Introduction: The Changing Landscape of Pediatric Diabetes Monitoring

Effective glycemic monitoring is a cornerstone of pediatric diabetes care, directly influencing long-term outcomes and quality of life. For decades, hemoglobin A1c (HbA1c) has served as the standard metric for assessing average glucose levels over the preceding two to three months. However, in children with diabetes—whether type 1 or type 2—relying solely on HbA1c leaves critical gaps. It fails to capture short-term fluctuations, hypoglycemic events, postprandial excursions, and glycemic variability, all of which are especially relevant during growth, puberty, and the unpredictable lifestyle patterns of childhood. Recent advances in biomarker research now offer more precise, real-time insights into glycemic status. This article reviews emerging biomarkers that promise to enhance monitoring, reduce complications, and personalize treatment for children with diabetes.

Traditional Glycemic Monitoring and Its Limitations in Pediatrics

HbA1c reflects the percentage of hemoglobin that is glycated, correlating with average blood glucose over 8–12 weeks. In pediatric care, HbA1c targets guide therapy adjustments and predict microvascular complication risk. However, the test has well-documented limitations in children. It provides no information about glycemic variability, the frequency or severity of hypoglycemia, or the timing of hyperglycemic spikes. Conditions like anemia, hemoglobin variants (including elevated HbF in young children), recent transfusions, and renal impairment can skew results. Moreover, during puberty—when insulin resistance surges due to growth hormone—HbA1c may lag behind clinical reality, leading to delayed therapy adjustments. Children with rapidly changing insulin needs, such as during intercurrent illness or sports seasons, are poorly served by a metric that averages over months.

Self-monitoring of blood glucose (SMBG) offers snapshots but requires frequent fingersticks and cannot capture interstitial fluid dynamics or overnight trends. These gaps have driven the search for additional biomarkers that can complement or, in specific scenarios, replace HbA1c for more agile management in pediatric diabetes.

The Need for More Dynamic Biomarkers in Children

Children with diabetes face unique challenges: variable exercise patterns, unpredictable eating behaviors, and hormonal shifts during growth spurts. Episodes of severe hypoglycemia can impair cognitive development, while sustained hyperglycemia accelerates complication risk. A biomarker that reflects short-term glycemic control—over days to weeks—can help clinicians and families make timely decisions. Furthermore, detecting glycemic variability and postprandial excursions allows for targeted interventions, such as adjusting meal-time insulin boluses or recommending specific carbohydrate sources. Emerging biomarkers are being validated to address these needs, offering more granular and actionable data than HbA1c alone.

The pediatric endocrinologist must consider not only the mean glucose but also the shape of the glucose curve. For example, two children with the same HbA1c can have vastly different experiences: one with stable glucose and another with wide swings. The latter is at higher risk for oxidative stress, inflammation, and endothelial damage, making variability a key target. Biomarkers that capture oscillations over hours to weeks are essential for modern pediatric diabetes management.

Emerging Biomarkers for Short-Term Glycemic Assessment

Fructosamine

Fructosamine measures total glycated serum proteins, primarily albumin, reflecting average glucose over the preceding 2–3 weeks. This shorter time window is especially useful when evaluating recent therapeutic changes—for example, after starting a new insulin regimen, adjusting pump settings, or initiating an exercise program. In pediatric studies, fructosamine has shown good correlation with HbA1c and with mean glucose derived from continuous glucose monitoring (CGM). It is unaffected by erythrocyte lifespan or hemoglobin variants, making it suitable for children with coexisting conditions such as chronic kidney disease, sickle cell trait, or hemolytic anemias.

However, fructosamine values can be influenced by alterations in protein turnover, such as during growth spurts, hyperthyroidism, or liver disease. Clinicians must interpret results in context. Recommended cutoff values for pediatric populations are still being standardized, but research suggests that a fructosamine level of >300 µmol/L often corresponds to an HbA1c above 7% in children with type 1 diabetes. Some studies propose that combining fructosamine with HbA1c improves prediction of mean glucose beyond either test alone. An external link to a recent pediatric study: Fructosamine as a short-term glycemic marker in children with type 1 diabetes: correlation with continuous glucose monitoring.

1,5-Anhydroglucitol (1,5-AG)

1,5-AG is a naturally occurring sugar alcohol that competes with glucose for renal tubular reabsorption. During hyperglycemia (especially above the renal threshold of ~180 mg/dL), glucose outcompetes 1,5-AG, leading to increased urinary excretion and a drop in serum levels. This makes 1,5-AG a sensitive marker for postprandial hyperglycemic excursions and glycemic variability over the prior 1–2 weeks. In pediatric cohorts, lower 1,5-AG levels have been associated with higher HbA1c, greater glycemic variability measured by CGM, and increased risk of complications. The test is approved for clinical use in some countries but is not yet widely adopted in pediatrics.

