DraftUnitedHealthcarePolicy CS373OH.E

FDA Cleared or Approved Companion Diagnostic Testing (for Ohio Only)

Policy governing coverage and medical necessity of FDA-cleared or approved companion diagnostic tests for oncology in the state of Ohio; affects providers ordering CDx and related genomic testing for Ohio members.

Policy Summary

PayerUnitedHealthcare

PolicyFDA Cleared or Approved Companion Diagnostic Testing (for Ohio Only)

Policy CodePolicy CS373OH.E

Change TypeCodes added / operational

Effective DateJun 1, 2025

Next Review DateN/A

Key ActionWhen ordering CDx or broad genomic tests, document tumor type, stage, specimen type and FDA CDx status and obtain prior authorization when required (e.g., for newly added code 0543U).

SourceLink

POLICY UPDATE CHANGES

Applicable CPT code 0543U was added to the policy.

Previous policy version CS373OH.D was archived.

Ohiostate applicability

up to 3repeat CDx per year

30 daysconcurrent tissue/liquid window

0022U–0543UCPT/PLA codes referenced

>95%

Trek Health ingests and normalizes Transparency in Coverage data and payer policy updates to give provider organizations a clear view of how commercial reimbursement behaves across markets, payers, and services. Our platform transforms raw payer disclosures into structured intelligence that supports contract evaluation, payer negotiations, and service line strategy. By combining market benchmarks with ongoing policy visibility, Trek helps teams identify variability, risk, and opportunity in commercial reimbursement. The result is faster insight, stronger negotiating positions, and more informed financial decisions.

Coverage Criteria for Companion Diagnostic and Genomic Testing

Companion Diagnostic Coverage Criteria

Covered when ALL of the following are met:

General CDx coverage: CDx testing that is FDA-cleared or FDA-approved and intended to identify individuals for the safe and effective use of a corresponding therapeutic product, as described in test and therapeutic labeling and per the FDA List of Cleared or Approved Companion Diagnostic Devices.

Use FDA list; if no match, refer to Ohio Molecular Oncology policies (see InterQual CP when applicable)

Repeat testing: Repeat companion diagnostic testing on a new tissue or liquid biopsy specimen is considered medically necessary up to three times annually when CDx criteria are met and one of the following applies: cancer has progressed or did not respond to the most recent systemic therapy; the individual is experiencing disease recurrence.<=3 per year

Concurrent testing: Concurrent tissue-based and liquid biopsy CDx testing (ordered within 30 days of each other) is medically necessary for advanced/metastatic (stage IV) non-small cell lung cancer and advanced/metastatic (stage IV) breast cancer when CDx criteria are met.within 30 days

Coverage criteria — tissue CDx and evidence-supported CGP

Covered when ALL of the following are met

CDx-supported indication: Test is an FDA-approved or -cleared companion diagnostic used to identify a biomarker associated with an FDA-approved therapy for the patient's specific cancer type.

FoundationOne CDx cited as an analytically validated example

Evidence-supported CGP: For broad CGP use, published evidence demonstrates clinical validity and supports use to guide FDA-labeled targeted therapies, or analytic validation demonstrates high concordance for variant types required for clinical decision-making.

Hayes assessments and clinical studies should support clinical utility for the intended use

Not medically necessary / investigational

Not routinely covered / considered investigational when ANY of the following are met

Insufficient evidence tests: Test lacks peer‑reviewed evidence of clinical validity or utility for the intended broad molecular profiling indication (examples cited: Guardant360 TissueNext, MI Profile).

Hayes evaluations found insufficient published evidence for broad profiling indications

Heme/sarcoma CGP insufficient: Use of FoundationOne Heme for hematologic malignancies and sarcomas is considered investigational when published evidence of clinical utility is insufficient.

