Hemoglobin A1c (Diabetes Mellitus testing)
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Defines coverage and reimbursement criteria for plasma glucose, OGTT, and hemoglobin A1c testing for diagnosis, screening, and monitoring of diabetes, prediabetes, gestational diabetes, cystic fibrosis–related diabetes, and testing related to antiretroviral therapy; applies to Blue Cross Blue Shield North Carolina providers and members.
Updated When Covered section to allow quarterly testing for individuals who are pregnant and added coverage for individuals with metabolic dysfunction-associated steatotic liver disease (MASLD).
Policy renamed and expanded from Hemoglobin A1c to Diabetes Mellitus Testing to align with Avalon; fasting plasma glucose testing was added and coverage criteria expanded.
Added reimbursement allowance once per month during pregnancy for measurement of hemoglobin A1c (historical change noted 12/10/19).
Added statement allowing screening for prediabetes or type 2 diabetes once every three years with fasting plasma glucose for asymptomatic individuals 35+ without risk factors.
Coverage Criteria for Diabetes Mellitus Testing
Covered indications (screening, diagnosis, monitoring)
Covered when ANY of the following situations apply (policy lists discrete covered indications):
Source: When measurement of Diabetes Mellitus testing is covered; plasma glucose reimbursement allowed for symptomatic individuals.
Detailed frequency options listed in policy 'When measurement of Diabetes Mellitus testing is covered' (see #2 and subitems).
Policy allows annual screening for prediabetes/type 2 diabetes for prediabetic individuals.
Policy specifies FPG every 3 years for asymptomatic ≥35 with no risk factors.
Policy lists specific risk factors qualifying for triennial screening (When covered #5 and subitems).
Policy aligns with ADA recommendations for people with HIV (When covered #6 and #6 subitems; ADA guidance).
Policy allows annual OGTT for CF patients (When covered #7).
Policy details pediatric risk-based screening and triennial interval (When covered #8).
When covered #9 states monthly FPG or OGTT during pregnancy; A1c frequency for pregnancy addressed elsewhere in policy history and updates.
When covered #10 and subitems specify OGTT timing and repeat testing for GDM postpartum.
Guideline-based Coverage/Monitoring Criteria
Guideline-based testing and monitoring recommendations (not insurer-authorization rules):
References: ADA, USPSTF/AACE/Diabetes Canada guidance summarized in policy (chunks 36,37,53).
Based on AACE/WHO/Diabetes Canada and ADA statements (chunks 36,53).
AACE/Diabetes Canada/ADA recommendations cited (chunks 36,37,53).
ADA and NICE frequency recommendations (chunks 36,38,53).
ADA HIV guidance and pregnancy cautions; NICE and Diabetes Canada comments (chunks 36,38,53).
ADA hospital and perioperative guidance summarized in policy (chunks 43,53).
Covered Indications and Frequency
Covered when policy-specific medical necessity and guideline-derived criteria are met (policy expansions noted below).
Policy history: 12/10/19 monthly allowance; 2/26/25 updated When Covered to add quarterly A1c in pregnancy (chunks 75,77).
Policy implementation note 2/21/24 added this triennial FPG allowance (chunk 76).
Policy update 2/26/25 added MASLD to When Covered risk factors (chunk 77).
Measurement of hemoglobin A1c is not covered when used for situations not specifically listed in the policy’s covered indications. The policy explicitly states that A1c testing is not allowed, for example, to evaluate individuals presenting with acute or persistent classic symptoms of diabetes, in pregnant individuals without a prior diagnosis of diabetes or prediabetes, to screen individuals with cystic fibrosis, in conjunction with fructosamine, or in any circumstance associated with increased red blood cell turnover (e.g., sickle cell disease, recent transfusion, erythropoietin therapy, hemodialysis, or HIV).
Reimbursement is also not allowed for fasting plasma glucose testing performed at a routine wellness visit with no abnormal findings when that situation is not addressed in the When Covered section of the policy.
Certain conditions alter the relationship between A1c and average glycemia and should prompt use of plasma glucose–based testing instead. The ADA notes that hemoglobin variants, pregnancy in the second and third trimesters and the postpartum period, glucose‑6‑phosphate dehydrogenase deficiency, HIV, hemodialysis, recent blood loss or transfusion, and erythropoietin therapy are situations in which plasma glucose criteria should be used to diagnose diabetes.
