Hemoglobin A1c (HbA1c) is commonly utilized for guiding diabetes management and diagnosis, as blood sampling can be done at any time of day, the levels are consistent, and the assays are standardized (Ford CN, Leet RW, Kipling LM, et al. , 2019). And it shows your average blood sugar level for the past 4 to 6 weeks.

In general, the reference range for glycated hemoglobin (HbA1c) in healthy individuals is 4% to 6%. Elevated levels of glycated hemoglobin beyond this normal range often indicate the possibility of diabetes or impaired glucose tolerance.

Pregnant Women

During early pregnancy, increased secretion of erythropoietin accelerates the metabolism of red blood cells, leading to a shorter lifespan and increased production of immature red blood cells. The average lifespan of red blood cells decreases, which complicates glycated hemoglobin measurements.

The reference range for glycated hemoglobin is established based on a normal red blood cell lifespan of 120 days. Prolonged red blood cell lifespan increases the contact time between glucose and hemoglobin, resulting in higher glycated hemoglobin levels. Conversely, shortened red blood cell lifespan reduces this contact time, leading to lower glycated hemoglobin levels. The American Diabetes Association recommends a preconception glycated hemoglobin level between 6% and 6.5%. During pregnancy, glycated hemoglobin levels are predictive of maternal and fetal complications. Normally, the ideal levels during pregnancy will be lower than normal range during the first and second trimesters

O’Connor et al. defined normal HbA1c ranges for pregnant Caucasian women as <5.4% in the first trimester, <5.4% in the second trimester, and <5.7% in the third trimester.

Therefore, routine glycated hemoglobin screening during pregnancy is not recommended according to clinical guidelines.

For patients with previously undiagnosed diabetes but with an HbA1c ≥ 6.5% detected during pregnancy, they can be diagnosed with pregestational diabetes mellitus (PGDM) combined with pregnancy.

Children and Teenager

Although type 1 diabetes is predominant in children and adolescents, the incidence of type 2 diabetes has been notably increasing in recent years. The diagnostic criteria for diabetes in children and adolescents follow a process of diagnosis before classification, with criteria consistent with those for adults, by differentiation based on clinical features.

For children and adolescents, glycated hemoglobin (HbA1c) is an important monitoring indicator for determining, formulating treatment plans, and setting blood sugar control targets. Metabolically stable patients (HbA1c < 8.5% and no significant symptoms) can initially be treated with metformin, while patients with unstable metabolism require insulin therapy. If patients still cannot achieve the target of HbA1c < 6.5% after 3-4 months of metformin treatment, the addition of basal insulin is strongly recommended. To ensure normal growth and development in children and adolescents and to avoid hypoglycemia, it is recommended that those treated with oral medications strive to control HbA1c levels below 7.0%, while the control target for those receiving insulin therapy can be appropriately relaxed.

Furthermore, according to the "Guidelines for the Prevention and Treatment of Type 2 Diabetes," it is recommended that affected children undergo HbA1c testing at least twice a year. If a child is receiving insulin therapy or if blood sugar control is not meeting standards, HbA1c should be tested every 3 months.

Elder Population

The elderly population aged 60 and above is a key target for diabetes prevention and management. The prevalence of diabetes is high among the elderly, and elderly diabetic patients are at increased risk of hypoglycemia. Additionally, their ability to perceive hypoglycemia and self-regulate and cope with it after occurrence is diminished, making them more prone to unconscious hypoglycemia, nocturnal hypoglycemia, and severe hypoglycemia. Therefore, glycemic control targets for elderly diabetic patients should be appropriately relaxed, and efforts should be made to select antidiabetic medications with low risk of hypoglycemia. Close monitoring of blood glucose fluctuations is essential. When dealing with elderly diabetic patients, it is recommended to comprehensively assess their health status to determine individualized glycemic control targets and treatment strategies.

For relatively healthy elderly diabetic patients who are only treated with oral antidiabetic medications with low risk of hypoglycemia, it may be considered to control glycated hemoglobin levels to near-normal levels. However, for elderly diabetic patients with moderately impaired health or relatively poor health status, their glycemic control targets may be appropriately relaxed, but symptoms and potential acute complications caused by hyperglycemia should be avoided.

Considering that patients are more likely to be exposed to hyperglycemia more frequently, leading to the occurrence of various acute complications, it is not recommended to set glycated hemoglobin targets exceeding 8.5%.

Summary:
Different populations have specific blood glucose control targets, and blindly formulating treatment plans based on conventional reference ranges may actually lead to hypoglycemia and, consequently, more severe consequences. When dealing with these special populations, it is necessary to comprehensively assess the patient's health status and tailor individualized blood glucose control targets and management plans for each patient.

Poclight Hemoglobin A1c (HbA1c) Test

Assay Specifications

C5000

• Fast: First result in 3 mins
• Accurate
• Room temperature storage 
• Test upon arrival

Reference

Ford CN, Leet RW, Kipling LM, Rhee MK, Jackson SL, Wilson PWF, Phillips LS, Staimez LR. Racial differences in performance of HbA1c for the classification of diabetes and prediabetes among US adults of non-Hispanic black and white race. Diabet Med. 2019 Oct;36(10):1234-1242. doi: 10.1111/dme.13979. Epub 2019 Jul 15. PMID: 31187544; PMCID: PMC7282707