A key limitation is that 1,5-AG levels are reduced in renal impairment and may be affected by diets high in certain sugars (e.g., galactose, mannose). Despite these caveats, 1,5-AG offers an intermediate-term view that complements both HbA1c and fructosamine. It is particularly useful in children who have acceptable HbA1c but suffer frequent postprandial spikes—a common pattern in adolescents with high carbohydrate intake. For more on its pediatric utility, see 1,5-Anhydroglucitol as a marker for glycemic variability in children with type 1 diabetes: a cross-sectional study.

Glycated Albumin

Glycated albumin (GA) is a more specific measure compared to total fructosamine because it isolates the glycation of albumin alone. Albumin has a half-life of about 14–20 days, so GA reflects glucose control over roughly 2–4 weeks. GA is usually reported as a percentage of total albumin, which reduces the impact of variations in protein synthesis. Studies in children with type 1 diabetes have shown GA to be closely correlated with CGM-derived mean glucose and time-in-range. Some authors propose GA as a substitute for HbA1c in situations where HbA1c is unreliable (e.g., hemolysis, recent transfusion, pregnancy).

The test is available in some clinical laboratories but remains less familiar to pediatric endocrinologists. Standardized reference ranges for children are still under development, but initial data suggest that a GA > 15% may correspond to suboptimal control. One advantage: GA is less affected by fluctuations in albumin levels compared to fructosamine, although both can be altered by nephrotic syndrome or malnutrition. A recent consensus paper discusses GA and other emerging biomarkers: Emerging biomarkers for glycemic control – American Diabetes Association technical report.

Advanced Metrics from Continuous Glucose Monitoring

Continuous glucose monitoring (CGM) systems provide a wealth of interstitial glucose data—typically updated every 5 minutes. While CGM itself is a technology rather than a biomarker, the derived metrics have become essential surrogates for glycemic status. The most widely adopted is time-in-range (TIR), defined as the percentage of readings between 70 and 180 mg/dL. TIR has been validated as a predictor of diabetes complications and is now recommended as a key outcome measure by the International Consensus on TIR. In children, targets are set at >70% TIR for most age groups, although goals may differ for very young children to minimize hypoglycemia risk.

Other important CGM-derived biomarkers include:

  • Time-below-range (TBR): percentage of readings <70 mg/dL (level 1 hypoglycemia) or <54 mg/dL (level 2 hypoglycemia). Minimizing TBR is critical to avoid seizures, loss of consciousness, and cognitive impairment.
  • Time-above-range (TAR): percentage of readings >180 mg/dL and >250 mg/dL. High TAR is linked to microvascular complications and glycemic variability.
  • Glycemic variability indices: standard deviation (SD) of glucose readings, coefficient of variation (CV), and mean amplitude of glycemic excursions (MAGE). Higher variability is associated with oxidative stress and inflammation, independent of mean glucose. CV <36% is often targeted as optimal.

The ambulatory glucose profile (AGP) is a standardized report that summarizes these metrics, enabling clinicians to visualize patterns. Integrating CGM metrics with traditional biomarkers offers a comprehensive picture of glucose dynamics. However, CGM is not yet affordable universally, and sensor accuracy can be reduced in the youngest children due to thinner skin and movement artifacts. Nonetheless, guidelines increasingly emphasize TIR as a primary endpoint in clinical trials and daily management. The Diabetes UK time-in-range guidelines provide practical targets for pediatric care.

Novel Protein-Based and Genetic Biomarkers

MicroRNAs (miRNAs)

MicroRNAs are small non-coding RNA molecules that regulate gene expression. Specific circulating miRNAs—such as miR-21, miR-126, and miR-146a—have been found to be dysregulated in children with type 1 diabetes and correlate with glycemic control. Elevated miR-21 levels, for example, are associated with increased inflammatory signaling and may reflect beta-cell stress. miR-126 is involved in endothelial integrity, and its reduction has been linked to vascular complications. While still in the research phase, miRNA profiles could eventually serve as early indicators of glycemic worsening or complication risk. Currently, no clinical miRNA test is available for routine diabetes monitoring, but multiple trials are exploring their prognostic value. A key advantage: miRNAs can be measured in serum, plasma, or even dried blood spots, making them potentially suitable for pediatric point-of-care testing.

Inflammatory Biomarkers

Chronic hyperglycemia triggers low-grade inflammation, and markers such as high-sensitivity C-reactive protein (hs-CRP), interleukin-6 (IL-6), and tumor necrosis factor-alpha (TNF-α) are elevated in children with suboptimal glycemic control. These inflammatory biomarkers can supplement glucose metrics by indicating the cumulative metabolic impact of hyperglycemia. However, their specificity is low, as they rise in many conditions (infections, obesity, adiposity). Combining inflammatory markers with CGM or fructosamine may provide a more holistic risk assessment. For instance, a child with elevated hs-CRP and high glycemic variability may benefit from more aggressive anti-inflammatory lifestyle interventions or early screening for complications.