Hayes assessment identified insufficient evidence for this intended use

Liquid biopsy coverage guidance

Coverage guidance for liquid biopsy

Liquid biopsy appropriate uses: Liquid biopsy (ctDNA/cfDNA) may be considered when tissue biopsy is not possible or as a complementary approach to tissue testing in advanced/metastatic disease; reflex tissue biopsy is recommended when ctDNA tumor fraction is low or when liquid biopsy is negative but clinical suspicion for an actionable alteration remains.ctDNA tumor fraction < 1% (suggested trigger for reflex)

Studies show complementary detection and consensus guidance support reflex tissue confirmation when ctDNA is negative or TF is low

Monitoring/MRD and screening: Use of ctDNA for minimal residual disease (MRD) surveillance, routine monitoring, or population screening lacks sufficient evidence to be routinely covered outside research or defined guideline-supported indications.

Systematic reviews and professional society statements report insufficient evidence for routine MRD/screening use

Coverage for liquid biopsy as companion diagnostic

Covered when ALL of the following are met

Primary criteria: 1) Individual has an advanced or metastatic solid tumor for which identification of a genomic alteration would inform use of an FDA‑approved targeted therapy; AND 2) Testing is performed using an FDA‑cleared/approved ctDNA companion diagnostic (e.g., FoundationOne Liquid CDx, Guardant360 CDx) or an analytically validated ctDNA assay used per product labeling for tumor mutation profiling; AND 3) Tissue genotyping is unavailable or insufficient, or liquid biopsy is being used to expedite treatment initiation.

Hayes assessments and randomized and observational studies support utility of liquid CDx in these situations; negative ctDNA results may require tissue confirmation

Covered indications for tumor NGS and ctDNA

Covered when ALL of the following are met

Advanced or specific cancer types: Individual has advanced, unresectable, or metastatic cancer for which guideline‑based biomarker testing is recommended (examples include non‑squamous NSCLC, breast cancer, biliary tract cancers, ampullary adenocarcinoma, bladder cancer, CNS tumors, colorectal cancer, pancreatic adenocarcinoma, prostate cancer).

NCCN and other society guidelines cited support testing in these tumor types

Appropriate test modality: Testing is performed using an appropriately validated or FDA‑approved assay in a CLIA‑regulated laboratory; tumor tissue NGS is preferred, but validated plasma ctDNA assays are acceptable when tissue is unavailable or rapid results are required.

ASCO, ESMO, and NCCN guidance emphasize use of validated assays and CLIA‑regulated labs

Clinical intent: Results will be used to select or exclude a biomarker‑linked therapy or determine eligibility for targeted therapy or clinical trials (examples: PIK3CA, AKT1, PTEN, ESR1, MSI/MMR, NTRK, MET exon 14, RAS/BRAF, HER2, FGFR, IDH alterations).

Guidelines and trials cited link detection of these alterations to therapy selection

Not medically necessary or investigational contexts

Not covered / Limited utility when

Limited evidence contexts: Use of ctDNA assays for early‑stage cancer screening, routine surveillance for residual disease, or general population screening is considered not medically necessary due to insufficient evidence of clinical validity and utility.

ASCO and systematic reviews report limited evidence supporting these uses

Coverage aligned with NCCN tumor-specific CGP/ctDNA recommendations

Covered when aligned with NCCN guidance for specific tumor types and clinical situations

General principles: Tissue‑based molecular profiling is preferred; validated plasma ctDNA/CGP may be considered when tissue biopsy is not feasible or tissue is unavailable. Broad NGS or panel‑based testing is preferred for advanced/metastatic disease when multiple biomarkers may inform treatment.

Supported across multiple NCCN tumor‑specific guidelines

Tumor‑specific considerations: Use of CGP/ctDNA is acceptable in tumor‑specific scenarios per NCCN (examples include: persistent/recurrent cervical cancer; metastatic colorectal cancer with RAS/BRAF/HER2/MSI testing; gastric/esophageal cancers when tissue limited; GIST for driver mutation testing; histiocytic neoplasms for MAPK pathway and fusions; selected use in HCC; melanoma stage IV/recurrence; neuroblastoma MYCN/ALK/SCAs; neuroendocrine/adrenal unresectable/metastatic disease; NSCLC broad panel NGS and ctDNA adjunct in metastatic disease; occult primary cancers for NGS; pancreatic adenocarcinoma for somatic profiling including RNA fusion detection; prostate cancer tumor molecular evaluation with ctDNA if biopsy infeasible; small cell lung cancer in select cases; thyroid carcinoma for BRAFi/other molecular testing; uterine neoplasms for comprehensive molecular testing including NTRK/MSI/TMB; vaginal cancer for NGS/CGP in recurrent/persistent disease).