The policy reinforces these guideline cautions and lists pregnancy (second/third trimester and postpartum) and hemoglobin variants among the conditions in which A1c may be unreliable and alternative testing is preferred.
When conditions that affect erythrocyte lifespan or hemoglobin structure are present, A1c should not be used as the sole diagnostic test. NICE and ADA guidance recommend using quality‑controlled plasma glucose profiles, fasting plasma glucose, or OGTT in these settings and advise investigation of unexplained discrepancies between A1c and glucose measurements.
Providers must rely on plasma glucose criteria to establish a diagnosis when there is potential interference from hemoglobinopathies, altered red blood cell turnover, or other factors noted in guidance.
A1c is not recommended for screening or diagnosis of gestational diabetes. AACE and ADA state that physiological changes in pregnancy alter glycated hemoglobin levels; therefore screening for gestational diabetes should use glucose‑based testing (universal screening at 24–28 weeks with FPG and/or OGTT as described by guidelines).
Guidance also emphasizes that A1c may be misleading in pregnancy and glucose‑based tests remain the standard for gestational diabetes screening and diagnosis.
The policy specifies that reimbursement is not allowed for fasting plasma glucose testing performed at a wellness visit when there are no abnormal findings and the situation is not covered by the When Covered criteria. This denial trigger was added as part of the 2/21/24 policy update and is intended to limit payment for routine FPG testing at a wellness visit unless a covered indication or abnormal finding is documented.
Providers should document an applicable covered indication or abnormal clinical finding when ordering FPG at a wellness visit to support medical necessity and reimbursement.
Hemoglobin A1c measurement is considered not medically necessary when it is used outside the policy’s listed covered indications. The policy explicitly lists scenarios where A1c should not be performed (see Note 2) and states that reimbursement is not allowed for A1c testing for any other situations not described in the When Covered section.
In practice, providers must follow the When Covered criteria to establish medical necessity; inclusion of service codes in the billing section does not guarantee reimbursement if the clinical indication is not met and BCBSNC may request medical records to determine necessity.
A1c has limited diagnostic accuracy for cystic fibrosis–related diabetes (CFRD) and pre‑CFRD dysglycemia. Studies cited in the policy report low ROC‑AUC values for A1c and other alternate markers when compared to the OGTT gold standard—ROC‑AUCs ranged from about <0.6 for CFRD and 0.52–0.67 for pre‑CFRD states, with poor sensitivity and specificity in small CF cohorts.
Because of these limitations the policy (and ADA guidance) recommend annual OGTT screening beginning by age ten for people with cystic fibrosis and state that A1c is not recommended as a screening test for CFRD, although an A1c ≥6.5% is consistent with CFRD if present.
The USPSTF concluded that current evidence is insufficient to assess the balance of benefits and harms of screening for type 2 diabetes in asymptomatic children and adolescents younger than 18 years and assigned an “I” statement for this population.
As a result, routine population screening of asymptomatic youth <18 years is not recommended by USPSTF pending clearer evidence linking screening to improved health outcomes.
Reimbursement exclusions for hemoglobin A1c and fasting plasma glucose are reinforced in the policy’s When Not Covered section. The policy reiterates that A1c testing is not payable for situations outside the enumerated covered indications and that FPG performed at a wellness visit with no abnormal findings is not reimbursed unless addressed by the When Covered criteria.
Providers should confirm that the test indication matches the policy’s covered scenarios before billing; BCBSNC may request clinical documentation to adjudicate claims.
Billing and Diagnostic Thresholds
Provider Actions, Documentation, and Billing Guidance
Follow policy When Covered criteria when billing; no separate PA listed
This policy defines coverage criteria and reimbursement guidelines for plasma glucose, OGTT, and hemoglobin A1c testing; providers must follow the When Covered criteria in the policy when submitting claims for diabetes testing. The policy does not list separate prior authorization requirements in the cited sections.
- Follow the policy's When Covered criteria (e.g., baseline A1c at diagnosis; quarterly or every 6 months per control; screening intervals listed in When Covered).
- No explicit prior authorization rules are stated in the referenced guideline extracts — bill according to coverage criteria and group contract benefits.
Laboratory method and device requirements for A1C (NGSP-certified; POC FDA/CLIA limits)
A1C testing used for diagnosis or monitoring must be performed using NGSP-certified methods traceable to the DCCT reference assay; point-of-care A1C testing is limited to FDA-approved devices in CLIA-certified settings with appropriate personnel and proficiency testing.
