CurrentCapital BluecrossPolicy AHS - G2006 - Diabetes Mellitus Testing

Diabetes Mellitus Testing

Defines coverage criteria and clinical indications/limitations for diabetes testing modalities (plasma glucose, OGTT, hemoglobin A1c) including diagnostic, monitoring, screening (including cystic fibrosis-related and gestational diabetes) per Capital BlueCross policy AHS - G2006. Includes background, guideline alignment, and terminology.

Policy Summary

PayerCapital Bluecross

PolicyDiabetes Mellitus Testing

Policy CodePolicy AHS - G2006 - Diabetes Mellitus Testing

Change TypeRevision (no material change indicated)

Effective Date

Next Review Date

Key ActionDocument diagnosis, symptoms, and the specific clinical trigger when ordering plasma glucose, A1c, or OGTT testing as described in provider actions.

SourceLink

POLICY UPDATE CHANGES

Revision Date: 03/01/2026 recorded in header.

3Primary covered testing categories (plasma glucose / A1c / OGTT)

10+Terminology entries listed

2024Latest guideline year referenced (ADA)

HighContent Complexity

Coverage Summary

Defines coverage criteria and clinical indications/limitations for diabetes testing modalities (plasma glucose, OGTT, hemoglobin A1c) including diagnostic, monitoring, and screening use cases (including cystic fibrosis-related and gestational diabetes) per Capital BlueCross policy AHS - G2006. Coverage stance: covered_with_criteria.

Policy metadata and covered testing categories

policy_numberAHS - G2006 - Diabetes Mellitus Testing

subjectDiabetes Mellitus Testing

statusCURRENT

last_review2026-03-01

primary_covered_testing_categoriesPlasma glucose (FPG/OGTT); Hemoglobin A1c (A1c); Oral glucose tolerance testing (OGTT)

Medical-Necessity Criteria

General Coverage Criteria

Coverage applies when ALL of the following conditions per listed sections and situations are met:

Plasma glucose testing for symptomatic individuals: For individuals with acute or persistent classic symptoms of diabetes mellitus, measurement of plasma glucose MEETS COVERAGE CRITERIA.

Document symptoms (eg, polyuria, polydipsia, nocturia, blurred vision, unexplained weight loss).

Hemoglobin A1c testing for individuals with diagnosed diabetes

One of these situations: Upon initial diagnosis to establish a baseline value and to determine treatment goals.
One of these situations: Quarterly in individuals who are meeting treatment goals and who, based on daily glucose monitoring, appear to have stable glycemic control.

Diagnostic Thresholds & Monitoring Targets

Diagnostic, screening and target thresholds

FPG (diagnostic)>= 126 mg/dL

2-hour PG (75-g OGTT, diagnostic)>= 200 mg/dL

A1c (diagnostic)>= 6.5%

A1c (prediabetes)5.7% to <6.5% (or 5.7%-6.4% per some sources)

Impaired fasting glucose (IFG)FPG 100-125 mg/dL

Impaired glucose tolerance (IGT)2-h PG 140-199 mg/dL

Random PG with symptoms (diagnostic)>= 200 mg/dL with classic hyperglycemia symptoms

Coding

Applicable CPT/HCPCS Procedure Codes referencedCPT|HCPCS

82985	Glycated protein
83037	Hemoglobin; glycosylated (A1C) by device cleared by FDA for home use

Applicable CPT/HCPCS Procedure Codes (section header present; specific codes not provided in Part 1)mixed

No codes listed

Provider Actions & Requirements

Documentation Required

Document symptoms for plasma glucose testing

Document clinical indication or classic symptoms (e.g., polyuria, polydipsia, nocturia, unexplained weight loss, blurred vision) when ordering plasma glucose testing to establish medical necessity.

Affected codes: plasma glucose diagnostic measurements (see applicable code table).

Documentation Required

Document diagnosis for A1c testing

Record the specific diabetes-related diagnosis or clinical rationale when ordering hemoglobin A1c testing (initial diagnosis, baseline measurement, treatment monitoring, therapy change, pregnancy-related monitoring, or quarterly surveillance) to support coverage.

Use diagnosis codes that reflect type 1 or type 2 diabetes, gestational diabetes, or prediabetes as applicable.