Each tumor entry aligns with cited NCCN guideline sections

Vaginal Cancer - Testing Recommendation

Covered when ALL of the following are met for vaginal cancer consideration:

Vaginal cancer CGP/NGS guidance: NGS and comprehensive molecular profiling (CMP) is recommended for consideration in individuals with recurrent or persistent vaginal cancer to assist selection of systemic therapy; tissue biopsy is preferred, and if tissue is unavailable or biopsy is not feasible, CGP via a validated ctDNA assay may be considered.

Source: NCCN Vaginal Cancer Guidelines v2.2025

If a test is not listed on the FDA "List of Cleared or Approved Companion Diagnostic Devices," coverage determinations should follow the referenced Ohio Molecular Oncology Testing policies. The policy directs reviewers to the Medical Policy titled "Molecular Oncology Testing for Solid Tumor Cancer Diagnosis, Prognosis, and Treatment Decisions (for Ohio Only)" or the analogous hematologic cancer policy and to InterQual CP criteria for Comprehensive Genomic Profiling (tumor tissue and liquid biopsy) for assessment of medical necessity and appropriateness.

Broad molecular profiling tests and tumor CGP platforms that lack peer‑reviewed evidence of clinical validity or utility for a broad profiling indication are considered investigational and are not routinely covered. Examples specifically cited include Guardant360 TissueNext and the MI Profile, for which Hayes assessments identified insufficient published data to support clinical utility as general broad-profiling tools.

Comprehensive cfDNA panels that include hundreds of genes—such as FoundationOne Liquid CDx, which assays >300 genes—may include many genes beyond those tied to current FDA CDx indications. The policy notes that only a small subset of genes on such large panels are incorporated in FDA CDx indications and that evidence is not conclusive that the broader gene content translates into improved clinical outcomes versus more limited, guideline‑directed testing.

Use of circulating tumor DNA (ctDNA) assays for early‑stage cancer screening, routine treatment monitoring, or detection of minimal residual disease (MRD) is not supported by sufficient evidence of clinical validity and utility. The ASCO/CAP review and related assessments found little or no evidence that ctDNA testing in early‑stage disease, surveillance, or screening reliably improves clinical outcomes, and therefore these uses are not routinely covered.

ctDNA testing should not be used in lieu of a histologic tissue diagnosis. The guidance emphasizes that tissue‑based testing remains the preferred diagnostic standard and that ctDNA is generally reserved for advanced/metastatic situations, when tissue is unavailable, or as a complementary approach; use of ctDNA as a substitute for obtaining histology may risk denial because it does not replace the requirement for a histologic diagnosis.

FDA approval or clearance of a test is provided for informational context only; FDA labeling or approval alone is not, by itself, a basis for coverage. The policy instructs reviewers to use the FDA list of cleared/approved companion diagnostics and to apply the plan's clinical coverage criteria and applicable state or contractual requirements when making coverage determinations.

Listing a procedure or PLA/CPT code in this policy is for administrative reference and does not imply that the service represented by that code is covered. Benefit coverage and payment remain subject to federal, state, and contractual requirements, and inclusion of a code does not guarantee reimbursement.

Use of broad genomic profiling solely as routine population screening or as an automatic method to guide therapy selection—absent evidence demonstrating improved clinical outcomes—is discouraged and may be considered not medically necessary. Hayes and trial evidence cited in the policy indicate limited impact on outcomes when broad profiling is used indiscriminately outside guideline‑directed indications.

Use of broad comprehensive ctDNA panels solely for screening or in clinical settings without advanced/metastatic disease or without an intent to guide FDA‑approved targeted therapy is not supported by the available evidence. Assessments and prospective studies cited in the policy found insufficient high‑quality evidence to justify routine use of expansive ctDNA panels for early detection or general screening purposes.