- Use NGSP-certified, DCCT-traceable assay methods for A1C (ADA requirement).
- POC A1C: only FDA-cleared devices may be used in CLIA-certified labs/sites with documented annual competency and participation in proficiency testing (per ADA).
- If conditions alter A1C accuracy (hemoglobin variants, pregnancy 2nd/3rd trimester/postpartum, G6PD deficiency, HIV, hemodialysis, recent transfusion/bleeding, erythropoietin therapy), use plasma glucose criteria or alternate testing.
No explicit prior authorization requirement in cited sections
The document excerpts do not specify any separate prior authorization program or codes that require PA; providers should follow coverage criteria and submit claims per contract terms.
- No explicit prior authorization requirements are stated in these guideline extracts.
Bill listed service codes; records may be requested to confirm medical necessity
Bill using the service codes listed in the policy, but inclusion of a code does not guarantee reimbursement; BCBSNC may request medical records to determine medical necessity.
No step therapy requirements for testing
No step therapy or step-wise treatment prerequisite is described in the policy excerpts for A1C, FPG, or OGTT testing.
- Screening strategy references note that OGTT, FPG, and A1C are appropriate tests and OGTT is required for annual CFRD screening beginning at age 10; this is not a step therapy requirement.
Screening tests: OGTT, FPG, and A1C — OGTT required annually for CFRD
OGTT, FPG, and A1C are appropriate diagnostic/screening tests per guidelines; annual OGTT is required for cystic fibrosis–related diabetes (CFRD) screening beginning at age 10, and FPG/A1C can be used for routine screening per policy criteria.
- Use OGTT annually for CFRD screening in individuals ≥10 years with cystic fibrosis (ADA/Diabetes Canada guidance cited).
- Use FPG or A1C for screening and diagnosis per the policy's When Covered criteria and guideline recommendations.
Reinforcement: No step therapy described
No additional step therapy requirements are described in the referenced sections.
- Reinforces that no step therapy applies to these testing indications.
Policy source fallback (full document reference)
Full source available for reference; see policy document for complete coverage criteria, exclusions, and coding details.
- Refer to the full Diabetes Mellitus Testing (AHS G2006) policy for comprehensive details, as this block is a placeholder to access the source.
Policy source fallback (alternate)
Full source available for reference; see policy document for comprehensive guidance on coverage and documentation.
- This placeholder callout points to the full policy for any details not captured elsewhere.
Document diagnosis and clinical indication; note expected monitoring frequency
Document the member's diabetes diagnosis and the clinical indication for A1C testing (baseline at diagnosis, monitoring frequency: every 6 months if stable, quarterly if not meeting goals or after therapy change, and during pregnancy).
- Record type 1 or type 2 diabetes diagnosis and specific reason for A1C (e.g., baseline, monitoring, after medication change, pregnancy).
- Follow guideline-based monitoring intervals: every 3 months if therapy/control changing; every 6 months when stable.
A1C must be performed using NGSP-certified, DCCT-traceable methods; POC limits
A1C must be measured using NGSP-certified methods traceable to the DCCT reference assay; point-of-care testing is limited to FDA-cleared devices used in CLIA-certified laboratories with trained personnel and required proficiency testing.
- Use NGSP-certified/ DCCT-traceable assays for diagnostic or monitoring A1C testing.
- POC A1C testing: only FDA-approved devices in CLIA-certified settings with documented personnel competency and participation in approved proficiency testing programs.
Hospital and perioperative A1C documentation requirements
For hospitalized or perioperative patients, document a recent A1C (within prior 3 months) for admitted patients with diabetes or random blood glucose >140 mg/dL; for elective surgery document A1C goal when scheduling (goal <8% when possible) and perioperative glucose targets.
- Perform and document A1C if no result in prior 3 months for hospitalized patients with diabetes or random BG >140 mg/dL.
- For elective surgery, document A1C goal (<8% if possible) and perioperative glucose target (100–180 mg/dL within 4 hours of surgery).
Medical records may be requested; letters alone often insufficient
BCBSNC may request medical records to determine medical necessity; when records are requested, letters alone are not sufficient unless they contain all information needed for the determination.
