Blue Cross Blue Shield - Tennessee A1c FPG OGTT Coverage | OpenPayer
Currentblue cross blue shield - tennesseePolicy N/A
Diabetes mellitus testing (A1c, FPG, OGTT)
Coverage and clinical guidance for use of hemoglobin A1c, fasting plasma glucose (FPG), and oral glucose tolerance testing (OGTT) for diagnosis, screening, and monitoring of diabetes mellitus and prediabetes for Blue Cross Blue Shield - Tennessee members.
Policy Summary
Payerblue cross blue shield - tennessee
PolicyDiabetes mellitus testing (A1c, FPG, OGTT)
Policy CodePolicy N/A
Change TypeNo material change noted
Effective DateN/A
Next Review DateN/A
Key ActionDocument clinical indication and ensure A1c is performed using an NGSP‑certified, DCCT‑standardized method; use OGTT/FPG where A1c is unreliable.
No material clinical or coverage changes in this revision.
≥6.5%A1C diagnostic threshold
≥126 mg/dLFPG diagnostic threshold
≥200 mg/dL2‑hr OGTT diagnostic threshold
100–125 mg/dLPrediabetes (IFG) range
Twice yearly/QuarterlyMonitoring cadence
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5 codes
Referenced procedure codes
Coverage Criteria
Covered indications
Covered when any of the following condition-specific or indication-specific criteria are met:
Symptomatic diagnosis: Measurement of fasting plasma glucose for individuals with acute or persistent classic symptoms of diabetes mellitus
See Note 1 regarding clinical use
A1c in diagnosed diabetes: Measurement of hemoglobin A1c meets coverage when used for individuals with a diagnosis of Type 1 or Type 2 diabetes mellitus for baseline at initial diagnosis, twice-yearly if meeting goals and stable, quarterly if not meeting goals, or quarterly after pharmacologic therapy changes
Reimbursement policy specifies monitoring cadence
Prediabetes screening: Annual screening for type 2 diabetes with a fasting plasma glucose test or measurement of hemoglobin A1c in individuals with prediabetes
If initial screen normal, follow intervals recommended by guidelines
Risk-based adult screening: For individuals ≥18 years, screening once every 3 years with fasting plasma glucose or A1c for those with risk factors (overweight/obese; first-degree relative with diabetes; history of cardiovascular disease; hypertension; hypercholesterolemia; metabolic syndrome; acanthosis nigricans; PCOS; prior GDM)
Repeat sooner with symptoms or change in risk
HIV and ART-related screening: For people with HIV, fasting plasma glucose screening meets coverage when starting or switching antiretroviral therapy, 3–6 months after start/switch, and annually if initial screen was normal
Per ADA guidance captured in policy
Cystic fibrosis screening: For individuals ≥10 years with cystic fibrosis (without CF-related diabetes), annual OGTT screening meets coverageage >=10
A1c is not recommended as a screening test for CFRD
Pediatric overweight/obese screening: For overweight/obese children after puberty or ≥10 years, screening with fasting plasma glucose or OGTT once every 3 years when family or maternal history or other risk factors presentage >=10 or postpubertal
Follow pediatric risk-based recommendations
Pregnancy screening: For pregnant individuals, fasting plasma glucose or OGTT up to once per month during pregnancy meets coverage; for those diagnosed with GDM, OGTT meets coverage for 4–12 weeks postpartum screening and repeat confirmatory testing if initial postpartum screen positivepregnancy: as clinically indicated; postpartum 4–12 weeks
OGTT preferred postpartum; see gestational criteria for details
Screening for prediabetes and type 2 diabetes (ADA-based)
Covered when meeting ADA screening guidance:
Adult screening: Testing recommended for adults beginning at age 35; consider testing adults of any age with overweight/obesity (BMI ≥25 kg/m2 or ≥23 kg/m2 in Asian Americans) who have one or more risk factorsage >=35 or BMI criteria
If normal, repeat at minimum every 3 years
Risk factors warranting testing: First-degree relative with diabetes; high-risk race/ethnicity; history of cardiovascular disease; hypertension (>=140/90 mm Hg or on therapy); HDL <35 mg/dL and/or triglycerides >250 mg/dL; women with PCOS; physical inactivity; conditions associated with insulin resistancepresence of >=1 risk factor
People with prediabetes should be tested yearly