Routine use of ctDNA assays in early‑stage disease, for general surveillance, or for other purposes without demonstrated clinical utility is considered unproven and is not routinely covered. The policy references systematic reviews and guideline statements that found limited evidence supporting ctDNA use outside specific advanced‑stage, guideline‑recommended indications.

Routine ctDNA testing in early‑stage disease (stage I–III) and routine repeat testing after standard cytotoxic chemotherapy—where molecular changes are infrequent—is generally low value and not recommended. The document notes that repeat profiling is more appropriately considered after targeted therapy progression or when limited initial testing or sample quality justifies re‑evaluation.

Covered Clinical Indications

CDx testing to identify patients most likely to benefit from a specific therapeutic product or at increased risk for side effects

CDx intended use and labeling: Companion diagnostic (CDx) testing is intended to identify patients most likely to benefit from a specific therapeutic product, identify those at increased risk for adverse effects, or to require monitoring for response to a product; the intended use must be described in the test and therapeutic labeling and CDx status is determined using the FDA List of Cleared or Approved Companion Diagnostic Devices.

Use FDA list to identify CDx tests

Detection of biomarkers associated with FDA-approved therapies for the patient's tumor type (example: FoundationOne CDx validation)

Detection of FDA‑linked biomarkers: Detection of biomarkers associated with FDA‑approved therapies for the patient's specific tumor type using an FDA‑cleared companion diagnostic (example: FoundationOne CDx with analytic validation and reported clinical utility data).

F1CDx analytically validated across variant types; cohort success rates >95% reported

Provider Actions, Documentation, and Prior Authorization

Billing Rule

Code Listing and Coverage

Listing of a code in this policy does not imply that the service described by the code is a covered or non-covered health service. Benefit coverage for health services is determined by federal, state (including the Ohio Administrative Code), or contractual requirements and applicable laws. Inclusion of a code does not imply any right to reimbursement or guarantee claim payment. Other policies and guidelines may apply.

CPT code 0543U was added 06/01/2025 — presence in this policy does not guarantee coverage

Prior Authorization

Low ctDNA Tumor Fraction — Risk and Action

Low ctDNA tumor fraction reduces sensitivity of plasma-based (ctDNA) assays and increases the risk of false-negative results. When ctDNA tumor fraction is low, consider reflex tissue testing or obtaining an alternative specimen to avoid missed actionable alterations.

Coding and Test Listings

Not Covered or Investigational Uses

Specific commercial tests (for example, CANCERPLEX) lack sufficient peer‑reviewed evidence of clinical validity for certain intended uses and therefore are identified as not covered for those indications. The Hayes assessment cited concluded that evidence addressing clinical validity and utility for some claimed uses of CANCERPLEX is insufficient at this time.

Tests that lack sufficient peer‑reviewed evidence of clinical validity or utility for broad molecular profiling indications (for example, Guardant360 TissueNext and the MI Profile) are considered investigational and are not covered for those broad profiling purposes according to Hayes assessments cited in the policy.

FoundationOne Heme is not covered for hematologic malignancies and sarcomas because published evidence is insufficient to establish clinical validity and utility for these tumor types. Hayes concluded that additional high‑quality studies are required before routine coverage can be supported.

Use of broad ctDNA panels for early cancer detection or population screening is not supported by the evidence cited. The Hayes assessments and related evaluations found the quality of available studies to be very poor for broad screening uses, and therefore these indications are not covered.

ctDNA testing for screening, routine monitoring in early‑stage cancer, or residual disease detection lacks sufficient evidence of clinical utility and is therefore considered not covered for these purposes in routine clinical practice.

Routine ctDNA testing outside of advanced or metastatic disease and use of ctDNA in place of histologic diagnosis are not supported and are considered not covered. The policy emphasizes that tissue testing is preferred in non‑advanced settings and that ctDNA should not replace histologic confirmation.

Definitions and Terms

Advanced Cancer — definition

DefinitionAdvanced Cancer: Cancer that is unlikely to be cured or controlled with treatment (also called end-stage or terminal cancer).

Clinical implicationOften denotes patients with metastatic or unresectable disease where biomarker testing may guide systemic therapy

SourceNational Cancer Institute (NCI) definition referenced in policy

Companion Diagnostic Test — definition

DefinitionCompanion Diagnostic Test: A test that provides important information for the safe and effective use of a corresponding therapeutic drug (FDA-defined).

