CurrentEmblemHealthPolicy AHS-M2067

Therapeutic Drug Monitoring for 5‑Fluorouracil - Lab Benefit Program (LBM)

This reimbursement policy governs coverage and billing guidance for therapeutic drug monitoring (TDM) of 5‑fluorouracil for individuals receiving 5‑FU chemotherapy under the Lab Benefit Program (LBM), including which tests meet or do not meet coverage criteria.

Policy Summary

PayerEmblemHealth

PolicyTherapeutic Drug Monitoring for 5‑Fluorouracil - Lab Benefit Program (LBM)

Policy CodePolicy AHS-M2067

Change TypeAdministrative clarification / template update

Effective DateJun 13, 2025

Next Review Date

Key ActionTherapeutic drug monitoring (TDM) to aid in managing dose adjustment for individuals receiving 5‑fluorouracil chemotherapy meets coverage criteria; uracil breath tests and dihydrouracil/uracil ratio testing do not meet coverage.

SourceLink

POLICY UPDATE CHANGES

Updated for clarity; no changes to coding or coverage criteria.

Reformatted and reorganized policy, transferred content to new template with new Reimbursement Policy Number.

20–30recommended 5‑FU therapeutic AUC range cited

654meta-analysis sample

208Gamelin RCT sample

58%proportion achieving target AUC after TDM

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S3722,80299,82542,83789referenced procedure codes

nomaterial change status

Coverage criteria for 5‑FU Therapeutic Drug Monitoring

Coverage criteria and exclusions

Covered when ALL of the following are met:

For individuals who are undergoing 5-fluorouracil (5-FU) chemotherapy, therapeutic drug monitoring (TDM) to aid in managing dose adjustment meets coverage criteria.

Exclusions (these DO NOT meet coverage criteria)

Uracil breath tests.
Dihydrouracil/uracil ratio testing of plasma, serum, or urine samples.

Coverage considerations and evidentiary nodes

Guidance, recommendations, and evidentiary considerations relevant to clinical use of 5‑FU TDM and related DPD testing:

Professional society guidance

IATDMCT: AUC is the accepted and clinically relevant metric for assessing systemic 5‑FU exposure; TDM reduces variability and toxicity and is strongly recommended for management of 5‑FU in colorectal and head‑and‑neck cancer.
CPIC: Pharmacokinetically‑guided dosing increases the proportion of patients with AUC in the therapeutic range and reduces adverse effects; follow‑up TDM is recommended after genotype‑guided dose reductions.
CPIC/LBM guidance: For DPYD poor metabolizers, avoid 5‑FU; if no alternatives, give a strongly reduced dose combined with early TDM.
RNPGx/GPCO and French groups: Recommend DPD testing before FP chemotherapy and recommend 5‑FU TDM in partial DPD‑deficient patients.
EMA (PRAC): Recommend DPD deficiency testing (genotyping or plasma uracil) before initiation; contraindicate 5‑FU in complete DPD deficiency and adjust dose in partial deficiency.

Assay and coding considerations

Procedure codes referenced for AUC dose optimization and analytic methods include S3722, 80299, 82542, 83789 (informational for claim submission).
NICE: My5‑FU assay noted as having promise but recommended only for research purposes in their review (informing evidence context).

Evidence and economic context

Clinical trials and systematic reviews (e.g., Deng et al., Gamelin/PREDICT studies) report that AUC‑based dosing can increase proportion of patients achieving therapeutic AUC and reduce certain toxicities (diarrhea, mucositis).
Economic evaluations (e.g., Vithanachchi et al.) commonly find TDM for 5‑FU to be cost‑effective or cost‑saving in included studies.
Comparative assay evaluations (e.g., My5‑FU immunoassay vs LC‑MS/MS) and breath test reviews highlight variable analytic approaches; the uracil breath test is not recommended by IATDMCT for clinical dosing decisions.