- Maintain complete medical records documenting diagnosis, indication, and test justification.
- Include all supporting clinical information when submitting records; letters without full documentation may be insufficient.
Use When Covered criteria to determine medical necessity and check member benefits
Follow the policy's When Covered criteria to determine medical necessity for hemoglobin A1c and fasting plasma glucose testing; benefits and eligibility are determined by the group contract and subscriber certificate.
- Verify member eligibility and benefits prior to testing; coverage requires meeting the documented When Covered criteria.
- Policy changes (renaming/expansion, screening intervals) are recorded in policy history—ensure using the current version.
Situations triggering noncoverage for A1C
A1C testing is not reimbursed when performed for situations outside the policy's covered indications (see When Not Covered); specifically, do not bill A1C for testing individuals presenting with acute classic symptoms, pregnant individuals without established diagnosis, screening for CF, in conjunction with fructosamine, or in conditions with increased RBC turnover.
- Do not submit claims for A1C when used to test symptomatic individuals with acute/persistent classic diabetes symptoms.
- Do not submit A1C for pregnancy screening if no established diagnosis of diabetes/prediabetes, for CF screening, or when RBC turnover conditions exist (e.g., sickle cell disease, recent transfusion, erythropoietin therapy).
Marked discordance between A1C and glucose — investigate and use plasma glucose criteria
If there is marked discordance between an A1C result and repeat blood glucose values, consider possible assay interference or error and use plasma glucose criteria to diagnose diabetes rather than relying on the A1C.
- Investigate unexplained discrepancies between A1C and other glucose measurements and consider specialist advice (diabetes or clinical biochemistry) as needed.
- In these situations, rely on plasma glucose criteria (FPG or OGTT) for diagnosis.
Risk of noncoverage for hospitalized patients without recent A1C documentation
Failure to document an A1C within the prior 3 months for hospitalized patients with diabetes or random blood glucose >140 mg/dL may result in noncompliance with care standards and potential noncoverage concerns.
- Ensure admission records include an A1C within 3 months or perform testing on admission and document results to support medical necessity.
- Lack of documentation may trigger requests for records or coverage denial for hospital-related claims tied to glucose management.
Documentation and reimbursement risk: code inclusion ≠ guaranteed payment
Inclusion of a billing code in the policy does not guarantee reimbursement; BCBSNC may request medical records to determine medical necessity and coverage under the member's contract.
Denial trigger: FPG at wellness visit without abnormal findings
Reimbursement is not allowed for fasting plasma glucose testing performed at a wellness visit with no abnormal findings or other covered indications as described in the policy.
- Do not bill for FPG at routine wellness visits absent abnormal findings or a covered indication described in the When Covered section.
- Verify clinical indication before ordering FPG to avoid denial.
Background and Rationale
Diabetes represents a heterogeneous group of disorders resulting in hyperglycemia due to β‑cell dysfunction and/or insulin resistance. Hemoglobin A1c reflects average glycemic exposure over approximately the preceding 8–12 weeks and is used for diagnosis, screening, and monitoring of diabetes and prediabetes in many populations.
However, A1c measures glycated hemoglobin rather than direct plasma glucose and can be affected by conditions that change erythrocyte lifespan or hemoglobin structure; for these reasons guideline bodies emphasize use of NGSP‑certified, DCCT‑traceable A1c assays for diagnosis and recommend glucose‑based testing (FPG or OGTT) when A1c may be unreliable.
Definitions and Reference Thresholds
Policy Revision History
New Hemoglobin A1c policy developed; noticed 4/1/2019 for effective date 2019-06-01 with Medical Director review on 4/1/2019.
Coding section updated and When Covered section #5 added reimbursement allowance once per month during pregnancy for measurement of hemoglobin A1c.
Policy renamed and expanded from Hemoglobin A1c to Diabetes Mellitus Testing, fasting plasma glucose testing added, When Covered expanded, and billing codes 82951 and 82952 added.
Added allowance for screening with fasting plasma glucose once every three years for asymptomatic individuals age ≥35 with no risk factors and clarified When Not Covered language.
When Covered updated to allow quarterly A1c testing for individuals who are pregnant and to add coverage for individuals with metabolic dysfunction-associated steatotic liver disease (MASLD); notification given 2/26/2025 for effective date 2025-04-30.
Billing/Coding section updated to add code 82947 (no change to policy clinical statement).
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