Regulatory noteUse the FDA List of Cleared or Approved Companion Diagnostic Devices to identify CDx tests; FDA approval alone is informational and not by itself a basis for coverage

Background and Rationale

Companion diagnostic (CDx) testing identifies biomarkers required for the safe and effective use of specific therapeutic drugs and can guide selection of targeted therapies, avoidance of adverse effects, and monitoring where indicated. CDx intended use is defined in the test and therapeutic labeling; the policy uses the FDA "List of Cleared or Approved Companion Diagnostic Devices" as the reference standard for identifying CDx assays. Comprehensive genomic profiling (CGP) and liquid biopsy are NGS‑based approaches used to detect genomic alterations across many genes, but CDx designation and intended use determine applicability for matching patients to specific FDA‑approved therapies.

Policy Summary

PayerUnitedHealthcare

PolicyFDA Cleared or Approved Companion Diagnostic Testing (for Ohio Only)

Policy CodePolicy CS373OH.E

Change TypeCodes added / operational

Effective DateJun 1, 2025

Next Review DateN/A

Key ActionWhen ordering CDx or broad genomic tests, document tumor type, stage, specimen type and FDA CDx status and obtain prior authorization when required (e.g., for newly added code 0543U).

SourceLink

On This Page

Repeat testing: Repeat molecular testing is generally not recommended after standard cytotoxic chemotherapy but may be considered after progression on targeted therapy or when initial testing used lower‑sensitivity methods or sample quality was inadequate.

NCCN guidance favors repeat testing primarily when clinically indicated by progression or prior limited testing

Test performance and interpretation: ctDNA and tissue testing have high specificity but notable false‑negative rates; negative ctDNA results should be interpreted cautiously and not used in lieu of histologic diagnosis; be aware of clonal hematopoiesis (CHIP) interference in some contexts (e.g., prostate cancer).

NCCN cautions and professional society reviews emphasize complementary use

Use of liquid biopsy to identify actionable alterations in advanced/metastatic disease when tissue is not feasible or to complement tissue testing

Liquid biopsy when tissue not feasible: Liquid biopsy (ctDNA) may be used to identify actionable alterations in advanced/metastatic disease when tissue biopsy is not feasible or to complement tissue testing; negative liquid results should prompt tissue confirmation when clinically indicated.

Consensus guidance and comparative studies support liquid as alternative or complement; reflex tissue recommended for negative results

Advanced or metastatic solid tumors where identification of actionable genomic alterations will inform targeted FDA-approved therapy

Advanced/metastatic solid tumors informing targeted therapy: Use tumor NGS or validated plasma ctDNA assays in advanced or metastatic solid tumors where identification of actionable genomic alterations will inform use of FDA‑approved targeted therapy (examples include NSCLC, breast, colorectal, prostate, ovarian cancers).

Guidelines and studies cited demonstrate utility for these tumor types; liquid CDx useful when tissue is unavailable or to expedite therapy

Detection of actionable somatic mutations in advanced/metastatic cancers to guide targeted therapy

Detection of actionable somatic mutations to guide targeted therapy: Testing to detect actionable somatic mutations (examples: PIK3CA in HR+ breast cancer for alpelisib; AKT1/PI3K/PTEN for AKT inhibitor trials; RAS/BRAF/HER2/MMR for colorectal cancer) is indicated when results will inform target‑directed therapy; use tumor NGS or validated plasma cfDNA when tissue is unavailable and reflex tissue testing if ctDNA is negative and clinical suspicion persists.

ASCO and NCCN guidance support testing of these biomarkers

Metastatic colorectal cancer and NSCLC — broad molecular profiling

Metastatic CRC and NSCLC broad profiling: For metastatic colorectal cancer and metastatic NSCLC, broad molecular profiling (including RAS, BRAF, HER2, MSI/MMR, and other guideline‑listed biomarkers) is recommended; tissue testing is preferred but validated ctDNA is acceptable when tissue is unavailable.