Cystic fibrosis-related diabetes (CFRD) screening
Covered when ALL of the following are met:
CFRD annual OGTT: Annual OGTT screening beginning by age 10 in all patients with cystic fibrosis not previously diagnosed with cystic fibrosis-related diabetesage >=10
A1c is not recommended as a screening test for CFRD
Gestational diabetes screening and early pregnancy assessment
Covered according to ADA pregnancy guidance:
Preconception or early pregnancy testing: Before 15 weeks' gestation, test women with risk factors for undiagnosed diabetes; consider testing all women at the first prenatal visit using standard diagnostic criteria<15 weeks gestation
Screen early abnormal glucose metabolism using fasting glucose 110–125 mg/dL or A1c 5.9–6.4%
Routine GDM screen: Screen for gestational diabetes at 24–28 weeks in pregnant women not previously found to have diabetes or high-risk abnormal glucose metabolism detected earlier24–28 weeks gestation
OGTT remains primary diagnostic test; A1c alone is insufficient to replace OGTT but may be used in a combined rule-out strategy
Coverage and clinical criteria
Coverage recommendations and diagnostic criteria referenced from guideline sources:
General diagnostic criteria for diabetes (AACE/ADA/NACB): Diagnosis of diabetes mellitus requires either: FPG ≥126 mg/dL after ≥8 hours fasting OR 2-h PG ≥200 mg/dL after 75-g OGTT OR random PG ≥200 mg/dL with symptoms OR A1C ≥6.5%. Diagnosis requires two abnormal test results (same sample or two separate days) unless symptomatic hyperglycemia with random PG ≥200 mg/dL confirms diagnosis.see thresholds
Grade A; BEL 2 and expert opinion noted by AACE
Screening intervals and populations: - Screen adults per USPSTF/ADA: nonpregnant adults beginning at age 35 and those with overweight/obesity; repeat at minimum every 3 years if normal. - AACE: screen ≥45 years or earlier with risk factors; repeat every 3 years if normal; consider annual testing for patients with ≥2 risk factorsscreening intervals commonly 2–3 years
Multiple guideline sources captured
Gestational diabetes testing:
Screening eligibility
AACE inclusion criteria for who should be screened for prediabetes or type 2 diabetes
Screening candidates: Individuals meeting any of the following: age ≥45 years without other risk factors; history of cardiovascular disease or family history of T2D; overweight or obese; sedentary lifestyle; member of an at-risk racial/ethnic group (Asian, African American, Hispanic, Native American, Pacific Islander); HDL-C <35 mg/dL and/or triglycerides >250 mg/dL; impaired glucose tolerance or fasting glucose and/or metabolic syndrome; PCOS, acanthosis nigricans, or NAFLD; hypertension (>140/90 mm Hg or on therapy); history of gestational diabetes or delivery of baby >4 kg; antipsychotic therapy; chronic glucocorticoid exposure; sleep disorders with prior glucose intolerance (A1C >5.7%, IGT, or IFG)see node text
Repeat testing at least every 3 years if normal; consider annual screening for patients with ≥2 risk factors.
Diagnostic criteria
Diagnostic criteria and confirmation requirements
Diabetes diagnosis: Diagnosis based on FPG ≥126 mg/dL, or 2-hour PG ≥200 mg/dL after 75-g OGTT, or random PG ≥200 mg/dL with hyperglycemia symptoms, or A1C ≥6.5%.diagnostic cutoffs as listed
Diagnosis requires two abnormal test results from the same sample or different days unless glucose ≥200 mg/dL with symptoms (single test confirms).
Prediabetes identification: Prediabetes identified by IFG 100–125 mg/dL, IGT 140–199 mg/dL at 2 hours after 75-g OGTT, and/or A1C 5.7–6.4%.prediabetes ranges as listed
A1C should be used only for screening for prediabetes; confirm diagnosis with glucose testing.
Gestational diabetes
Gestational diabetes screening and diagnostic approaches
GDM screening timing: Screen all pregnant women at 24–28 weeks' gestation.24–28 weeks
Universal screening recommended.
GDM diagnostic methods: Either one-step 75-g 2-hour OGTT with thresholds (FPG ≥92 mg/dL, 1-hour ≥180 mg/dL, 2-hour ≥153 mg/dL) OR two-step approach: 50-g 1-hour screen (threshold 130 or 140 mg/dL) followed by 3-hour 100-g OGTT with diagnostic thresholds (FPG ≥95 mg/dL, 1-hour ≥180 mg/dL, 2-hour ≥155 mg/dL, 3-hour ≥140 mg/dL)as listed
Diagnosis on two or more abnormal values for the 100-g OGTT.
