Diabetes Mellitus diagnostic and monitoring laboratory testing (A1c, FPG, OGTT)
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Defines medical coverage and reimbursement criteria for laboratory testing used to diagnose, screen for, and monitor diabetes mellitus and prediabetes for Blue Cross Blue Shield - North Carolina members.
Policy renamed and expanded to address additional testing beyond Hemoglobin A1c to align with Avalon.
Reimbursement is allowed for screening for prediabetes or type 2 diabetes once every three years with a fasting plasma glucose test for asymptomatic individuals who are 35 years of age or older and who have no risk factors for diabetes.
Updated When Covered section to add quarterly hemoglobin A1c testing for individuals who are pregnant.
Added coverage for individuals with metabolic dysfunction-associated steatotic liver disease (MASLD).
Edits to notes clarifying when hemoglobin A1c is not allowed and removal of certain exclusions for pediatric age in Note 3.
Billing/Coding section updated to add CPT code 82947.
Coverage Criteria and Clinical Indications
Covered Indications and Monitoring Frequency
Covered when ANY of the following conditions are met (or as specified):
ADA-based coverage criteria for diabetes testing
Covered when meeting ADA-recommended testing indications and using appropriate validated assays
Guideline-derived screening and diagnostic criteria
Recommendations summarized (by source) for screening, diagnosis, and monitoring:
Monitoring and special populations
Guideline-based screening and diagnostic criteria
Coverage and testing are aligned to guideline-based diagnostic thresholds and recommended screening populations:
Gestational diabetes screening and diagnosis
Pregnancy-specific screening and diagnostic criteria per AACE:
Selected When Covered items (partial)
When Covered highlights and recent additions
Added 2/21/24
Added/Updated 2/26/25
Added 2/26/25
Measurement of hemoglobin A1c is not covered except where expressly allowed in this policy. Per the policy notes, A1c should not be performed in any of the following situations: to test for diabetes in individuals presenting with acute or persistent classic symptoms of diabetes; in pregnant individuals without an established diagnosis of diabetes or prediabetes; to screen for diabetes in individuals with cystic fibrosis; in conjunction with measurement of fructosamine; or in individuals with conditions associated with increased red blood cell turnover (for example, sickle cell disease, recent transfusion, erythropoietin therapy, hemodialysis, or certain HIV-related conditions).
Fasting plasma glucose testing is not covered when performed at a routine wellness visit with no abnormal findings unless another policy provision specifically authorizes it. The policy explicitly states that reimbursement is not allowed for FPG at a wellness visit with no abnormal findings for situations not otherwise addressed, and this denial trigger was reiterated in the policy updates.
The policy states that A1c is not recommended as a screening test for cystic fibrosis–related diabetes (CFRD) because studies demonstrate low sensitivity and poor diagnostic accuracy compared with the 2‑hour OGTT. Evidence cited shows weak correlations between A1c and OGTT results and low ROC‑AUC values for A1c in CF populations, and the ADA recommends annual OGTT beginning by age 10 for CF patients rather than relying on A1c alone.
The policy specifies that A1c should not be used alone to diagnose diabetes in certain populations. Examples include children with cystic fibrosis, individuals with suspected type 1 diabetes, and persons with hemoglobinopathies or other conditions that interfere with A1c measurement; guidance from the ADA and Diabetes Canada caution against relying solely on A1c in these situations and recommend using plasma glucose criteria or additional testing (e.g., OGTT, pancreatic autoantibodies) as appropriate.
The policy clarifies that A1c should not be used for gestational diabetes (GDM) screening or diagnosis because physiological changes during pregnancy affect glycated hemoglobin and reduce its reliability. AACE and ADA guidance in the policy endorse OGTT‑based approaches for universal screening at 24–28 weeks and state that A1c is not appropriate for routine GDM diagnosis.
Consistent with the policy’s exclusions and recent updates, reimbursement is not allowed for fasting plasma glucose testing performed at a wellness visit with no abnormal findings except where a specific When Covered rule authorizes screening (for example, the once‑every‑3‑years allowance for asymptomatic individuals ≥35 without risk factors). The policy restates this denial trigger and notes it was added to clarify coverage scope.
Use of A1c in the situations enumerated as inappropriate in the policy (for example, symptomatic diagnostic testing, screening in pregnancy without an established diagnosis, screening for CFRD, concurrent fructosamine testing, or testing in individuals with conditions causing altered red blood cell turnover) is considered not covered or not medically necessary. Providers should follow the policy notes and coverage exceptions when ordering tests to ensure reimbursement.