NCCN prefers NGS/broad panel testing in these settings

Recurrent or persistent vaginal cancer to assist selection of systemic therapy

Vaginal cancer recurrent/persistent testing: For recurrent or persistent vaginal cancer, tissue‑based NGS/CMP is preferred to assist selection of systemic therapy; if tissue is unavailable or biopsy not feasible, ctDNA CGP is acceptable as an alternative per NCCN v2.2025.

NCCN Vaginal Cancer Guidelines v2.2025 cited

Document measured/estimated ctDNA tumor fraction when available
If ctDNA tumor fraction < 1–10% (per assay-specific guidance), plan for reflex tissue testing

Denial Risk

Limited Evidence Contexts — Denial Risk

There is limited evidence supporting clinical validity and utility for many ctDNA assays in contexts other than advanced or metastatic disease (for example early-stage cancer, routine monitoring, minimal residual disease detection, or screening). Use of ctDNA testing in these contexts is discouraged and may lead to denial if used in lieu of a histologic tissue diagnosis.

Do not substitute ctDNA for histologic tissue diagnosis
Reserve ctDNA testing primarily for advanced/metastatic disease or when tissue is unavailable

Documentation Required

State / Contractual Requirements — Verify Before Ordering

Coverage decisions must reference and comply with governing federal, state (Ohio Administrative Code), or contractual requirements. In the event of a conflict between this policy and applicable federal, state, or contractual requirements, the federal, state (OAC), or contractual requirements govern and may affect coverage determinations.

Verify member benefits and any state- or contract-specific mandates before ordering
Ohio-specific molecular oncology policies may apply

Note

Use FDA List to Identify CDx Tests

Use the FDA List of Cleared or Approved Companion Diagnostic Devices to identify FDA-cleared/approved CDx tests. If no match is found on the FDA list for the intended biomarker/test combination, refer to the Molecular Oncology Testing medical policies (solid tumor or hematologic) for Ohio-specific review and coverage guidance.

If ordering a CDx, document the exact test name and confirm it appears on the FDA CDx list when applicable
If not on FDA list, follow the Molecular Oncology Testing policies for review

Documentation Required

Required Clinical Documentation for CDx Use

When ordering an FDA-cleared or FDA-approved Companion Diagnostic (CDx), document the tumor type, clinical indication/intent, prior therapies (including lines of therapy and response), and the specific therapeutic product or class the test will inform. This supporting documentation is required to substantiate medical necessity for CDx-directed testing.

Document tumor histology and stage (e.g., advanced/metastatic)
List prior systemic or endocrine therapies and dates
State the therapeutic agent or class linked to the CDx result

Documentation Required

General Required Clinical Documentation

For molecular/genomic testing generally, document the clinical indication (advanced/metastatic disease when applicable), specimen type (tissue vs plasma), test platform, and rationale for testing (e.g., guide targeted therapy selection, assess resistance after progression). Include whether tissue is unavailable or insufficient when ordering ctDNA testing.

Specify specimen source (archival tissue, fresh tissue, plasma) and why chosen
If ordering ctDNA, document if tissue biopsy is infeasible or unavailable

Prior Authorization

Actions When Tissue Testing Fails

When tissue-based testing fails for technical reasons (eg, insufficient quantity or assay failure), pursue alternate testing modalities or obtain additional tissue when feasible. ctDNA may be complementary and useful when tissue procurement is not possible, but negative ctDNA results should prompt reflex tissue testing when clinically indicated.

Document the reason tissue testing failed and attempts made to obtain adequate tissue
If reflexing to ctDNA, record plan for confirmatory tissue testing if ctDNA is negative

Documentation Required

Laboratory and FDA Information

Laboratories performing molecular/genomic testing must be CLIA-certified. When an FDA-cleared/approved CDx is applicable, provide documentation identifying the FDA-cleared/approved test and the laboratory performing the assay. FDA approval alone is informational; coverage decisions also consider medical necessity and governing coverage rules.

