CurrentBlue Cross Blue Shield - TennesseePolicy N/A

Diabetes Mellitus Testing (FPG, OGTT, A1c) Coverage Criteria

Coverage and limitations for laboratory testing used to screen, diagnose, and monitor diabetes mellitus and prediabetes (fasting plasma glucose, oral glucose tolerance test, and hemoglobin A1c) for BlueCross BlueShield of Tennessee members.

Policy Summary

PayerBlue Cross Blue Shield - Tennessee

PolicyDiabetes Mellitus Testing (FPG, OGTT, A1c) Coverage Criteria

Policy CodePolicy N/A

Change TypeNo material changes

Effective DateN/A

Next Review DateN/A

Key ActionUse the correct CPT for A1c testing (83036 for lab-based, 83037 for point-of-care/home device) and document the test method to support billing.

SourceLink

POLICY UPDATE CHANGES

No material clinical or coverage changes in this revision.

Every 3 yearsAsymptomatic ≥35 screening interval

Every 3 yearsAdults with risk factors screening

AnnualPrediabetes screening

AnnualA1c allowed for monitoring

2004-2024References span

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Coverage Criteria — Indications, Frequencies, and Limitations

Covered indications and screening frequencies

Covered when the conditions below are met according to specified populations and situations.

Symptoms and diagnosis: Measurement of plasma glucose meets coverage for individuals with acute or persistent classic symptoms of diabetes mellitus.

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Established diabetes monitoring: For individuals with a diagnosis of type 1 or type 2 diabetes, measurement of hemoglobin A1c meets coverage in any of the following situations; no coverage limit applies — frequency follows clinical need (e.g., semiannual if stable, quarterly if not meeting goals or therapy changes).

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Prediabetes screening: For prediabetic individuals, annual screening for type 2 diabetes with a fasting plasma glucose test or measurement of hemoglobin A1c meets coverage.annual

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Asymptomatic adults >=35 without risk factors: Asymptomatic individuals 35 years of age or older with no risk factors: screening once every three years with a fasting plasma glucose test meets coverage.every 3 years

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Adults >=18 with risk factors: Individuals 18 years of age or older with any listed risk factors: screening once every three years for prediabetes or type 2 diabetes with a fasting plasma glucose test or measurement of hemoglobin A1c meets coverage.every 3 years

risk factors enumerated in [[chunk 3]]

HIV-positive individuals: For individuals positive for HIV, screening for diabetes and prediabetes with a fasting plasma glucose test meets coverage when starting antiretroviral therapy (ART), when switching ART, 3–6 months after starting or switching ART, and annually when initial screening was normal.3-6 months and annual

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Cystic fibrosis: Individuals age 10 years and older with cystic fibrosis (without cystic fibrosis–related diabetes): annual screening for CF-related diabetes with an OGTT meets coverage.annual

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Pediatrics overweight/obese: Overweight or obese individuals younger than 18 years: screening once every three years with a fasting plasma glucose test, an OGTT, or measurement of hemoglobin A1c meets coverage when specified risk factors are present.every 3 years

risk factors enumerated in [[chunk 4]]

Pregnancy screening: Pregnant individuals: a fasting plasma glucose test or an OGTT up to once per month during pregnancy meets coverage.up to monthly

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Gestational diabetes postpartum: For individuals diagnosed with gestational diabetes mellitus (GDM): an OGTT meets coverage to screen for persistent diabetes or prediabetes 4–12 weeks postpartum, and to repeat screening to confirm a diagnosis if the initial postpartum screen is positive.4-12 weeks postpartum

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Not medically necessary / Not covered

Not covered / does not meet criteria

Wellness visit with no abnormal findings: Fasting plasma glucose testing at a wellness visit with no abnormal findings does NOT meet coverage criteria.

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A1c not meeting other criteria: Measurement of hemoglobin A1c does NOT meet coverage criteria for situations not described in the policy (see Note 2).