Lipidomic and Metabolomic Profiles

Advanced analytical techniques can identify hundreds of lipid species and metabolites in blood. Some studies have linked specific ceramides and phospholipids to insulin resistance and poor glycemic control in youth with type 2 diabetes. For type 1 diabetes, changes in branched-chain amino acid concentrations have been observed during hyperglycemia. Metabolomic profiling may reveal distinct signatures of diabetic ketoacidosis risk or nephropathy progression. Although these approaches are not yet ready for clinical use, they represent a frontier for personalized medicine. An overview of metabolomic biomarkers can be found in Metabolomic profiling for glycemic control in pediatric diabetes: a review.

Clinical Integration and Challenges

Adopting new biomarkers into everyday pediatric diabetes care requires overcoming several hurdles. Standardization is paramount: without uniform assay calibration, results from different laboratories cannot be compared. Fructosamine and GA assays vary widely between manufacturers; efforts to harmonize them are underway through organizations like the International Federation of Clinical Chemistry (IFCC). Age-specific reference ranges are essential because children at different developmental stages have distinct protein turnover rates, renal thresholds, and hematocrit levels. An abnormal value for a prepubertal child may be normal for an adolescent.

Cost and accessibility also play roles. While HbA1c is inexpensive and widely available, fructosamine, GA, and 1,5-AG are more expensive and not routinely reimbursed in many healthcare systems. CGM sensors, though increasingly covered by insurance in many countries, still represent a significant outlay for some families. There is also a need for clinician education: many pediatric endocrinologists are unfamiliar with interpreting fructosamine or 1,5-AG results in the context of insulin adjustments. Decision-support tools that integrate multiple biomarkers into a single actionable score would help bridge this gap.

Another challenge is interpreting multiple biomarkers simultaneously. If HbA1c is 7.5%, fructosamine is 320 µmol/L, and TIR is 55%, which data point should guide the next therapy change? Current guidelines recommend using HbA1c as the primary metric, but emerging evidence suggests that combining TIR with a short-term biomarker can improve decision-making. For example, a patient with acceptable HbA1c but high glycemic variability may benefit from adjusting prandial insulin or from a sustained hyperglycemia pattern. Machine learning algorithms that weigh these factors are in development.

Pediatric data gaps remain. Most biomarker validation studies involve adults; extrapolating to children without dedicated trials is risky. The National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK) has funded several pediatric-specific studies, including the SEARCH for Diabetes in Youth and the TODAY study, which have begun to incorporate novel biomarkers. As more data emerge, clinical practice guidelines will evolve to recommend appropriate contexts for each test.

Future Directions

The future of glycemic monitoring in pediatric diabetes is moving toward a multi-biomarker panel approach, integrating HbA1c, fructosamine or GA, CGM-derived metrics (TIR, TBR, CV), and possibly inflammatory markers (hs-CRP, IL-6) into a single, easy-to-interpret composite score. Such a score could be calculated automatically in electronic health records or diabetes management apps. Machine learning algorithms can synthesize these data to predict impending hypo- or hyperglycemic events and recommend real-time adjustments. Several smartphone apps and telemedicine platforms already incorporate CGM data and aim to add fructosamine or GA results from intermittent fingerstick samples.

Wearable technologies are also advancing: non-invasive sensors that analyze sweat, tears, or saliva for glucose and other metabolites (e.g., lactate, ketones) are in development. If validated, these could provide continuous, pain-free monitoring for children, especially those with needle phobia. Another frontier is the use of proteomic and genomic markers to identify children at highest risk for complications, enabling early intervention even before conventional metrics show deterioration. For example, a child with a genetic predisposition for diabetic nephropathy could be monitored more closely with urinary biomarkers like KIM-1 or NGAL.

Personalized therapy will become more achievable. A child with frequent postprandial excursions might be monitored primarily with 1,5-AG and CGM TIR, while an adolescent with unstable glycemia due to pubertal hormones could benefit from weekly GA checks and careful tracking of TBR. Tailoring the biomarker panel to the individual’s phenotype will optimize outcomes and reduce burden.

Conclusion

Emerging biomarkers such as fructosamine, glycated albumin, 1,5-anhydroglucitol, and comprehensive CGM metrics are transforming the landscape of pediatric diabetes management. They offer shorter-term, more dynamic reflections of glycemic control than HbA1c alone, allowing clinicians and families to respond more quickly to changes in a child's diabetes status. While challenges related to standardization, cost, and pediatric-specific data remain, ongoing research and technological innovation are progressively overcoming these barriers. Incorporating these biomarkers into routine care promises to reduce hypoglycemia and hyperglycemia, improve quality of life, and ultimately delay or prevent complications. For healthcare providers caring for children with diabetes, staying informed about these developments is essential to delivering state-of-the-art, personalized treatment.