CurrentAmbetter NevadaPolicy CP.MP.121

Homocysteine Testing

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This policy governs the medical necessity and coding considerations for homocysteine testing. Testing is covered for suspected homocystinuria caused by cystathionine beta-synthase deficiency when specified clinical findings or family history are present; other listed indications are not medically necessary because improved outcomes have not been established.

Policy Summary

PayerAmbetter Nevada

PolicyHomocysteine Testing

Policy CodePolicy CP.MP.121

Change TypeAnnual reviewno material clinical or coverage changes

Effective DateOct 1, 2026

Last ReviewMar 1, 2026

Next Review DateN/A

Key ActionFor Medicare members, providers must review all applicable Medicare coverage guidance before applying this policy.

SourceLink

POLICY UPDATE CHANGES

The March 2026 annual review updated references and documented external specialist review.

Earlier policy revisions expanded medically necessary criteria to include a first-degree relative with homocystinuria, markedly elevated serum and urine homocysteine, and specified characteristic physical findings.

Dementia was added as a not medically necessary indication in an earlier revision.

1Covered primary indication

6Supporting physical findings

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CurrentAmbetter NevadaPolicy CP.MP.121

Homocysteine Testing

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Sign up for Ambetter Nevada Policy CP.MP.121 alerts

Get alerted when Policy CP.MP.121 changes without checking for updates manually.

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Policy Summary

PayerAmbetter Nevada

PolicyHomocysteine Testing

Policy CodePolicy CP.MP.121

Change TypeAnnual reviewno material clinical or coverage changes

Effective DateOct 1, 2026

Last ReviewMar 1, 2026

Next Review DateN/A

Key ActionFor Medicare members, providers must review all applicable Medicare coverage guidance before applying this policy.

SourceLink

POLICY UPDATE CHANGES

The March 2026 annual review updated references and documented external specialist review.

Dementia was added as a not medically necessary indication in an earlier revision.

1Covered primary indication

6Supporting physical findings

Coverage Criteria

Medically necessary testing

Covered as medically necessary when suspected homocystinuria caused by cystathionine beta-synthase deficiency is present and at least one supporting criterion is met.

Covered homocysteine testing

At least one supporting criterion
- Family history or laboratory finding
  - A first-degree relative has homocystinuria.
  - Serum and urine homocysteine are markedly elevated.
- Characteristic physical findings
  - Developmental delay is present.
  - Marfanoid appearance is present.
  - Osteoporosis is present.
  - Ocular abnormalities, including ectopia lentis, are present.
  - Thromboembolic disease is present.
  - Severe premature atherosclerosis is present.

Not medically necessary or unproven indications

Homocysteine testing has not been proven to improve outcomes compared to other technologies for the following indications.

Not medically necessary or unproven indication

Cardiovascular risk testing.
Testing for borderline vitamin B12 deficiency.
Testing for dementia.
Testing for idiopathic (unprovoked) venous thromboembolism, recurrent venous thromboembolism, thrombosis occurring at less than 45 years of age, or thrombosis at an unusual site.
Testing for all other conditions.

Cardiovascular risk testing is not medically necessary. Homocysteine testing has not been proven to improve outcomes compared with other technologies for this indication.

Testing for borderline vitamin B12 deficiency is not medically necessary. Homocysteine testing has not been proven to improve outcomes compared with other technologies for this indication.

Testing for dementia is not medically necessary. Homocysteine testing has not been proven to improve outcomes compared with other technologies for this indication.

Testing is not medically necessary for idiopathic or unprovoked venous thromboembolism, recurrent venous thromboembolism, thrombosis occurring at less than 45 years of age, or thrombosis at an unusual site because improved outcomes have not been proven.

Testing for all other conditions is not medically necessary because homocysteine testing has not been proven to improve outcomes compared with other technologies.

Coding

CPTCPT

83090

Homocysteine

Not Medically Necessary ICD-10 CodesICD-10Not Covered

F01.511	Vascular dementia, unspecified severity, with agitation
F01.518	Vascular dementia, unspecified severity, with other behavioral disturbance
F01.52	Vascular dementia, unspecified severity, with psychotic disturbance
F01.53	Vascular dementia, unspecified severity, with mood disturbance
F01.54	Vascular dementia, unspecified severity, with anxiety
F01.A4	Vascular dementia, mild, with anxiety
F01.B4	Vascular dementia, moderate, with anxiety
F01.C4	Vascular dementia, severe, with anxiety
F03.9	Unspecified dementia, unspecified severity
F03.A4	Vascular dementia, mild, with anxiety

1–10 of 29

1/3

Basal Homocysteine

CategoryBasal homocysteine

Concentration range5 to 15 μmol/L

Clinical classificationHomeostatic or basal homocysteine concentration

Moderate Hyperhomocysteine

CategoryModerate hyperhomocysteine

Concentration range15 to 30 μmol/L

Clinical classificationModerate hyperhomocysteine concentration

Provider Actions

Denial Risk

Avoid noncovered indications

Do not order homocysteine testing for cardiovascular risk testing, borderline vitamin B12 deficiency, dementia, idiopathic or unprovoked venous thromboembolism, recurrent venous thromboembolism, thrombosis occurring at less than 45 years of age, thrombosis at an unusual site, or other conditions. Testing for these indications is not medically necessary because improved outcomes have not been proven compared with other technologies; claims may be denied.

Clinical Background

Homocysteine is an intermediary amino acid generated during the conversion of methionine to cysteine. Homocystinuria is a rare inherited condition associated with severe elevations in plasma and urine homocysteine. Mutations affecting cystathionine beta-synthase can cause excess homocysteine and premature thrombotic events. Homocysteine levels are also influenced by folate and vitamins B6 and B12.

Definitions

Homocystinuria

DefinitionA rare inherited condition associated with inability to properly produce or metabolize methionine.

Homocysteine findingsSevere elevations in plasma and urine homocysteine concentrations.

Metabolic associationMutations in cystathionine beta-synthase, a key enzyme in the transsulfuration pathway, are associated with excess homocysteine levels.

Clinical associationCystathionine beta-synthase mutations are associated with premature thrombotic events.

Hyperhomocysteine Concentration Categories

Basal5 to 15 μmol/L

Moderate hyperhomocysteine

Covered Indications

Suspected homocystinuria caused by cystathionine beta-synthase deficiency

Homocysteine testing is medically necessary for suspected homocystinuria caused by cystathionine beta-synthase deficiency when at least one of the following is present.

Suspected cystathionine beta-synthase deficiency

Supporting clinical or laboratory feature
- A first-degree relative has homocystinuria.
- Serum and urine homocysteine are markedly elevated.
- Characteristic physical finding
  - Developmental delay.

Not Covered

Homocysteine testing is not medically necessary for cardiovascular risk testing, borderline vitamin B12 deficiency, dementia, idiopathic or recurrent venous thromboembolism, thrombosis occurring before age 45 or at an unusual site, or testing for all other conditions.