The policy indicates that A1c alone should not replace the OGTT for diagnosing gestational diabetes or cystic fibrosis–related diabetes. Clinical studies summarized in the policy show that A1c lacks sufficient sensitivity and specificity in pregnancy and CF populations and therefore is not supported as the sole diagnostic test to substitute for OGTT in these contexts.
The policy cites the USPSTF position that evidence is insufficient (I statement) to assess the benefits and harms of screening for type 2 diabetes in asymptomatic children and adolescents younger than 18 years. This uncertainty underpins the policy’s caution about routine universal screening in asymptomatic youth and supports the policy’s age‑ and risk‑based screening approach.
Except where specifically described as covered in the policy, reimbursement is not allowed for measurement of hemoglobin A1c. The policy’s When Not Covered language and associated notes were updated to clarify situations in which A1c testing is not allowable; providers should consult Note 2/Note 3 in the policy when documentation is requested for medical necessity determinations.
Policy notes were added and edited to clarify circumstances when hemoglobin A1c measurements are not allowed; providers must follow these notes and document the clinical indication that meets the policy’s covered criteria. The policy also reminds providers to confirm member benefit design, to document test methods (for example, use of NGSP‑traceable A1c assays or FDA‑approved POC devices in CLIA‑certified settings), and to supply requested records when BCBSNC requests medical documentation to support reimbursement.
Billing, Codes, and Diagnostic Thresholds
| 82947 | Glucose; quantitative, blood (except reagent strip) |
| 82951 | Glucose; tolerance test (GTT), 3 specimens (includes glucose) |
| 82952 | Glucose; tolerance test (GTT), 4 specimens (includes glucose) |
| 82985 | Glucose, post partum glucose screening |
| 83036 | Hemoglobin; glycosylated (A1C) |
| 83037 | Hemoglobin; glycosylated (A1C), automated, per form |
Provider Requirements, Documentation, and Billing Guidance
No procedural prior authorization codes specified
This policy segment does not specify any procedural prior authorization requirements for diabetes testing; providers should follow the coverage criteria and check administrative prior-authorization policies if applicable.
- Policy text: “The policy states coverage and reimbursement criteria but does not specify procedural prior authorization codes in this portion of the document.”
Prior authorization not required per this excerpt — verify plan rules
No explicit prior authorization requirement is stated in the policy for ordering A1C, FPG, or OGTT; order tests in accordance with the ADA/When Covered criteria in the policy and verify any plan-specific authorization rules separately.
- Follow ADA screening indications (age/risk-based) and the policy's When Covered rules when deciding to test.
No explicit prior authorization requirement in guideline excerpts
The document includes no separate prior authorization statements for diabetes testing; clinical indications and coverage frequency rules in the When Covered section govern allowable testing.
- When Covered section lists covered testing circumstances and frequencies (e.g., A1C frequencies, FPG screening intervals).
Applicable service codes listed — reimbursement not guaranteed
List of CPT codes is provided for tests in the Billing/Coding section, but inclusion in the policy does not guarantee reimbursement; consult BCBSNC administrative policies and confirm benefit design before submitting claims.
No step therapy required for testing pathways
No step therapy or sequencing requirements are specified for diabetes testing in this policy excerpt; clinicians should order the test most appropriate for the clinical scenario per guideline and policy criteria.
- Policy/clinical guidance notes limitations of A1C in certain populations (e.g., CF) where OGTT is preferred; no step therapy language is present.
Confirm member benefits and meet medical criteria for reimbursement
Confirm member benefit design before applying the policy; reimbursement for testing is contingent on meeting the medical criteria in the When Covered section and on benefit availability.
- “Member benefit language should be reviewed before applying the terms of this medical policy.”
- Testing reimbursement contingent on meeting medical criteria in the When Covered section.
Document A1C method and any discordant/confirmatory testing
Document test methodology and any discordant or confirmatory results in the medical record: use NGSP-certified/traceable A1C methods and, when applicable, FDA‑approved POC A1C devices in CLIA‑certified laboratories; if A1C and glucose results are markedly discordant, document repeat/confirmatory testing and interpretation.
- “The A1C test should be performed using a method that is certified by the National Glycohemoglobin Standardization Program (NGSP) as traceable to the DCCT reference assay.”