Background & Evidence

Diabetes comprises heterogeneous disorders characterized by hyperglycemia from loss of β-cell mass and/or function; classification includes type 1, type 2, gestational diabetes, monogenic forms, and diabetes secondary to exocrine pancreatic disease such as cystic fibrosis. Fasting plasma glucose (FPG), two-hour plasma glucose during a 75-g oral glucose tolerance test (OGTT), and hemoglobin A1c (A1c) are established diagnostic tools; in asymptomatic individuals, FPG ≥126 mg/dL or 2‑hour PG ≥200 mg/dL (75 g OGTT) or A1c ≥6.5% meet diagnostic criteria, while prediabetes ranges include FPG 100–125 mg/dL, 2‑hour PG 140–199 mg/dL, and A1c 5.7%–6.4%/5.7% to <6.5%.

Analytical validity differs between assays: A1c measurement is well-standardized (IFCC/NGSP/DCCT traceability) with lower short-term biological variability and greater analytical stability than plasma glucose, but A1c can be unreliable in conditions altering red blood cell turnover or hemoglobin (e.g., certain hemoglobinopathies, pregnancy, advanced CKD, HIV, recent transfusion). In these settings, plasma glucose criteria or alternative biomarkers (fructosamine, glycated albumin) are preferred or considered. Point-of-care A1c devices must be NGSP/ FDA-cleared and used in CLIA-certified settings with proficiency testing.

Special populations and use cases: annual OGTT screening for cystic fibrosis patients beginning at age ten is recommended because A1c has poor sensitivity for CFRD; gestational diabetes screening follows one-step (75-g OGTT with cutoffs FPG ≥92 mg/dL, 1‑h ≥180 mg/dL, 2‑h ≥153 mg/dL) or two-step approaches (50‑g GCT screening then 100‑g 3‑h OGTT with defined thresholds), with early pregnancy screening and postpartum 75‑g OGTT at 4–12 weeks to detect persistent diabetes. Guideline alignment: recommendations are summarized from major bodies including the ADA Standards of Care (2024), AACE/AACE-ACE, USPSTF, KDIGO and others.

Evidence highlights and guideline citations

Definitions / Terminology

term	definition
A1c
Glycated hemoglobin; measure of glycemic control over prior 8-12 weeks
FPG
Fasting plasma glucose
OGTT
Oral glucose tolerance test
CFRD
Cystic fibrosis-related diabetes
GDM
Gestational diabetes mellitus
FIB-4
Fibrosis-4 index (age, ALT, AST, platelets) used to estimate liver fibrosis risk
ELF
Enhanced liver fibrosis blood biomarker

Revision History

03/01/2026revisionLatest

Revision Date: 03/01/2026 recorded in header; no material policy change identified in this part.

Policy Summary

PayerCapital Bluecross

PolicyDiabetes Mellitus Testing

Policy CodePolicy AHS - G2006 - Diabetes Mellitus Testing

Change TypeRevision (no material change indicated)

Effective Date

Next Review Date

Key ActionDocument diagnosis, symptoms, and the specific clinical trigger when ordering plasma glucose, A1c, or OGTT testing as described in provider actions.

SourceLink

On This Page

One of these situations: Quarterly in individuals who are not meeting treatment goals for glycemic control.

One of these situations: Quarterly in individuals whose pharmacologic therapy has changed.

One of these situations: Quarterly for individuals who are pregnant.

OGTT for cystic fibrosis: For individuals 10 years of age and older who have been diagnosed with cystic fibrosis but not with CF-related diabetes, annual screening for CF-related diabetes with an OGTT MEETS COVERAGE CRITERIA.

Begin annual OGTT by age 10; A1c not recommended as screening for CFRD due to low sensitivity.

Diagnostic thresholds and use cases (documented guidance)

Diagnostic criteria described in policy scientific background and ADA guidance:

Diagnostic thresholds and use cases: In an asymptomatic individual, FPG ≥ 126 mg/dL establishes a diagnosis of diabetes. Two-hour plasma glucose values of ≥200 mg/dL during a 75 g OGTT establish a diagnosis of diabetes. A1c ≥ 6.5% is diagnostic of diabetes; individuals with A1c 5.7 to <6.5% are at highest risk (prediabetes range). For impaired fasting glucose (prediabetes), FPG range 100-125 mg/dL; impaired glucose tolerance two-hour PG 140-199 mg/dL.FPG ≥126 mg/dL; 2-h PG ≥200 mg/dL (75 g OGTT); A1c ≥6.5%; Prediabetes: A1c 5.7–<6.5%; IFG 100–125 mg/dL; IGT 2-h PG 140–199 mg/dL

These thresholds reflect ADA/AACE guidance and policy background; diagnostic use of random PG ≥200 mg/dL with symptoms also applies.

