing rules change entirely. CMS requires a different HCPCS code for screening FOBT. The policy makes this explicit: the guaiac-based test used for screening should be deferred if other colon studies are performed first. If your team is reporting screening and diagnostic codes interchangeably, you have a claim denial problem waiting to happen.

The Three Test Types and Why They Matter for Medical Necessity

CMS recognizes three types of fecal hemoglobin assays. Each has different clinical utility, and that utility affects how you support medical necessity in documentation.

The guaiac-based test is the most widely used and the most sensitive for lower bowel bleeding. It requires intact heme peroxidase activity. Fecal hydration increases reactivity — and false positivity. Recent meat ingestion can also trigger a false positive. For screening use, these limitations matter. For diagnostic use with active indications, CMS says the test should be done despite its limitations.

The immunoassay targets the globin portion of hemoglobin. Diet and proximal gut bleeding affect it least, but fecal flora can destroy the antigen. The heme-porphyrin assay measures heme-derived porphyrin and is most useful for evaluating overall GI bleeding in iron deficiency anemia case finding — not colorectal cancer screening — because it can't distinguish dietary from endogenous heme.

If your physicians are ordering the heme-porphyrin assay for colorectal cancer screening, that's a documentation and medical necessity mismatch. Get your ordering providers aligned on which test type supports which clinical scenario.

Frequency Limitations Under NCD 167

The policy sets a specific frequency rule for one narrow patient population. For patients taking NSAIDs who have a history of GI bleeding but no other signs, symptoms, or complaints of GI blood loss, FOBT is generally appropriate no more than once every three months.

Outside that scenario, the policy doesn't set an explicit frequency cap for diagnostic use. But "generally appropriate" is CMS hedging. Don't treat that phrase as a green light for unlimited testing. Document the clinical rationale every time.

Prior authorization is not explicitly required under this NCD, but that doesn't mean your MAC has no additional requirements. Check your local coverage determination guidance and your Medicare Administrative Contractor's policies before assuming NCD 167 is the only document that governs your claims.

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CMS FOBT Exclusions and Non-Covered Indications

The policy doesn't use the word "experimental" for any FOBT test type. But there are functional coverage limits worth treating like exclusions.

Screening FOBT billed under a diagnostic indication is not covered. If a patient has no signs, symptoms, or complaints associated with GI blood loss and the test is purely for colorectal cancer screening, the diagnostic indication codes don't apply. Billing the wrong indication is a path to claim denial and, in audits, a compliance problem.

The policy also limits FOBT reporting to once per testing episode — meaning once for up to three separate specimens, whether that involves one or two tests per specimen. Splitting that episode across multiple claims is not appropriate under NCD 167.

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Coverage Indications at a Glance

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CMS Fecal Occult Blood Test Billing Guidelines and Action Items 2026

These are direct steps for your billing and revenue cycle team. Act on these before the effective date of March 7, 2026.

Copy Action Items

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CPT, HCPCS, and ICD-10 Codes for Fecal Occult Blood Test Under NCD 167

Covered Codes (When Medical Necessity Criteria Are Met)

The policy does not list specific CPT or HCPCS codes in the current version data. CMS references distinct HCPCS codes for diagnostic FOBT and screening FOBT, but the specific code values are not included in the NCD 167 policy document as published here.

Pull the current CMS HCPCS code set directly to confirm the correct codes for:

• Diagnostic fecal occult blood testing (guaiac-based, immunoassay, and heme-porphyrin variants)
• Screening fecal occult blood testing for colorectal cancer in asymptomatic patients

Do not use codes from memory or prior-year charge masters without verifying against the current CMS HCPCS release.

A Note on ICD-10 Diagnosis Code Alignment

While this policy does not enumerate ICD-10-CM codes, your diagnosis codes must map directly to one of the four covered indications for diagnostic billing:

• Known or suspected alimentary tract condition (e.g., Crohn's disease, ulcerative colitis, angiodysplasia, adenocarcinoma, acid-peptic disease)
• Unexpected anemia — including iron deficiency anemia with suspected GI blood loss
• Abnormal signs or symptoms associated with blood loss
• Patient complaint of melena or hematochezia

For screening claims, use the appropriate colorectal cancer screening ICD-10-CM code — not a symptom or disease code. Mixing a screening ICD-10 with a diagnostic HCPCS code, or vice versa, is a claim denial waiting to happen.

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