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Serum Testing For Evidence of Mild Traumatic Brain Injury
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Defines Oscar Health's coverage stance for serum (and other fluid) biomarker tests used to evaluate mild traumatic brain injury (mTBI)/concussion for members; applies to providers submitting claims under Oscar reimbursement rules.
No material clinical or coverage changes in this revision.
Coverage Criteria — Serum Biomarker Testing for mTBI
inv-01: Not Medically Necessary — Biomarker testing for mTBI
Not covered when ALL of the following are met:
Document explicitly states these tests do not meet criteria for mTBI evaluation.
Document explicitly names panels and platforms as not meeting criteria.
inv-02: Guideline-derived clinical contexts
Guideline statements relevant to clinical use of serum biomarkers in mTBI evaluation:
Level C statement; ACEP suggests potential to combine biomarkers with clinical decision rules.
Specific caution for pediatric use.
Applies to VA/DoD practice guideline for concussion/mTBI.
Supports adjunctive use in adults when combined with CT decision rules.
This policy defines Oscar Health's coverage stance for serum and other fluid biomarker testing used to evaluate mild traumatic brain injury (mTBI). Measurement of concussion markers such as S100B, GFAP, and UCH-L1 in blood, saliva, or cerebrospinal fluid for the evaluation of mild TBI does not meet criteria. Similarly, panels designed to measure biomarkers of TBI (for example, i-STAT TBI Plasma and Alinity® i TBI) do not meet criteria and are excluded from coverage for mTBI evaluation.
Guideline statements referenced in the policy convey mixed recommendations about clinical biomarker use and emphasize limited evidence and population-specific caution. The American College of Emergency Physicians (ACEP) has described potential contexts where S100B may inform CT decisions in adults, but overall availability and strength of evidence are limited. The Centers for Disease Control and Prevention (CDC) has stated that biomarkers should not be used outside research settings to diagnose children with mTBI. The American Academy of Pediatrics notes multiple biomarkers have been investigated but reports they have not been incorporated into routine pediatric clinical practice. The American College of Surgeons and other surgical bodies describe circumstances in adults (GCS 13–15, clinician-assessed low but nonzero risk) where GFAP, UCH-L1, and S100B may be considered adjuncts to rule out CT imaging when combined with decision rules; these recommendations are framed as adjunctive rather than definitive diagnostic criteria.
Evidence cited in the policy highlights limitations in the reliability and specificity of some biomarkers across populations. For example, a study concluded that S100B is not a reliable prognostic index in pediatric TBI, and other work demonstrates that high serum S100B can occur in trauma patients without head injuries, reducing its specificity. Comparative studies cited show GFAP may outperform S100B for detecting traumatic intracranial lesions on CT, illustrating variable performance across markers and clinical contexts.
For clarity, the policy explicitly states that use of serum (and other fluid) biomarker tests for the evaluation of mild TBI does not meet criteria and therefore is considered not medically necessary for this indication. Claims submitted for measurement of these concussion biomarkers or for panels intended to measure TBI biomarkers may be denied.
The Veterans Administration and Department of Defense practice guideline recommends against using serum biomarkers to establish the diagnosis of mTBI or to direct care (except for patients with indicators for immediate referral). The guideline explicitly lists serum biomarkers including S100B, GFAP, and UCH-L1 among tests it suggests should not be used for diagnosis or clinical routing in their practice context.
The policy excerpts cite guideline statements and studies that describe variable diagnostic and prognostic performance of biomarkers rather than making nuanced coverage exceptions. In other words, the document summarizes evidence showing inconsistent sensitivity, specificity, and population-dependent reliability (for example, pediatric limitations and extracranial elevations of S100B) but does not offer conditional coverage pathways; these citations support the policy's decision to exclude biomarker testing for routine mTBI evaluation.
Coding — Tests, Platforms, and Procedure Codes
| i-STAT™ Alinity™ / Alinity® i TBI | Platform/tests measuring GFAP and UCH-L1 (product names mentioned in document) |
| 83516 | Immunoassay for analyte other than infectious agent antibody or infectious agent antigen; qualitative or semiquantitative, multiple step method. |
| 84999 | Unlisted chemistry procedure. |
| 0570U | Neurology (traumatic brain injury), analysis of glial fibrillary acidic protein (GFAP) and ubiquitin carboxyl-terminal hydrolase L1 (UCHL1), immunoassay, whole blood or plasma, individual components reported with the overall result of elevated or non-elevated based on threshold comparison. Proprietary test: i-STAT TBI Lab/Manufacturer: Abbott Point of Care |
| No codes listed |
Provider Actions — Authorization, Billing, and Documentation
Verify member benefits and authorization requirements
Coverage depends on the member’s benefit plan and medical necessity/authorization determinations; apply the policy criteria only after verifying the member’s current benefits and any applicable Medicare/Medicaid specifications.