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Measurement of hemoglobin A1c (A1c) is unreliable in conditions that affect red blood cell turnover. The policy specifies that A1c testing should not be performed in individuals with conditions associated with increased red blood cell turnover, including but not limited to sickle cell disease, recent blood transfusion, hemodialysis, or receipt of erythropoietin therapy. These situations can distort the proportion of glycated hemoglobin and lead to inaccurate A1c results; providers should use alternative methods (for example, plasma glucose measurement or fructosamine) when monitoring or diagnosing glycemia in these patients.

Fasting plasma glucose testing performed at a routine wellness visit when there are no abnormal findings does NOT meet coverage criteria. The policy explicitly states that FPG at an asymptomatic wellness visit with no abnormal findings is not covered and may be denied if billed for that context.

Measurement of hemoglobin A1c only meets coverage as described elsewhere in this policy; for all other situations not previously described, A1c testing does NOT meet coverage criteria. Note exceptions and the policy allowance of one A1c per calendar year for individuals without a diabetes diagnosis (CPT codes 83036 and 83037); for diagnosed diabetes there is no frequency limit and monitoring frequency should follow clinical need.

Procedure and Diagnostic Codes

Referenced CPT CodesCPT

82947	Glucose; quantitative, blood (except reagent strip).
82951	Glucose; tolerance test (GTT), 3 specimens (includes glucose)

Referenced CPT Codes (continued)CPT

82952	Glucose; tolerance test, each additional beyond 3 specimens.
82985	Glycated protein.
83036	Hemoglobin; glycosylated (A1C).
83037	Hemoglobin; glycosylated (A1C) by device cleared by FDA for home use.

Diagnostic thresholds

Fasting plasma glucose (FPG)Diagnostic cutoff for diabetes: ≥126 mg/dL.

2-hour Oral Glucose Tolerance Test (OGTT)Diagnostic cutoff for diabetes after 75 g load: ≥200 mg/dL.

Hemoglobin A1c (A1c) risk rangeA1c 5.7% to <6.5% indicates increased risk/prediabetes; A1c ≥6.5% generally used to diagnose diabetes.

Provider Actions, Documentation, and Billing Guidance

Billing Rule

Procedure codes referenced — codes provided for reference

Procedure codes are referenced in the source for clinician billing and must be used accurately according to test method and setting. Examples from the source: CPT 83036 (laboratory-based, delayed results) and CPT 83037 (point-of-care, immediate results). Use the code that matches where and how the test was performed; consolidated code lists appear elsewhere in the policy for reference only.

CPT 83036 — lab-based hemoglobin A1c (delayed results)
CPT 83037 — point-of-care hemoglobin A1c (immediate results)

Note

Prior authorization not specified in bibliography

No prior authorization or prior-auth requirement is specified in the bibliography or references provided. The reference list and source content do not impose prior authorization conditions — verify plan-specific benefit documents for any PA requirements.

Background — Disease and Test Overview

Diabetes mellitus encompasses heterogeneous disorders that produce hyperglycemia through progressive loss of pancreatic β‑cell mass and/or function, influenced by genetic and environmental factors. Diagnostic and screening tools referenced in this policy include fasting plasma glucose (FPG), the oral glucose tolerance test (OGTT), and hemoglobin A1c (A1c). An FPG ≥126 mg/dL or a 2‑hour OGTT result ≥200 mg/dL establishes diabetes in an asymptomatic individual, while A1c reflects average glycemia over the prior 8–12 weeks and helps with screening, diagnosis, and monitoring of diabetes and prediabetes.

Definitions and Standardization

Fasting plasma glucose (FPG)

DefinitionFasting plasma glucose (FPG) is blood glucose obtained after a typically overnight period of not eating (fast).

Diagnostic thresholdIn an asymptomatic individual, FPG ≥126 mg/dL establishes a diagnosis of diabetes.

UsageUsed as an affordable diagnostic alternative to A1c; commonly applied in diagnosis of type 2 diabetes.

Oral glucose tolerance test (OGTT)

DefinitionOral glucose tolerance test (OGTT) assesses 2‑hour plasma glucose after ingestion of a concentrated 75 g glucose solution (commonly used in pregnancy).

Diagnostic thresholdA 2‑hour plasma glucose value ≥200 mg/dL during a 75 g OGTT establishes a diagnosis of diabetes in an asymptomatic individual.