Regulatory and implementation notes

Many 5‑FU assays are laboratory‑developed tests (LDTs) and are subject to CLIA; FDA prescribing information does not include AUC‑based dosing for fluorouracil.

Coverage summary and evidence (administrative clarification)

Administrative summary and evidence references:

This policy was updated for clarity with no changes to coding or coverage criteria as noted in the revision history.

References supporting the policy and evidence discussion are provided (selected examples include systematic reviews, guideline statements, clinical trials, assay evaluations, and economic evaluations).

Procedure codes cited in the policy for informational use include S3722, 80299, 82542, and 83789. Coding and coverage remain unchanged in this revision.

Procedure and billing codes

Applicable CPT/HCPCS procedure codesmixed

No codes listed

Referenced procedure codesCPT | HCPCS | mixed

S3722	Dose optimization by area under the curve (AUC) analysis, for infusional 5‑fluorouracil.
80299	Quantitation of therapeutic drug, not elsewhere specified.
82542	Column chromatography, includes mass spectrometry, if performed (e.g., HPLC, LC, LC/MS, LC/MS‑MS, GC, GC/MS‑MS, GC/MS, HPLC/MS), non‑drug analyte(s) not elsewhere specified, qualitative or quantitative, each specimen.
83789	Mass spectrometry and tandem mass spectrometry (e.g., MS, MS/MS, MALDI, MS‑TOF, QTOF), non‑drug analyte(s) not elsewhere specified, qualitative or quantitative, each specimen.

Coding changesmixed

No codes listed

inv-07: Therapeutic AUC target

Therapeutic AUC target20–30 mg×h/L

Unitsmg×h/L (milligrams × hours per liter)

Clinical contextTarget applies to intravenous continuous‑infusion 5‑fluorouracil dosing

inv-08: AUC target relevance

Primary relevanceAUC is the accepted and clinically relevant metric for systemic 5‑FU exposure and correlates with both clinical activity and toxicity

Use in dosingPharmacokinetically‑guided (AUC‑based) dosing increases proportion of patients achieving target exposure and reduces adverse effects

Provider guidance, billing impact, and reimbursement notes

Prior Authorization

Coverage decision summary / prior authorization implication

Therapeutic drug monitoring (TDM) for 5‑fluorouracil (5‑FU) is covered when used to guide dose adjustment for individuals receiving 5‑FU chemotherapy; prior authorization may be required per the member’s benefit plan. Uracil breath tests and dihydrouracil/uracil ratio testing of plasma, serum, or urine DO NOT meet coverage criteria and are not covered.

Covered for dose adjustment of infusional 5‑FU when clinically indicated — verify member benefits and obtain prior authorization if required.
Not covered: Uracil breath tests; dihydrouracil/uracil ratio testing of plasma, serum, or urine.

Billing Rule

Procedure codes for 5‑FU TDM (codes referenced for dose optimization and laboratory quantitation)

Key terms and acronyms

inv-12: Key acronyms and test terms (5-FU, AUC, BSA, DPD/DPYD, TDM)

5‑FU5‑fluorouracil (antineoplastic agent)

AUCArea‑under‑curve (plasma concentration vs time) — metric for systemic drug exposure

BSABody surface area — common dosing method for 5‑FU

DPD / DPYDDihydropyrimidine dehydrogenase (enzyme) / DPYD (gene) — variants can cause decreased 5‑FU metabolism

TDMTherapeutic drug monitoring — measuring drug concentrations to guide dosing

inv-13: Area under the curve (AUC) — accepted metric for 5‑FU exposure

Definition

Policy Summary

PayerEmblemHealth

PolicyTherapeutic Drug Monitoring for 5‑Fluorouracil - Lab Benefit Program (LBM)

Policy CodePolicy AHS-M2067

Change TypeAdministrative clarification / template update

Effective DateJun 13, 2025

Next Review Date

SourceLink

On This Page

Guideline supportIATDMCT and CPIC endorse AUC measurement/TDM to guide dose adjustment and follow‑up monitoring after genotype‑based dose changes

Codes referenced below may be used when billing for 5‑FU TDM and related laboratory quantitation; confirm code applicability with the payer and submit documentation supporting medical necessity.