Measurement of hemoglobin A1cdoes not meet coverage criteria when performed in pregnant individuals who do not already have a diagnosis of diabetes. The policy also excludes routine A1c measurement for individuals under 18 years of age who are not already diagnosed with diabetes, when performed in conjunction with fructosamine, or in people with conditions that cause increased red blood cell turnover (for example, sickle cell disease, hemodialysis, recent blood loss or transfusion, or erythropoietin therapy).
Hemoglobin A1c is not a reliable screening tool for certain dysglycemias associated with cystic fibrosis. Multiple studies show poor diagnostic accuracy of A1c compared with the 2-hour OGTT for cystic fibrosis–related prediabetes and diabetes (including INDET, IFG, and IGT), and A1c is not recommended as the screening test for CFRD. Annual OGTT beginning by age 10 years is the preferred screening approach for people with cystic fibrosis.
Point-of-care (POC) HbA1c assays are not sufficiently accurate for use in diagnosing diabetes and therefore should not be used alone for diagnostic purposes. Diagnostic A1c testing should be performed using an NGSP‑certified, DCCT‑traceable method in an accredited laboratory and laboratories should participate in proficiency testing; if POC methods are used for any diagnostic intent, results should be confirmed with a validated laboratory measure.
Due to physiological changes in pregnancy that affect glycated hemoglobin, A1c should not be used for gestational diabetes (GDM) screening or diagnosis of diabetes in pregnancy. Blood glucose–based testing (FPG or OGTT) remains the primary diagnostic approach in pregnancy; if A1c is measured in pregnancy it should not be relied upon alone for GDM diagnosis.
Outside the specific covered indications listed in this policy, measurement of hemoglobin A1c does not meet coverage criteria. For any clinical situation not explicitly described under the policy’s covered indications (for example, routine A1c measurement in non‑diagnosed, low‑risk individuals), the test is considered not covered.
Using HbA1c alone as the sole diagnostic test to replace an oral glucose tolerance test (OGTT) for gestational diabetes is not supported by the evidence because A1c lacks sufficient sensitivity and specificity in pregnancy. Some authors suggest A1c could be part of a combined rule‑out strategy with OGTT, but it should not substitute for OGTT as the definitive diagnostic test in pregnancy.
Use of point‑of‑care A1c assays alone for diabetes diagnosis is not recommended and may be considered inappropriate for diagnostic claims. The policy specifies that diagnostic A1c testing should utilize NGSP‑certified, laboratory‑based methods traceable to the DCCT reference; POC results, if used, require confirmation with a validated laboratory measure.
Coding and Diagnostic Thresholds
Applicable procedure codes referencedCPT
82951
Glucose; tolerance test (GTT), 3 specimens (includes glucose).
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.
inv-17: Diagnostic thresholds
A1C (HbA1c)≥6.5% — diagnostic threshold for diabetes; reflects average glycemia over preceding 8–12 weeks
Fasting plasma glucose (FPG)≥126 mg/dL after ≥8 hours fasting — diagnostic threshold for diabetes
Impaired fasting glucose (IFG)100–125 mg/dL — prediabetes range
Impaired glucose tolerance (IGT)2-hour PG 140–199 mg/dL after 75-g OGTT — prediabetes range
inv-18: Pregnancy A1c thresholds for early abnormal glucose metabolism
Provider Actions and Documentation
Documentation Required
Cystic Fibrosis‑Related Diabetes Screening Method
Annual screening for cystic fibrosis-related diabetes should be performed with an oral glucose tolerance test (OGTT) beginning by age 10 in patients with cystic fibrosis who do not have CF-related diabetes. Hemoglobin A1c is not recommended as a screening test for CF-related diabetes.
Begin annual OGTT screening by age 10 for CF patients without CFRD
A1c should not be used for CFRD screening
Billing Rule
Procedure Code Reference
Procedure codes are provided for reference and may not be all‑inclusive. Use payer-specific billing guidance when submitting claims.
Background
Diabetes refers to a heterogeneous group of disorders characterized by progressive loss of beta‑cell mass or function leading to hyperglycemia. A1c (glycated hemoglobin) reflects average blood glucose over the preceding 8–12 weeks and is used for screening, diagnosis, and monitoring of diabetes, while fasting plasma glucose (FPG) and oral glucose tolerance testing (OGTT) measure glucose at specific time points and remain important diagnostic alternatives, particularly in pregnancy and in conditions that affect A1c reliability.
Definitions
inv-43: A1c (HbA1c)
DefinitionGlycated hemoglobin (A1C): measure of average blood glucose over the preceding 8–12 weeks; used for screening, diagnosis, and monitoring of diabetes.
