Diagnosis of Idiopathic Environmental Intolerance
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Defines Blue Cross Blue Shield - Tennessee's reimbursement stance on laboratory and diagnostic testing performed to diagnose or evaluate Idiopathic Environmental Intolerance (IEI), including specific tests, panels, and sample types that do not meet coverage criteria and unit limits for certain CPT codes. Applies to covered members per benefit terms.
No material clinical or coverage changes in this revision.
Coverage Criteria for IEI Testing
Not covered tests and limitations
Tests and panels that do not meet coverage criteria for diagnosis of IEI or for asymptomatic/general screening without abnormal findings:
Specific metabolite tests with restricted uses
- Vanillylmandelic acid (VMA) testing is not covered except for diagnosis/monitoring of neuroblastoma or neuroendocrine tumors.
- Homovanillic acid (HVA) testing is not covered except for diagnosis/evaluation of neuroblastomas.
- 5-hydroxyindolacetic acid (5-HIAA) testing is not covered except for diagnosis/evaluation of carcinoid syndrome or staging/treatment/surveillance of suspected neuroendocrine tumors.
- Elastase testing is not covered except when used for pancreatic insufficiency.
Summary stance and considerations
Key clinical and guideline statements relevant to coverage decisions:
Breath testing and SIBO diagnostic considerations
- A validated gold standard for SIBO diagnosis has not been established; breath tests (lactulose or glucose substrates) detect hydrogen/methane but have limitations in sensitivity and specificity.
- Studies show lactulose breath testing may not discriminate IBS patients from healthy controls (Bratten et al., 2008) and specificity/sensitivity vary (Ghoshal et al., 2014).
- The North American Expert Consensus suggests a small-bowel culture threshold of >10^3 c.f.u./ml if culture is considered and provides conditional recommendations on the use and interpretation of breath testing for SIBO and related indications, while noting methodological limitations.
Guideline and society positions on IEI testing
- Major professional organizations have expressed skepticism about IEI (formerly MCS); AMA (1992) stated MCS should not be recognized as a syndrome without accurate, reproducible studies; AAAAI (2006) discouraged use of nonvalidated immune-based tests; ACOEM (1999) noted lack of consistent physical findings or laboratory abnormalities and recommended avoiding unnecessary tests.
Adoption/Effective Date
Administrative note regarding policy adoption:
Coding and Unit Limits
| 83918 | Organic acids; total, quantitative, each specimen — max 2 units per date of service |
| 83919 | Organic acids; qualitative, each specimen — max 1 unit per date of service |
| 83921 | Organic acid, single, quantitative — max 2 units per date of service |
| 82127 | Amino acids; single, qualitative, each specimen — max 1 unit per date of service |
| 82136 | Amino acids, 2 to 5 amino acids, quantitative, each specimen — max 2 units per date of service |
| 82139 | Amino acids, 6 or more amino acids, quantitative, each specimen — max 2 units per date of service |
| 84585 | Vanillylmandelic acid (VMA), urine — max 1 unit per date of service |
| 83150 | Homovanillic acid (HVA) — max 1 unit per date of service |
| 83497 | Hydroxyindolacetic acid, 5-(HIAA) — max 1 unit per date of service |
| 82656 | Elastase, pancreatic, fecal, qualitative or semi-quantitative — max 1 unit per date of service |
| No codes listed |
Provider Actions, Billing, and References
Provider reimbursement and clinical evaluation actions — do not submit/expect coverage for tests designed to affirm IEI; apply benefit-specific determinations
Provider reimbursement: Do not submit or expect coverage for laboratory tests designed to affirm the diagnosis of idiopathic environmental intolerance (IEI). These tests are not supported by sufficient published scientific evidence to establish clinical benefit and DO NOT MEET COVERAGE CRITERIA. Apply benefit-specific determinations; coverage decisions depend on the member's plan, and Medicare/Medicaid specifications are addressed elsewhere in the policy.
- Laboratory tests to affirm IEI — not covered
- Breath hydrogen/methane testing for IEI — not covered
Regulatory status of IEI tests — no FDA-approved tests; many are laboratory-developed tests (LDTs) regulated under CLIA
No specific U.S. Food and Drug Administration (FDA) approval or clearance for tests to diagnose idiopathic environmental intolerance (IEI) was identified. Many assays are offered as laboratory-developed tests (LDTs) that laboratories validate and perform in-house; these are regulated under CLIA as high-complexity tests. FDA clearance/approval is not currently required for clinical use of LDTs.
- No FDA-approved/cleared IEI tests found
- Many IEI-related assays are LDTs regulated under CLIA (CMS)
Provider action: References — clinical literature and vendor test pages supporting clinical background and testing discussions
Key clinical literature, consensus statements, and vendor test pages relevant to IEI, breath testing, and related laboratory panels are listed below. These sources informed the clinical background and testing discussions; vendors' test descriptions do not establish medical necessity.
- Ghoshal UC et al., Breath tests and SIBO (2014)
- Rezaie A et al., North American Consensus on Hydrogen and Methane-Based Breath Testing (2017)
- Rossi S & Pitidis A, Multiple Chemical Sensitivity review (2018)
- Schmiedchen K et al., Methodological limitations in IEI-EMF studies (2019)
- Gilbody S et al., PHQ screening meta-analysis (2007)
- Quarato M et al., Case report on IEI (2020)
- Huang PC et al., Survey on IEI-EMF (2018)
- Usai-Satta P et al., Controversy on lactulose for SIBO (2018)
- Pimentel M., SIBO clinical manifestations and diagnosis (UpToDate, 2020)
- LifeExtension. Nutrient Panel Blood Test (vendor)
- SpectraCell. Micronutrient Test Panel and SPECTROX™ (vendor)
- Vibrant. MICRONUTRIENTS (vendor)
Policy adoption note
EFFECTIVE DATE 7/1/2023 - Adopted Avalon policy recommendation.
Definitions and Abbreviations
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