ModifiedCentenePolicy N/A

Genetic Testing: Metabolic, Endocrine, and Mitochondrial Disorders - Coverage Criteria

This policy governs medical necessity and coverage criteria for genetic and molecular testing to diagnose or confirm hereditary metabolic, endocrine (non-cancer), and mitochondrial disorders for members of Centene-affiliated health plans.

Policy Summary

PayerCentene

PolicyGenetic Testing: Metabolic, Endocrine, and Mitochondrial Disorders - Coverage Criteria

Policy CodePolicy N/A

Change TypeModified criteria and operational guidance

Effective DateN/A

Next Review DateNov 1, 2025

Key ActionObtain prior authorization for listed multigene MODY panels and mitochondrial sequencing and document required diagnostic workup before approval.

SourceLink

POLICY UPDATE CHANGES

Monogenic diabetes (including MODY) criteria were changed: the age threshold for diabetes diagnosis moved from 6 months to 12 months for immediate testing consideration, the age limit for some criteria changed from 35 to 30 years, autoantibody and C-peptide language was reworded, and requirement for specific genes in panels was removed.

Known familial variant analysis criteria were moved to the policy 'Genetic Testing: General Approach to Genetic and Molecular Testing' to consolidate criteria for known familial variant tests.

MTHFR variant analysis background updated to reflect ACMG guidance and 'Confirmed 2020' notation; recommendations emphasize that MTHFR polymorphism testing should not be ordered for thrombophilia, recurrent pregnancy loss, or at-risk family members.

Recommendations from the Mitochondrial Medicine Society favor massively parallel sequencing/NGS of the mtDNA genome, tissue testing when blood is negative, heteroplasmy analysis in urine, and consideration of nuclear gene testing and mtDNA copy number testing in specific scenarios.

1MTHFR testing investigational

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Coverage Criteria

Mitochondrial genome and nuclear gene testing

Mitochondrial genome sequencing (81460), deletion/duplication testing (81465), and nuclear gene analysis for mitochondrial disorders (0417U, 81440) — coverage criteria:

ANY of the following

Medically necessary when:
- The member/enrollee has a classic phenotype of a maternally inherited mitochondrial syndrome (for example, Leber hereditary optic neuropathy, MELAS, MIDD, NARP, Kearns-Sayre syndrome/CPEO) or a phenotype consistent with a nuclear DNA–related mitochondrial disorder (for example, MNGIE).
- OR the member/enrollee has non-specific clinical features suggestive of a primary mitochondrial disorder and meets ALL of the following diagnostic workup criteria:
- ALL of the following
  - Clinical findings of at least two of the common mitochondrial features (examples include: ptosis, proximal myopathy, external ophthalmoplegia, exercise intolerance, sensorineural deafness, cardiomyopathy, optic atrophy, pigmentary retinopathy, diabetes mellitus, seizures, fluctuating encephalopathy, dementia, stroke-like episodes, migraine, ataxia, chorea, spasticity, or a history of mid- or late-pregnancy loss).
  - Conventional biochemical laboratory studies have been completed and are non-diagnostic, including at minimum: plasma or CSF lactic acid concentration; ketone bodies; plasma acylcarnitines; and urinary organic acids.
  - Additional diagnostic testing indicated by the clinical presentation (for example: fasting blood glucose, electrocardiography, neuroimaging, electromyography, echocardiography, audiology, thyroid testing, electroencephalography, exercise testing) have been completed and are non-diagnostic.
Operational notes:
- Tissue selection: if a mtDNA mutation is strongly suspected and testing in blood is negative, mtDNA assessment in another tissue (eg, skeletal muscle or urinary epithelium) is recommended to avoid missing tissue-specific mutations or low-level heteroplasmy in blood; urine heteroplasmy analysis can be more informative than blood for some variants (eg, m.3243A>G).
- Methodology: massively parallel/NGS sequencing of the entire mtDNA genome is the preferred initial approach rather than testing a limited set of pathogenic mutations; when mtDNA deletion/duplication testing is indicated, NGS methods that detect large-scale deletions/duplications are preferred.
- Copy number and depletion testing: when tissue biopsy is obtained, consider mtDNA copy number (depletion) analysis (eg, by qPCR) because depletion may not be detected in blood. mtDNA proliferation is a nonspecific finding and may not indicate primary mitochondrial disease.
- Nuclear gene testing: when multiple mtDNA deletions are identified or a nuclear-encoded mitochondrial disorder is suspected, NGS‑based nuclear gene panels with complete coverage of known mitochondrial disease genes are preferred over single‑gene testing. If no mutation is identified on targeted panels, consider whole exome sequencing.