- “Point-of-care A1C testing for diabetes screening and diagnosis should be restricted to U.S. Food and Drug Administration–approved devices at CLIA‑certified laboratories…”
- “Marked discordance between A1C and repeat blood glucose values should raise the possibility of a problem or interference with either test.”
Document A1C within prior 3 months for hospitalized patients
For hospitalized patients with diabetes or hyperglycemia (random glucose >140 mg/dL), document an A1C result within the prior 3 months or perform and record an A1C during admission if no result is available from the prior 3 months.
- “Perform an A1C test on all people with diabetes or hyperglycemia (random blood glucose >140 mg/dL) admitted to the hospital if no A1C test result is available from the prior 3 months.”
- When Covered allows A1C for individuals with diagnosed diabetes per specified frequencies.
Provide full medical records when requested — letters alone insufficient
When BCBSNC requests medical records to determine medical necessity, include all required clinical information (test results, methods, dates, and supporting documentation); letters alone are insufficient and failure to provide records may lead to claim denial or nonpayment.
- “BCBSNC may request medical records for determination of medical necessity. When medical records are requested, letters of support and/or explanation are often useful but are not sufficient documentation unless all specific information needed to make a medical necessity determination is included.”
- Absence of requested documentation may lead to claim denial or nonpayment.
Document adherence to policy notes on when A1C is not allowed
Follow the policy notes that clarify when hemoglobin A1C measurements are not allowed; document indications that meet the policy's When Covered criteria to support medical necessity.
- Note 2 lists situations where A1C should not be performed (e.g., symptomatic diagnostic testing, pregnancy without established diagnosis, CF screening, conjunctive fructosamine testing, conditions with increased RBC turnover).
- When Covered lists allowable indications and frequencies (e.g., quarterly in pregnancy, screening intervals).
Denial risk: testing performed in not-covered situations
Do not bill or expect reimbursement for A1C or FPG in situations the policy designates as not covered (e.g., A1C for situations not described in the policy; FPG at a wellness visit with no abnormal findings).
- “Reimbursement is not allowed for measurement of hemoglobin A1c for all other situations not previously described.”
- “Reimbursement is not allowed for fasting plasma glucose testing at a wellness visit with no abnormal findings for all other situations not addressed above.”
Laboratory method and device requirements for A1C testing
Use NGSP‑certified A1C methods for diagnostic use and restrict point‑of‑care A1C testing for screening/diagnosis to FDA‑approved devices in CLIA‑certified laboratories; failure to meet these laboratory/device standards risks inaccurate results and potential denial.
- “The A1C test should be performed using a method that is certified by the National Glycohemoglobin Standardization Program (NGSP)…”
- “Point‑of‑care A1C testing for diabetes screening and diagnosis should be restricted to U.S. FDA‑approved devices at CLIA‑certified laboratories…”
Failure to obtain A1C for hospitalized patients risks care standard noncompliance
If a hospitalized patient with diabetes or a random blood glucose >140 mg/dL does not have an A1C result from the prior 3 months and an A1C is not performed, this may conflict with ADA inpatient care standards and could affect clinical care decisions.
- “Perform an A1C test on all people with diabetes or hyperglycemia (random blood glucose >140 mg/dL) admitted to the hospital if no A1C test result is available from the prior 3 months.”
Medical record requests may affect reimbursement — provide documentation
BCBSNC may request supporting medical records to substantiate medical necessity; failure to provide the requested documentation can result in claim denial or nonpayment.
- “BCBSNC may request medical records for determination of medical necessity.”
- Inclusion of a code in Billing/Coding does not guarantee reimbursement; records may be required to support claims.
Denial trigger: routine wellness FPG with no abnormal findings
Do not expect reimbursement for fasting plasma glucose testing performed at a wellness visit with no abnormal findings unless another covered indication applies; the policy explicitly excludes that scenario.
- “Reimbursement is not allowed for fasting plasma glucose testing at a wellness visit with no abnormal findings for all other situations not addressed above.”
Clinical Background and Rationale
Diabetes mellitus encompasses heterogeneous disorders characterized by progressive loss of β‑cell mass or function and resultant hyperglycemia. Hemoglobin A1c reflects average glycemia over approximately 8–12 weeks and is a standard tool for diagnosis and monitoring when performed using NGSP‑certified methods; however, plasma glucose‑based tests (FPG and OGTT) remain preferred in situations where A1c is unreliable (for example, pregnancy, certain hemoglobinopathies, recent transfusion, or conditions with altered red blood cell turnover).
Definitions and Diagnostic Thresholds
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