Include CLIA certification status of the performing laboratory on the request or supporting documentation
Provide the FDA CDx labeling or reference when relying on an FDA-cleared/approved CDx

Documentation Required

Therapy Sequencing — Documentation

Therapy sequencing documentation: When testing is intended to determine eligibility for specific targeted agents or to guide sequencing of endocrine/systemic therapies, document prior lines of therapy, reason for change (progression, recurrence, resistance), and how the test result will influence next-line treatment selection.

Record prior targeted or endocrine therapies and duration/response
State whether testing is for identification of acquired resistance mechanisms or for initial biomarker identification to guide targeted therapy

Note

Other Provider Actions — Verify and Document

Provider actions not otherwise specified in this excerpt: always verify member-specific coverage, obtain prior authorization if required by the plan or state-specific rules, and retain complete clinical records supporting the medical necessity of testing.

Check plan benefit design and prior authorization requirements before testing
Retain pathology reports, prior treatment records, and test requisitions for audit

Intended useIntended use must be described in test and therapeutic labeling to support CDx designation

Comprehensive Genomic Profiling (CGP) — definition

DefinitionComprehensive Genomic Profiling (CGP): An NGS test that detects multiple classes of genomic alterations across hundreds of genes from a single sample.

Panel content exampleExample: FoundationOne CDx analyzes 324 genes and reports short variants, copy number alterations, rearrangements, TMB and MSI

PurposeUsed to identify actionable somatic alterations to guide targeted therapy selection or trial eligibility

Liquid Biopsy — definition

DefinitionLiquid Biopsy: Minimally invasive testing of bodily fluids (most commonly plasma) to identify circulating tumor cells or circulating tumor-derived nucleic acids (ctDNA/cfDNA) and other analytes to detect tumor genomic alterations.

Use casesMay be used when tissue is unavailable, to expedite treatment, or to detect acquired alterations; examples include FoundationOne Liquid CDx and Guardant360 CDx

LimitationsAssay sensitivity depends on ctDNA tumor fraction; some alterations (e.g., certain CNAs, fusions) may be less reliably detected depending on assay

Next Generation Sequencing (NGS) — definition

DefinitionNext Generation Sequencing (NGS): High-throughput sequencing techniques that can quickly analyze multiple DNA sections simultaneously and are commonly used for multigene tumor panels.

Role in CGPNGS is the primary method for comprehensive genomic profiling to detect mutations, copy number changes, rearrangements, and biomarkers like TMB/MSI

Testing considerationsNGS panel size and content should match clinical intent; larger panels (>50 genes) may be appropriate per NCCN for some tumor types

Comprehensive Genomic Profiling (CGP) — NGS-based analysis

DefinitionComprehensive Genomic Profiling (CGP): NGS-based analysis of large gene panels to detect short variants, copy number alterations, rearrangements, and biomarkers such as TMB and MSI from tumor tissue or circulating tumor DNA.

Assay examplesFDA-approved tissue CGP example: FoundationOne CDx (324 genes); liquid CGP example: FoundationOne Liquid CDx (>300 genes)

Intended useCan be used to identify biomarkers linked to FDA-approved therapies or to support enrollment in targeted clinical trials when validated

Liquid biopsy — minimally invasive analysis

DefinitionLiquid biopsy (minimally invasive): Analysis of circulating tumor-derived analytes (ctDNA/cfDNA, CTCs, RNA, proteins) from bodily fluids to detect tumor genomic alterations.

BenefitsOften offers faster turnaround and can be used when tissue biopsy is infeasible; may detect emergent resistance mutations

Concordance noteStudies show high concordance for many variants (e.g., 97% CTC vs ctDNA concordance in CRC study) but limitations exist depending on mutation type and tumor fraction

Liquid biopsy — noninvasive plasma testing of ctDNA/CTCs

DefinitionLiquid biopsy (plasma ctDNA/CTC): Noninvasive testing of circulating cell-free tumor DNA (ctDNA) or circulating tumor cells (CTCs) from plasma to detect genomic alterations for tumor profiling and treatment selection.

RecommendationctDNA testing can complement tissue testing in metastatic disease; tissue is preferred in early-stage disease per guideline statements

Reflex testingReflex tissue biopsy is recommended when ctDNA tumor fraction is low or when ctDNA result is negative but clinical suspicion remains

Variant Allele Fraction (VAF) — definition and example LoD

DefinitionVariant Allele Fraction (VAF): The proportion of DNA fragments in a sample that carry a specific variant; analytic limits of detection are reported for assays (example: 0.40% VAF for select alterations in FoundationOne Liquid CDx).