S3722 — Dose optimization by AUC analysis for infusional 5‑fluorouracil.
80299 — Quantitation of therapeutic drug, not elsewhere specified.
82542 — Column chromatography, includes mass spectrometry (eg, HPLC, LC, LC/MS, LC/MS-MS, GC, GC/MS-MS, GC/MS, HPLC/MS).
83789 — Mass spectrometry and tandem mass spectrometry (eg, MS, MS/MS, MALDI, MS-TOF, QTOF).

Note

Reimbursement Policy - evidence references (context for reimbursement; no PA/step therapy specified)

Evidence and guidance supporting the reimbursement position for 5‑FU TDM include peer‑reviewed studies, assay comparisons, and health-technology guidance. Reviewers should reference these publications when documenting medical necessity for testing under the Lab Benefit Program (LBM).

Hashimoto Y et al. Current Status of Therapeutic Drug Monitoring of 5‑Fluorouracil Prodrugs. Anticancer Res. 2020;40(8):4655-4661.
MyCare. Clinical Studies and process information (My5‑FU assay). https://mycaretests.com/oncology/clinicians/#process
NICE. Fluorouracil chemotherapy: The My5‑FU assay for guiding dose adjustment. Updated Dec 10, 2014. https://www.nice.org.uk/guidance/dg16
Cunha‑Junior GF et al. (13)C‑uracil breath test to predict 5‑FU toxicity. Cancer Chemother Pharmacol. 2013;72(6):1273-1282.
Ezzeldin HH et al. (13)C‑5‑FU breath test review. J Breath Res. 2009;3(4):047002.
Buchel B et al. Comparative evaluation of the My5‑FU immunoassay and LC‑MS/MS. Clin Chem Lab Med. 2013;51(8):1681-1688.

Area under the curve (AUC) — plasma concentration vs time metric accepted as clinically relevant for systemic 5‑FU exposure

Relationship to outcomesObserved correlations between 5‑FU AUC and both clinical activity (response, survival) and toxicity across disease types and dosing regimens

Role in TDMUsed to guide pharmacokinetically‑guided dosing adjustments to increase the proportion of patients within the therapeutic window

inv-14: DPD deficiency — DPYD variants and uracil levels relevance

DPD deficiency — relevanceDPD deficiency (due to DPYD variants or abnormal plasma uracil) increases risk of severe 5‑FU toxicity; testing is recommended prior to therapy

Testing methodsGenotyping for DPYD variants and phenotyping by measurement of plasma uracil levels are cited as suitable approaches

Regulatory guidanceEMA/PRAC recommends DPD deficiency testing before initiating fluoropyrimidine therapy and contraindicates use in complete DPD deficiency

inv-15: Lab Benefit Program (LBM) — reimbursement pathway referenced

Program referencedLab Benefit Program (LBM) — reimbursement pathway for laboratory‑based TDM services related to 5‑FU

ContextPolicy frames coverage and billing guidance for 5‑FU TDM within the LBM

Supporting citationsLBM policy references multiple clinical and guideline sources (e.g., IATDMCT, CPIC, NICE) in its evidence base

inv-16: DPD screening / phenotyping (plasma uracil) referenced as related testing

DPD screening/phenotyping referencedPlasma uracil measurement is cited as a phenotyping method for DPD deficiency relevant to 5‑FU toxicity mitigation

Relation to coverageDPD screening (genotyping or plasma uracil) is recommended by EMA/PRAC and discussed as related testing in the policy

Distinction from excluded testsThe policy specifies that uracil breath tests and dihydrouracil/uracil ratio testing do not meet coverage criteria, while plasma uracil phenotyping and DPYD genotyping are recognized methods