Covered Indications

inv-31: Monogenic diabetes (MODY) multigene panels to establish or confirm diagnosis when age and clinical criteria are met.

Monogenic diabetes (MODY) multigene panels are medically necessary to establish or confirm diagnosis when age and clinical criteria are met.

MODY panel indication: Multigene MODY panel testing (e.g., CPTs 81403, 81405, 81406, 81407, 81479) is medically necessary when the member meets age‑based criteria (diagnosis within the first 12 months of life OR diagnosis before 30 years of age) and clinical features as specified in policy.

Panels are investigational for indications not meeting policy criteria.

inv-32: Mitochondrial genome sequencing/deletion/duplication and nuclear gene analysis to establish or confirm a primary mitochondrial disorder for classic phenotypes or when non-specific features plus specified diagnostic workup are met.

Mitochondrial genome sequencing (81460), deletion/duplication (81465), and nuclear gene analysis (0417U, 81440) are medically necessary to establish or confirm a primary mitochondrial disorder for classic phenotypes or when non‑specific features plus a specified diagnostic workup are met.

Classic phenotype:

Coding

Covered CPT Codes / referenced CPTsCPTCovered

81291	MTHFR targeted variant analysis (example common CPT for MTHFR)
81403	Multigene panel for monogenic diabetes / MODY (one of listed CPTs)
81405	Multigene panel for monogenic diabetes / MODY
81406	Multigene panel for monogenic diabetes / MODY
81407	Multigene panel for monogenic diabetes / MODY
81479	Unlisted molecular pathology procedure (used in panels per document)
81460	Mitochondrial genome sequencing
81465	Mitochondrial deletion/duplication testing
81440	Nuclear mitochondrial gene panel, NGS
0417U	Nuclear genes analysis / specific mitochondrial testing (listed example)

1–10 of 13

1/2

Example ICD-10 Codes referencedICD-10

E88.40	Mitochondrial metabolism disorder, unspecified
E88.41	Mitochondrial myopathy
E88.42	Mitochondrial cardiomyopathy
E88.49	Other mitochondrial disorders
G31.82	Other mitochondrial myopathy
H49.811-H49.819	Ophthalmoplegia diagnosis range referenced

Age of diabetes onset for MODY testing

Age thresholdsDiagnosis of diabetes within the first 12 months of life OR diagnosis before 30 years of age.

Clinical qualifiers for onset before 30If diagnosed before age 30, member must have at least one: autoantibody negative, retained C-peptide, or a diabetes phenotype not characteristic of type 1 or type 2.

Family history requirementWhen applicable, family history consistent with autosomal dominant inheritance must be present to support MODY panel testing for those diagnosed before age 30.

Provider Actions

Prior Authorization

Prior Authorization Required — follow general approach

Prior authorization: Requests for genetic testing described in this policy will be evaluated according to the criteria in the General Approach to Genetic and Molecular Testing policy. Prior authorization is required for multigene MODY panels and for mitochondrial genome sequencing/deletion-duplication and nuclear gene analysis when indicated by the clinical criteria in this policy.

Multigene MODY panels (e.g., 81403, 81404, 81405, 81406, 81407, 81479)
Mitochondrial genome sequencing (81460), deletion/duplication (81465), and nuclear gene analysis (81440)

Documentation Required

Documentation Required — pre-testing diagnostic workup

Documentation of pre-testing diagnostic workup must be provided with the authorization request. This should demonstrate that conventional biochemical laboratory studies were completed and were non-diagnostic, and that additional indicated diagnostic testing based on the clinical presentation was completed and non-diagnostic when required by the diagnostic criteria.

Not Covered / Investigational

MTHFR targeted variant analysis (CPT 81291) is considered investigational and not covered for all indications. Claims for this targeted MTHFR testing may be denied on the basis that the test is investigational.