Clinical utilityProvides information about long-term glucose control and is associated with complications risk reduction when controlled
Assay methodsMeasurement methods include HPLC, boronate affinity, immunoassay, and enzymatic assays; use NGSP-certified methods for diagnosis and monitoring
inv-44: FPG (Fasting plasma glucose)
DefinitionFasting plasma glucose (FPG): plasma glucose measured after a typical overnight fast (no caloric intake ≥8 hours).
Diagnostic threshold for diabetesFPG ≥126 mg/dL establishes a diagnosis in asymptomatic individuals (requires confirmatory testing unless symptomatic).
Policy Summary
Payerblue cross blue shield - tennessee
PolicyDiabetes mellitus testing (A1c, FPG, OGTT)
Policy CodePolicy N/A
Change TypeNo material change noted
Effective DateN/A
Next Review DateN/A
Key ActionDocument clinical indication and ensure A1c is performed using an NGSP‑certified, DCCT‑standardized method; use OGTT/FPG where A1c is unreliable.
Test pregnant women at 24–28 weeks if not previously diagnosed; consider testing high-risk women before 15 weeks using FPG 110–125 mg/dL or A1C 5.9–6.4% to detect early abnormal glucose metabolism. Postpartum: test women with GDM at 4–12 weeks postpartum with a fasting 75-g OGTT using nonpregnancy criteria; if normal, retest every 1–3 years
Use and limitations of A1C: A1C testing should use NGSP-certified/DCCT-traceable methods; point-of-care A1C assays are not recommended for diagnosis and should be confirmed with laboratory measures. A1C may be unreliable in conditions affecting red blood cell turnover (eg pregnancy, hemoglobinopathies, anemia, HIV); use glucose-based tests or alternative approaches when indicated.A1C targets: pregnancy target <6% if achievable; general targets individualized
References: ADA, NACB, Diabetes Canada, AACE
Early pregnancy A1C screening range
A1C 5.9–6.4% (41–47 mmol/mol) — screen for abnormal glucose metabolism before 15 weeks gestation
Periconceptional A1C categories reportedStudies report associations across A1C strata (<6.5%, 6.5–7.8%, 7.8–9.1%, >9.1%) with increasing preterm birth risk
Use in pregnancyA1C may identify early abnormal glucose metabolism but is not sufficient alone to replace OGTT for GDM diagnosis
inv-19: Adult screening age and BMI
Screening start age (general adults)Begin testing at age 35 years for all adults (ADA recommendation)
BMI-based testing considerationConsider testing adults of any age with BMI ≥25 kg/m2 (≥23 kg/m2 in Asian Americans) plus one or more risk factors
Repeat interval if normalIf tests are normal, repeat at minimum every 3 years (sooner with symptoms or risk changes)
CPT 83037 — Hemoglobin; glycosylated (A1C) by device cleared by FDA for home use
Denial Risk
POC A1C Diagnostic Accuracy Limitation
Point‑of‑care (POC) A1c assays are not sufficiently accurate for diagnosing diabetes. If a POC A1c is used for any diagnostic consideration, the result should be confirmed with a validated laboratory method.
POC A1c assays may be NGSP certified for monitoring but have not been prospectively validated for diagnosis
Confirmatory testing with a lab-based NGSP-certified method is required for diagnostic use
Note
Government Policy Precedence
If there is any conflict between this policy and an applicable government policy (e.g., Local Coverage Determinations, National Coverage Determinations for Medicare, or state Medicaid rules), the government policy prevails and will be used to make coverage determinations.
Refer to CMS Medicare Coverage Database and applicable state Medicaid resources for current government policies
Note
No Authorization or Denial Criteria Present
This policy does not specify prior authorization or denial criteria within the Provider Actions section. Coverage determinations are tied to documented clinical indications and the criteria elsewhere in the policy.
No prior authorization requirements stated in this section
Claims should include documentation supporting the clinical indication referenced in policy
Documentation Required
Required Clinical Indication Documentation
Document the clinical indication when ordering A1c or glucose testing: the reason for testing (initial diagnosis, screening, monitoring), baseline values if applicable, intended monitoring cadence (e.g., twice yearly if stable, quarterly if not at goal), and any recent therapy changes.
Indicate whether test is for initial diagnosis, screening, or monitoring
For monitoring, document frequency: every 6 months if at goal and stable; every 3 months if not at goal or therapy changed
Include clinical context such as symptoms, pregnancy status, CF diagnosis, HIV, or other conditions affecting interpretation
Documentation Required
A1c Assay Quality and Discordance
A1c testing must be performed using an NGSP‑certified method traceable to the DCCT reference assay. Marked discordance between A1c and plasma glucose should prompt consideration of assay interference and use of alternative methods or glucose‑based criteria for diagnosis.