General diagnostic criteria for diabetes and prediabetes (AACE summary)

Diagnosis and prediabetes identification per AACE/ACE recommendations:

AACE summary - Diagnostic and prediabetes criteria

Prediabetes definitions (any of the following): Impaired fasting glucose (IFG): FPG 100–125 mg/dL; Impaired glucose tolerance (IGT): 2-h PG 140–199 mg/dL after 75-g load; A1C 5.7%–6.4% (A1C recommended for screening only).IFG 100–125 mg/dL; IGT 140–199 mg/dL; A1C 5.7–6.4%
Diagnosis of prediabetes should be confirmed with glucose testing.

AACE notes on testing and confirmation: AACE: In individuals with discordant results, repeat the test; when one abnormal OGTT value meets diabetes criteria, repeat the test to confirm. Fasting glucose and plasma glucose should be measured in venous plasma in accredited labs.

Gestational diabetes screening and diagnosis

Recommendations for screening timing and diagnostic approaches in pregnancy:

Pregnancy screening overview: Screen individuals planning pregnancy with risk factors; consider testing all for undiagnosed prediabetes/diabetes. Test individuals with risk factors before 15 weeks gestation; consider testing all individuals for undiagnosed diabetes at first prenatal visit.

Early screening for abnormal glucose metabolism using fasting glucose 110–125 mg/dL or A1C 5.9%–6.4% identifies higher-risk individuals.

Diagnostic approaches for GDM (AACE Recommendation 1.6): Screen for GDM at 24–28 weeks in pregnant individuals not previously found to have diabetes. One-step: 75-g 2-hour OGTT after ≥8 h fasting; diagnostic cutoffs: FPG ≥92 mg/dL, 1-h PG ≥180 mg/dL, 2-h PG ≥153 mg/dL (one or more abnormal). Two-step: nonfasting 1-h 50-g GCT with 1-h PG threshold 130 or 140 mg/dL; if positive, 3-h 100-g OGTT with thresholds: FPG ≥95 mg/dL, 1-h ≥180 mg/dL, 2-h ≥155 mg/dL, 3-h ≥140 mg/dL (diagnosis requires two or more abnormal).One-step: FPG ≥92 mg/dL; 1-h ≥180 mg/dL; 2-h ≥153 mg/dL (one or more abnormal). Two-step: GCT 1-h threshold 130 or 140 mg/dL; 3-h OGTT: FPG ≥95;1-h ≥180;2-h ≥155;3-h ≥140 (two or more abnormal).

In absence of unequivocal hyperglycemia, a positive screen requires two abnormal values; if only one abnormal in OGTT, repeat to confirm.

Postpartum testing recommendation: Test individuals with GDM for persistent diabetes or prediabetes at 4–12 weeks postpartum using 75-g OGTT and nonpregnancy criteria; individuals with history of GDM should have lifelong screening every 1–3 years.4–12 weeks postpartum OGTT; ongoing screening every 1–3 years

OGTT preferred postpartum because A1C may be affected by pregnancy-related RBC turnover.

Screening intervals and populations

Recommendations for whom to screen and how often:

USPSTF and adult screening: USPSTF: screen adults aged 35–70 who are overweight or obese; consider screening every 3 years if initial normal. ADA/AACE: screen adults with risk factors beginning at age 35 (or age 45 per earlier guidance); repeat testing at least every 3 years for normal results; consider annual screening if two or more risk factors.Screening interval: every 3 years (general); annual if multiple risk factors; start age 35 for most adults

Endocrine Society: screen patients ≥65 years every 2 years.

Endocrine Society and older adults: Endocrine Society: screen patients ≥65 years every 2 years (FPG and/or A1C), with caution interpreting A1C in older adults due to altered RBC turnover.Every 2 years for ≥65 years

Children and adolescents screening guidance: Children/adolescents: risk-based screening after onset of puberty or ≥10 years in youth with overweight (BMI ≥85th percentile) or obesity (BMI ≥95th) and at least one additional risk factor (maternal history of diabetes/GDM, family history of T2D, race/ethnicity, signs of insulin resistance or related conditions). USPSTF (2022): insufficient evidence to recommend routine screening in asymptomatic children/adolescents (I statement).Start ≥10 years or after puberty for at-risk youth; repeat at minimum every 3 years if normal

Diagnostic test selection and assay standards

Guidance on appropriate tests and assay quality:

Appropriate diagnostic tests: FPG, 2-h PG during 75-g OGTT, and A1C are appropriate for diagnostic screening; detection rates vary between tests.

When using OGTT as a screen, ensure adequate carbohydrate intake prior to testing.

A1C assay requirements: A1C should be performed using NGSP-certified methods traceable to the DCCT reference assay. Point-of-care A1C may be NGSP certified and FDA-cleared but must meet CLIA requirements and be performed by trained personnel with proficiency testing.