MTHFR polymorphism genotyping for evaluation of thrombophilia, recurrent pregnancy loss, or for screening at‑risk family members is not supported by ACMG guidance and is therefore not covered for these indications.

Eligibility Requirements

Eligibility for monogenic diabetes (MODY) multigene panel testing requires documentation of the member’s age at diabetes onset (for example, diagnosis within the first 12 months of life or diagnosis before 30 years of age) and supporting clinical features such as autoantibody negativity, retained C‑peptide, atypical diabetes phenotype, and family history consistent with autosomal dominant inheritance when applicable.

Eligibility for mitochondrial sequencing or nuclear gene testing requires either a classic phenotype of a known maternally inherited or nuclear mitochondrial syndrome, or a non‑specific but suggestive phenotype with completed and non‑diagnostic conventional biochemical studies (e.g., plasma/CSF lactic acid, ketone bodies, plasma acylcarnitines, urinary organic acids) and any additional indicated diagnostic testing completed and non‑diagnostic.

When mitochondrial disease is suspected, documentation should include results of initial laboratory evaluation (plasma or CSF lactic acid, ketone bodies, plasma acylcarnitines, urinary organic acids) and rationale for tissue selection. If blood mtDNA testing is negative but clinical suspicion remains high, testing mtDNA from another tissue (such as muscle or urine) is recommended due to heteroplasmy.

Prior to approving mitochondrial sequencing, clinical documentation must show that conventional biochemical laboratory studies and any additional indicated diagnostic evaluations have been completed and were non‑diagnostic. This pre‑testing workup helps ensure sequencing is performed in the appropriate diagnostic context.

Definitions

MTHFR variant analysis — definition and clinical context

DefinitionTesting for methylenetetrahydrofolate reductase (MTHFR) gene variants (e.g., 677T, 1298C).

Clinical utilityThe test is generally recognized as having little clinical utility; treatment for elevated homocysteine is the same regardless of MTHFR status.

Coverage stanceMTHFR targeted variant analysis (e.g., 677T, 1298C) (81291) is considered investigational for all indications and may be denied.

Primary mitochondrial disorder — definition

DefinitionDisorders caused by dysfunction of the mitochondrial respiratory chain due to mtDNA or nuclear DNA mutations; often multisystemic with neurologic and myopathic features; maternal inheritance suggests mtDNA involvement.

Genetic etiology

Background

Hereditary metabolic disorders (inborn errors of metabolism) disrupt biochemical pathways and may be identified through newborn screening or later when symptoms present. Hereditary endocrine disorders addressed here are non‑cancer endocrine conditions. Mitochondrial disorders arise from pathogenic variants in mtDNA or nuclear DNA, are often multisystemic with neurologic and myopathic features, and may present at any age. A maternal transmission pattern (affected women transmitting to children while affected men do not) suggests mtDNA involvement. Common clinical features include ptosis, proximal myopathy, external ophthalmoplegia, exercise intolerance, cardiomyopathy, sensorineural hearing loss, diabetes, seizures, stroke‑like episodes, and high incidence of mid‑ and late‑pregnancy loss.

Non‑specific phenotype with required workup: Member has non‑specific features suggestive of mitochondrial disease AND: (1) at least two clinical features (e.g., ptosis, external ophthalmoplegia, proximal myopathy, exercise intolerance, cardiomyopathy, sensorineural deafness, optic atrophy, fluctuating encephalopathy, seizures, dementia, stroke‑like episodes, migraine, ataxia, chorea, spasticity, history of multiple late‑term pregnancy loss); (2) conventional biochemical studies completed and non‑diagnostic (plasma or CSF lactic acid, ketone bodies, plasma acylcarnitines, urinary organic acids); and (3) additional indicated diagnostic testing completed and non‑diagnostic (e.g., fasting glucose, ECG, neuroimaging, EMG, echocardiography, audiology, thyroid testing, EEG, exercise testing).

Testing is investigational when these criteria are not met.

inv-33: Genetic testing for listed rare metabolic and endocrine disorders when clinical features consistent with the disorder are present.

Genetic testing is medically necessary for the following listed rare metabolic and endocrine disorders when clinical features consistent with the disorder are present.

