RetiredCapital BluecrossPolicy AHS G2107

Measurement of Thromboxane Metabolites for ASA Resistance

Defines coverage position for measurement of thromboxane metabolites (e.g., urinary 11-dehydro-thromboxane B2, AspirinWorks) to evaluate aspirin resistance, including rationale, evidence, related policies, and applicable CPT/HCPCS codes.

Policy Summary

PayerCapital Bluecross

PolicyMeasurement of Thromboxane Metabolites for ASA Resistance

Policy CodePolicy AHS G2107

Change TypeRetirement

Effective Date

Next Review Date

Key ActionDetermine individual benefit coverage and applicable Medicare/Medicaid/local coverage determinations; government policies override this policy when in conflict.

POLICY UPDATE CHANGES

Policy status marked RETIRED on 3/1/2025.

1Primary Not-Covered Statement

2Procedure codes listed

Coverage Summary

Policy title: Measurement of Thromboxane Metabolites for ASA Resistance (Policy Number: AHS G2107). Payer: AHS. Scope summary: Defines coverage position for measurement of thromboxane metabolites (e.g., urinary 11-dehydro-thromboxane B2, AspirinWorks) to evaluate aspirin resistance, including rationale, evidence, related policies, and applicable CPT/HCPCS codes. Policy document type note: coverage_criteria; Policy retired; primary coverage position: urinary thromboxane metabolite testing for aspirin resistance not covered. Retirement status and dates: RETIRED effective 3/1/2025; initial presentation 09/18/2015; last review/retirement noted 2025-03-01. Primary coverage position: measurement of thromboxane metabolites in urine to evaluate aspirin resistance is not covered.

Policy-level key facts

policy_numberAHS G2107

statusRETIRED

subjectMeasurement of thromboxane metabolites (urine) for aspirin (ASA) resistance

last_review2025-03-01

effective_date

scope_summaryDefines coverage position for measurement of thromboxane metabolites (e.g., urinary 11-dehydro-thromboxane B2, AspirinWorks) to evaluate aspirin resistance, including rationale, evidence, and applicable CPT codes.

thresholdsAspirin effect cutoff: <1500 pg 11-dehydro-TxB2/mg creatinine

Medical Necessity / Coverage Determination

Medically Necessary / Coverage Determination

Coverage application depends on individual benefit coverage; government policies (NCD/LCD) override when applicable.

ALL of the following

Operational note: If conflict with applicable government policy (NCD/LCD/state Medicaid), government policy governs determination
Operational

Not Medically Necessary / Does Not Meet Coverage Criteria

The following does not meet coverage criteria due to lack of published scientific literature confirming test necessity and benefit:

For all indications, measurement of thromboxane metabolites in urine (e.g., AspirinWorks) to evaluate aspirin resistance DOES NOT MEET COVERAGE CRITERIA.

Not Covered / Experimental Uses

Coverage stance: Not covered (cosmetic/diagnostic testing without demonstrated benefit). Explicit primary not-covered statement: For all indications, measurement of thromboxane metabolites in urine (e.g., AspirinWorks) to evaluate aspirin resistance DOES NOT MEET COVERAGE CRITERIA. Emphasis: For all indications, urinary thromboxane metabolite testing to evaluate aspirin resistance is not covered and claims are subject to denial per this policy.

Provider Actions

Documentation Required

Check member benefit and applicable government policy

Determine the member’s specific benefit coverage and check for any applicable Medicare, Medicaid, or local coverage determinations (NCDs/LCDs/state Medicaid policies). If there is a conflict between this policy and an applicable government policy for the member, the government policy governs the coverage determination.

Denial Risk

Claims for urinary thromboxane metabolite testing for aspirin resistance

Claims for measurement of thromboxane metabolites in urine to evaluate aspirin (ASA) resistance are not covered and are subject to denial under this policy.

84431

Background, Evidence & Definitions

Background: Urinary 11-dehydro-thromboxane B2 (11‑dhTxB2) is a metabolite proposed to reflect thromboxane A2 (TxA2) generation and the pharmacologic effect of aspirin. Tests such as the AspirinWorks enzyme-linked immunoassay measure urinary Tx metabolites. Limitations include that urinary 11‑dhTxB2 is not specific to platelets (up to ~30% or more may derive from extra-platelet sources such as monocytes, macrophages, atherosclerotic plaque, and other nucleated tissues) and poor correlation with other platelet function tests. The clinical utility of using urinary thromboxane metabolites to guide therapy or classify aspirin resistance remains unproven.

Evidence item	Value
Prevalence of aspirin resistance (literature)
15%-25% (varies by assay and study)
FDA aspirin effect cutoff performance
Cutoff for aspirin effect: <1500 pg 11-dehydro-TxB2/mg creatinine; 88.2% of non-aspirin users above cutoff; 5.5% of aspirin users indicated lack of aspirin effect in pooled analysis
Systematic review finding
Poor correlation among platelet function tests; clinical usefulness to classify aspirin resistance remains undetermined

Definitions: • ASA (Aspirin): Acetylated salicylate intended to inhibit cyclooxygenase‑1 (COX‑1) and reduce thromboxane A2 production. • TxA2 / TxB2 / 11‑dehydro‑TxB2: Thromboxane A2 (TxA2) is a platelet‑activating mediator; 11‑dehydro‑thromboxane B2 is a urinary metabolite used to estimate TxA2 generation. • Aspirin resistance: Inability of aspirin to decrease platelet production of thromboxane A2 leading to platelet activation and aggregation.