Point-of-care A1C for screening/diagnosis restricted to FDA-approved devices in CLIA-certified settings.

Laboratory and sample recommendations: Fasting glucose should be measured in venous plasma when used to establish diagnosis; plasma glucose should be measured in accredited laboratories for diagnosis/screening.Venous plasma for FPG; accredited laboratory testing

Conditions affecting A1C reliability: A1C may be unreliable in conditions with altered red blood cell turnover (e.g., hemoglobin variants, pregnancy, G6PD deficiency, advanced CKD, hemodialysis, recent transfusion, erythropoietin therapy, hemolytic anemia) and should not be used for diagnosis in those settings; plasma glucose criteria preferred.

Alternative biomarkers (fructosamine, glycated albumin) may be considered for monitoring when A1C unreliable.

Monitoring frequency and glycemic targets

Recommendations for monitoring frequency and targets:

Monitoring frequency: Assess glycemic status by A1C and/or CGM metrics at least twice a year; assess more frequently (e.g., every 3 months) for those not meeting goals, with frequent/severe hypoglycemia, therapy changes, or growth in youth. Assess at least quarterly for patients whose therapy recently changed or who are not meeting goals.A1C frequency: ≥2 times/year stable; every 3 months if unstable or therapy change

A1C targets and special populations: A1C goals should be individualized. Many children: A1C <7% (53 mmol/mol) appropriate. Pregnancy targets: fasting <95 mg/dL; 1-h <140 mg/dL or 2-h <120 mg/dL; A1C ideally <6% if achievable without hypoglycemia (may relax to <7%). Monitor A1C more frequently (e.g., monthly) in pregnancy.Pregnancy fasting <95 mg/dL; 1-h <140 mg/dL; 2-h <120 mg/dL; pregnancy A1C goal <6% if achievable

Inpatient and perioperative monitoring: Perform A1C on admitted people with diabetes or hyperglycemia (>140 mg/dL) if no A1C in prior 3 months. Inpatient POC glucose monitoring before meals if eating, every 4–6 h if not eating, and every 30–120 min for IV insulin. Perioperative blood glucose goal 100–180 mg/dL within 4 h of surgery; do not use CGM alone during surgery.Inpatient random BG >140 mg/dL triggers A1C if none in prior 3 months; perioperative BG 100–180 mg/dL

Elective surgery A1C goal <8% when possible.

Special populations and conditions

Group-specific recommendations:

Cystic fibrosis-related diabetes (CFRD): CFRD: annual OGTT screening beginning at age 10 in patients with CF not previously diagnosed with CFRD; A1C is not recommended for screening due to low sensitivity; begin annual monitoring for complications five years after CFRD diagnosis.Annual OGTT from age 10

Alternate biomarkers perform poorly for CFRD screening.

HIV: screen with FPG before starting ART, at switching ART, and 3–6 months after start/switch; if normal, check FPG annually. A1C may underestimate glycemia and is not recommended for diagnosis in people with HIV.FPG baseline, 3–6 months after start/switch, then annually if normal

Liver disease / NASH: Adults with T2D or prediabetes should be screened for clinically significant liver fibrosis using FIB-4; indeterminate/high FIB-4 → liver stiffness measurement (transient elastography) or ELF; refer to gastroenterology/hepatology for indeterminate/high risk.Use FIB-4 for initial stratification; follow-up with transient elastography or ELF as indicated

CKD: KDIGO: use A1C to monitor patients with diabetes and CKD twice a year or up to four times a year if target not met or therapy changed; A1C accuracy declines with advanced CKD/dialysis and targets should be individualized (<6.5%–<8.0% for non-dialysis CKD).A1C monitoring 2–4 times/year depending on control; individualized targets for CKD

Monogenic diabetes: Consider evaluation for monogenic diabetes in any child or young adult with atypical presentation, clinical course, or response to therapy (eg, neonatal diabetes, MODY).

Perioperative medication management

Recommendations for handling diabetes medications around surgery:

Perioperative medication management: Hold metformin on day of surgery. Discontinue SGLT2 inhibitors 3–4 days before surgery. Hold other oral glucose-lowering agents the morning of surgery. For insulin: give one-half of NPH evening-before dose or 75–80% of long-acting analog insulin doses or adjust pump basal based on diabetes type and clinical judgment. Monitor blood glucose at least every 2–4 h while NPO and dose with short- or rapid-acting insulin as needed; consider 25% reduction of basal insulin evening before surgery to lower hypoglycemia risk.SGLT2 discontinue 3–4 days preop; hold metformin day of surgery; insulin dose adjustments as described

CGM should not be used alone during surgery; perioperative BG goal 100–180 mg/dL within 4 h of surgery.