- Application of criteria is dependent upon an individual's benefit coverage at the time of the request (III. Indications and/or Limitations of Coverage).
- Oscar’s reimbursement policies do not guarantee reimbursement; services must meet authorization and medical necessity guidelines for the procedure, diagnosis, and member's state of residence (Important Note).
No prior-auth process specified in policy — confirm with plan
The policy text does not state any specific prior authorization process or requirement for serum biomarker testing; verify any prior authorization requirements with the member’s benefit plan or standard lab test prior authorization rules before ordering.
- This excerpt does not specify any prior authorization requirements for serum biomarker testing.
Policy states these tests do not meet criteria for mTBI
Providers must be aware that these biomarker tests are designated as not meeting criteria for evaluation of mild TBI; ordering or billing for these services may be reviewed against the policy.
- Measurement of concussion markers (S100B, GFAP, UCH-L1) in blood, saliva, or CSF DOES NOT MEET CRITERIA for evaluation of mild TBI.
- Panels designed to measure biomarkers of TBI (e.g., i-STAT TBI Plasma, Alinity® i TBI) DO NOT MEET CRITERIA.
No step therapy requirements described
No step therapy or prerequisite testing requirements are described in this policy; do not assume step-therapy sequencing is required unless the member’s benefit plan specifies otherwise.
- No step therapy requirements are described in this portion of the policy.
Submit accurate documentation and correct codes
Providers are responsible for submitting accurate and complete documentation and for appropriate coding; failure to follow coding/billing guidelines may result in denial or recoupment.
- Claims should be coded appropriately according to industry standard coding guidelines (CPT, HCPCS, ICD-10, CMS guidance).
- If coding/billing guidelines or current reimbursement policies are not followed, Oscar may deny the claim and/or recoup payment.
Attach supporting evidence/references when justifying testing
Include references and supporting evidence when documentation is needed for medical necessity determinations or peer review; the policy provides an evidence list that may be used to support claims.
- Policy includes an extensive Evidence-based Scientific References section (e.g., Takala RS; Korley FK; VA/DoD and CDC guidance).
- References may be required to support medical necessity determinations.
Claims for these biomarker tests may be denied
Claims for measurement of concussion biomarkers (S100B, GFAP, UCH-L1) or panels (e.g., i-STAT TBI Plasma, Alinity® i TBI) are not covered per this policy and may be denied if submitted as medically necessary services for mTBI evaluation.
- Measurement of concussion markers in blood, saliva, and/or CSF DOES NOT MEET CRITERIA for evaluation of mild TBI.
- Panels designed to measure biomarkers of TBI DO NOT MEET CRITERIA and may be denied if billed as medically necessary services.
Government coverage rules supersede policy when conflicting
If this policy conflicts with applicable government policy (e.g., Medicare LCD/NCD or state Medicaid), the government policy governs determinations and may lead to different authorization or denial outcomes.
- Government policies (LCDs/NCDs or state Medicaid) will control in the event of a conflict with this policy.
No explicit denial triggers listed — but medical necessity and coding failures can cause denial
This section does not list specific denial triggers (e.g., missing documentation or clinical thresholds); however, absence of medical necessity per the policy and failure to follow coding/billing guidelines remain actionable causes for denial.
- No explicit denial triggers are listed in this section of the document.
- Claims may still be denied for failure to meet medical necessity criteria or for improper coding/billing under standard guidelines.
Background — Traumatic Brain Injury and Biomarkers
Traumatic brain injury (TBI) encompasses a spectrum of injuries caused by external forces; mild TBI (concussion) represents the majority of cases and is primarily diagnosed by clinical assessment and selective imaging. Many mild TBIs do not have CT-detectable lesions. Blood-based biomarkers (notably S100B, GFAP, and UCH-L1) have been investigated as diagnostic and prognostic adjuncts, but the literature and guideline statements cited in this policy identify concerns about specificity, variable performance across populations (including pediatric patients), and insufficient evidence to support routine clinical use for diagnosis or prognosis. These limitations underlie the policy's conclusion that biomarker measurement does not meet criteria for evaluation of mild TBI.
Definitions and Abbreviations
Revision History
Policy effective date set to 2026-10-01.
Policy last reviewed on 2026-06-16.
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