Use only NGSP‑certified, DCCT‑traceable A1c methods for diagnostic and monitoring purposes
If A1c is markedly discordant with plasma glucose, investigate potential assay interference (hemoglobinopathies, recent transfusion, erythropoietin) and consider alternate testing
Documentation Required
A1C Method Certification and Lab Proficiency
Laboratories performing A1c should use NGSP‑certified methods traceable to the DCCT and demonstrate traceability to IFCC where applicable. Laboratories should participate in proficiency testing (e.g., CAP HbA1c survey). Ensure testing is performed in accredited labs using validated assays.
Laboratories should participate in proficiency testing programs (eg, CAP HbA1c survey)
Use NGSP‑certified assays traceable to DCCT; manufacturers should show IFCC traceability where applicable
Point‑of‑care devices cleared for monitoring may not meet diagnostic accuracy requirements and proficiency testing may not be mandated for POC settings
Step Therapy
Step Therapy Not Specified
No step therapy or stepwise treatment requirement is specified in this policy for diabetes testing; clinical testing frequency and method are determined by indications and guideline-based recommendations.
No step therapy rules present in this policy section
Follow clinical criteria for test selection and frequency rather than step therapy rules
Documentation Required
In Pregnancy, Use of HbA1c Alone Is Insufficient
In pregnancy A1c alone is insufficiently sensitive and specific to replace OGTT for diagnosis of gestational diabetes. A1c may be used as a secondary measure or in a rule‑out strategy combined with OGTT and blood glucose monitoring, but OGTT (and glucose-based criteria) remain the preferred diagnostic test in pregnancy and postpartum.
A1c may be used as a secondary measure after blood glucose monitoring in pregnancy
OGTT is recommended at 4–12 weeks postpartum rather than A1c due to altered red blood cell turnover
Use fasting and postprandial self-monitoring of blood glucose to guide management in pregnancy
Use casesCommonly used in pregnancy (GDM screening) and cystic fibrosis-related diabetes screening; requires adequate carbohydrate intake prior to testing
inv-46: A1c diagnostic thresholds
A1C ≥6.5%Diagnostic threshold for diabetes (recommended by multiple guidelines and studies)
Prediabetes A1C rangeA1C 5.7%–6.4% (ADA/AACE); some referenced studies use 6.0%–6.5% for high-risk categories
Assay considerationsA1C should be measured with NGSP-certified, DCCT-traceable methods; discordance with glucose tests may indicate assay interference or condition affecting RBC turnover
inv-47: OGTT (75-g)
Test format75-g OGTT: oral glucose tolerance test with 75-g glucose load and 2-hour plasma glucose measurement
Diagnostic cutoff (2-hour)2-hour PG ≥200 mg/dL — diagnostic of diabetes
Postpartum useUsed postpartum after gestational diabetes to detect persistent diabetes or prediabetes (75-g OGTT at 4–12 weeks postpartum recommended)
inv-48: NGSP-certified A1C
NGSP certificationAn A1C assay method certified by the National Glycohemoglobin Standardization Program and standardized or traceable to the DCCT reference assay is required for diagnostic use.
Laboratory proficiencyLaboratories measuring A1C should participate in proficiency testing programs (eg, CAP HbA1c survey) and document assay certification and proficiency participation.
POC limitationsPoint-of-care A1C assays are not recommended alone for diagnosis and, if used, require confirmation with a validated laboratory method.
inv-52: HbA1c standardization
Standardization referencesIFCC/NGSP reference measurement systems and standardization reports underpin A1C measurement accuracy and traceability.
Key guidancesInternational Expert Committee, IFCC, and NACB publications cited for A1C standardization and laboratory best practices.
PurposeStandardization ensures comparability of A1C results across laboratories and supports diagnostic use when NGSP-certified methods are employed.
inv-51: Gestational diabetes mellitus (GDM)
GDM definitionGestational diabetes mellitus (GDM): carbohydrate intolerance first recognized during pregnancy; universal screening at 24–28 weeks' gestation recommended.
One-step approach (75-g)75-g 2-hour OGTT diagnostic cutoffs: FPG ≥92 mg/dL, 1-hour ≥180 mg/dL, 2-hour ≥153 mg/dL (one abnormal value sufficient for diagnosis per some criteria).