GDM one-step (75-g OGTT) cutoffsFPG >=92 mg/dL; 1-hour >=180 mg/dL; 2-hour >=153 mg/dL (one or more abnormal)

GDM two-step (3-h 100-g OGTT) cutoffsFPG >=95 mg/dL; 1-hour >=180 mg/dL; 2-hour >=155 mg/dL; 3-hour >=140 mg/dL (diagnosis requires >=2 abnormal)

Early pregnancy screening thresholds (identify high risk)Fasting 110-125 mg/dL; A1c 5.9%-6.4%

Pregnancy glycemic targetsFasting <95 mg/dL; 1-hour postprandial <140 mg/dL; 2-hour postprandial <120 mg/dL; A1c goal ideally <6% if safe (may relax to <7%)

Perioperative blood glucose target100-180 mg/dL within 4 hours of surgery

Documentation Required

Annual OGTT for cystic fibrosis patients (age ≥10)

Annual OGTT is recommended and meets coverage criteria for individuals with cystic fibrosis aged 10 years and older for screening of cystic fibrosis–related diabetes.

Indicated: CF patients age >= 10 years; test: 75 g OGTT; frequency: annually.

Documentation Required

Use certified A1C methods and CLIA standards

Hemoglobin A1c testing must be performed using methods certified by an appropriate standardization program and in compliance with CLIA requirements to ensure accuracy and comparability of results.

Affected code: 83037 (Hemoglobin; glycosylated (A1c)).
Use NGSP- or IFCC-traceable methods where available; avoid nonstandardized POC methods for diagnostic purposes unless certified.

Documentation Required

Use venous plasma and accredited labs for diagnostic glucose measurements

For diagnostic plasma glucose measurements (FPG, OGTT, 2-hour plasma glucose), use venous plasma collected and analyzed by accredited clinical laboratories. Point-of-care capillary measurements may be used for screening or monitoring but are not acceptable for definitive diagnostic confirmation unless specified by guidance.

Use venous plasma in an accredited lab (e.g., CAP-accredited).
Avoid capillary/POC samples for diagnostic confirmation unless explicitly allowed.

Billing Rule

Inpatient A1C testing when no recent result

Inpatient hemoglobin A1c testing is allowed when no prior recent A1c result is available to guide immediate inpatient management; document lack of a recent result and the clinical need for the test to support billing.

Affected code: 83037 (Hemoglobin; glycosylated (A1c)).
Document: no A1c within the recommended interval and how the inpatient result will impact care.

Documentation Required

HIV patient screening schedule

Follow recommended HIV screening schedule for persons with HIV or on antiretroviral therapy: screen for diabetes at baseline (upon diagnosis or initiation of ART) and periodically thereafter per clinical guidelines due to increased risk related to HIV and some antiretroviral agents.

Baseline screening at HIV diagnosis or ART initiation; ongoing periodic screening as clinically indicated.

Documentation Required

Liver fibrosis risk stratification in diabetes

For persons with diabetes, assess risk for liver fibrosis (e.g., NAFLD/MASLD) using validated noninvasive risk stratification tools (FIB-4, ELF, transient elastography) as part of routine care to identify those needing referral for hepatology evaluation.

Consider FIB-4 and ELF scores and document results; refer if high-risk thresholds met.

Prior Authorization

Postpartum OGTT for patients with gestational diabetes

Postpartum OGTT for individuals with gestational diabetes mellitus meets coverage criteria to evaluate for persistent glucose intolerance; ensure documentation of the GDM diagnosis and timing of the postpartum test. Prior authorization may be required where benefit rules specify.

Prior authorization: check benefit for postpartum OGTT after GDM.
Timing: typically 4–12 weeks postpartum using 75 g OGTT.

Documentation Required

Perioperative medication management documentation

Document perioperative medication management considerations (e.g., holding/metformin, insulin adjustments) and the rationale for preoperative glucose/A1c testing when used to guide perioperative glycemic management.

Include medication changes and how test results will inform perioperative care.

US prevalence (2021)38.4 million Americans (11.6%); 29.7M diagnosed, 8.7M undiagnosed

Economic cost (2022)$413 billion

ADA Standards of CareMultiple chapter recommendations cited (screening, diagnosis, gestational diabetes, monitoring) - ADA 2024/2025 referenced

AACE / AACE-ACEDiagnostic thresholds and GDM one-step/two-step approaches referenced

KDIGOA1c monitoring frequency guidance for CKD and individualized targets cited