Listed disorders: Testing is medically necessary for disorders listed in policy (examples include congenital adrenal hyperplasia; congenital disorders of glycosylation; congenital hyperinsulinism; homocystinuria; propionic acidemia; methylmalonic acidemia; maple syrup urine disease; biotinidase deficiency; carnitine cycle disorders; Wilson disease; galactosemia; GLUT1 deficiency; phenylalanine hydroxylase deficiency; porphyria; McCune‑Albright syndrome; glycogen storage disorders including Pompe disease; Kallmann syndrome; hypophosphatasia; lysosomal storage disorders; OTC deficiency; urea cycle disorders; malignant hyperthermia; SHOX deficiency) when clinical features for the specific disorder are present or when evaluated via the General Approach policy.

List is not comprehensive; use GeneReviews/OMIM for disorder‑specific features.

inv-34: Genetic testing to establish or confirm diagnosis of metabolic, endocrine, or mitochondrial disorders not specifically discussed in other policies, when criteria of the General Approach policy are met.

Genetic testing to establish or confirm diagnosis of metabolic, endocrine, or mitochondrial disorders not specifically discussed elsewhere is covered when the General Approach policy criteria are met.

Evaluation by General Approach: Requests for testing of conditions not explicitly covered in this policy will be evaluated according to the criteria in the General Approach to Genetic and Molecular Testing policy.

Known familial variant analysis criteria were consolidated into the General Approach policy; reference that policy for familial variant requests.

inv-35: Monogenic diabetes testing for infants diagnosed <12 months (immediate) and other specialty-recommended scenarios (see policy).

Monogenic diabetes testing is recommended in several specialty‑endorsed scenarios; immediate testing is indicated for infants with early‑onset diabetes.

Infant testing: All infants diagnosed with diabetes within the first 12 months of life should have immediate genetic testing for neonatal/monogenic diabetes.age <12 months

Other specialty‑recommended scenarios: Consider testing for infants diagnosed 6–12 months, women with gestational diabetes and fasting glucose >5.5 mmol/L without obesity for GCK testing, individuals with persistent mild hyperglycemia without obesity, and young non‑obese individuals (<30 years) who are autoantibody negative and/or have retained C‑peptide.fasting glucose >5.5 mmol/L; age <30 years

Consult a diabetes genetics center for interpretation and management guidance.

Documentation Required

Monogenic Diabetes — required documentation

When requesting testing to evaluate for monogenic diabetes (including MODY), include documentation supporting age of diabetes onset and clinical features consistent with suspected monogenic etiology. Provide evidence of autoantibody negativity and/or retained C‑peptide when applicable, and family history consistent with an autosomal dominant pattern if relevant.

Age at diabetes diagnosis (e.g., <12 months, <30 years, or per guideline thresholds)
Autoantibody testing results (negative)
C‑peptide levels (demonstrating endogenous insulin production)
Family history showing successive generations affected (autosomal dominant pattern)

Documentation Required

Clinical Evaluation — initial diagnostic evaluation recommended

When a mitochondrial disorder is suspected, provide documentation of the recommended initial clinical and laboratory evaluation. This supports the medical necessity of molecular testing and helps identify the most appropriate tissue and testing strategy.

Clinical features suggestive of mitochondrial disease (e.g., ptosis, myopathy, external ophthalmoplegia, exercise intolerance, cardiomyopathy, sensorineural hearing loss, seizures, stroke‑like episodes, diabetes)
Initial labs: plasma or CSF lactic acid, ketone bodies, plasma acylcarnitines, urinary organic acids
Results of prior tissue testing or rationale for tissue selection (blood vs muscle vs urine)

Prior Authorization

Tissue Reflex for mtDNA Testing — when blood is negative but suspicion remains

If blood-based mtDNA testing is negative but clinical suspicion for a primary mitochondrial disorder remains high, reflex testing of alternate tissues is recommended. Consider sequencing mtDNA from skeletal muscle or urine epithelial cells and perform heteroplasmy analysis when appropriate to improve detection of tissue-specific or low-level variants.

Reflex tissues: skeletal muscle biopsy or urinary epithelial cells
Consider heteroplasmy analysis and mtDNA copy number testing when indicated
Note that some mtDNA variants (e.g., large deletions, MELAS-associated m.3243A>G) may be undetectable in blood but detectable in other tissues