Analytic exampleFoundationOne Liquid CDx reported 95% LoD of 0.40% VAF for select substitutions/indels and 0.37% for select rearrangements

Clinical implicationLower VAFs require high-sensitivity assays; low VAF or low ctDNA tumor fraction may reduce sensitivity and trigger reflex tissue testing

ctDNA / liquid biopsy — plasma testing when tissue unavailable

DefinitionctDNA / liquid biopsy: Circulating tumor DNA testing performed on plasma that can detect somatic genomic alterations and may be used when tissue is unavailable or to expedite treatment decisions.

Assay limitationsDetection of some alteration types (e.g., copy-number changes, certain fusions) may be less reliable depending on the assay and tumor fraction

Use caseGuidelines support ctDNA use in advanced/metastatic disease; negative ctDNA results should prompt consideration of tissue genotyping when clinically indicated

Tumor NGS / Comprehensive Genomic Profiling (CGP) — definition

DefinitionTumor NGS / Comprehensive Genomic Profiling (CGP): Next-generation sequencing performed on tumor tissue (or validated plasma assays) to identify a broad range of genomic alterations, including mutations, fusions, copy number changes, and biomarkers like TMB/MSI.

Preferred specimenTissue-based NGS is preferred when feasible; validated plasma assays acceptable when tissue is unavailable or when rapid results are needed

Example assayFoundationOne CDx is an FDA-approved tumor CGP assay with analytic validation across 324 genes

Broad molecular profiling — definition

DefinitionBroad molecular profiling: Molecular testing that can identify all biomarkers listed in the relevant NCCN guideline via either a single assay or combination of limited assays; NGS is the most common approach.

Panel sizingPanels larger than 50 genes may be appropriate for following NCCN testing recommendations for some tumor types

PurposeIntended to detect a wide array of actionable and emerging biomarkers to inform targeted therapy selection or clinical trial enrollment

ctDNA — specificity and false-negative considerations

DefinitionctDNA: Circulating tumor DNA in plasma used for tumor genomic profiling; tests have high specificity but notable false-negative rates, so complementary tissue testing is recommended when results are negative and clinical suspicion remains.

Specificity vs sensitivityBoth ctDNA and tissue testing have very high specificity but considerable false-negative rates; complementary use can reduce false negatives

Clinical cautionBe aware of potential confounders such as clonal hematopoiesis (CHIP) which can affect interpretation of some ctDNA findings

Companion Diagnostic — FDA-cleared/approved test definition

DefinitionCompanion Diagnostic: An FDA-cleared or -approved test used to identify patients likely to benefit from a specific therapeutic product; the FDA maintains a List of Cleared or Approved Companion Diagnostic Devices.

Coverage noteThe FDA list is used to identify CDx tests; FDA approval alone is informational and not solely a basis for coverage determinations

Laboratory regulationWhen relying on CDx labeling, testing laboratories should be CLIA-regulated as referenced in policy guidance

CLIA-regulated laboratory — definition

DefinitionCLIA-regulated laboratory: Laboratories that perform genetic tests are regulated under the Clinical Laboratory Improvement Amendments (CLIA) Act of 1988.

Policy requirementTesting should be performed in appropriately certified/CLIA-regulated laboratories when relying on assay results for coverage decisions

ReferenceMore information available from FDA and CLIA resources cited in policy

CGP via ctDNA assay — definition and use

DefinitionCGP via ctDNA assay: Comprehensive genomic profiling using circulating tumor DNA (liquid biopsy) considered when tissue biopsy is not available or feasible.

When to useConsidered when tissue is unavailable, biopsy is not possible, or when rapid results are required to guide treatment; ctDNA CGP may complement or substitute tissue in these contexts per guidelines

LimitationsSome biomarkers and alteration classes (e.g., certain CNAs or fusions) may be less reliably detected by ctDNA assays depending on analytic performance and tumor fraction