What is an HbA1c Test? Why is the 3-Month Blood Sugar Screening Requested?

The clearest answer to the question of what HbA1c is is that it is a laboratory test measuring the amount of sugar attached to the hemoglobin in your red blood cells, revealing your average blood sugar level over the past two to three months. Commonly known as the 3-month blood sugar test, this measurement is one of the most reliable ways to determine diabetes risk because it is not affected by sudden, momentary fluctuations. Unlike your fasting blood sugar, which only shows your condition at the exact moment your blood is drawn, HbA1c provides your doctor with a much broader and clearer picture of your long-term metabolic control.

• The HbA1c test reflects your average blood sugar levels over the past 2 to 3 months.
• In healthy individuals, this value is expected to be below 5.7 percent.
• Values between 5.7 and 6.4 percent indicate a risk of prediabetes (hidden sugar).
• Results of 6.5 percent and above are generally used to diagnose diabetes.
• Blood can be drawn at any time of the day for this test; when done alone, it does not require fasting.

What is HbA1c and How Does it Work in the Body?

For the organs in our body to function healthily, they need energy, namely glucose. After the food we consume is digested, it joins the bloodstream as glucose. This glucose in the bloodstream tends to stick to the hemoglobin protein inside the red blood cells (erythrocytes), which are responsible for carrying oxygen to the tissues. The more sugar circulating in your blood, the more sugar binds to the hemoglobin. In medicine, this process is called glycation.

The average lifespan of red blood cells in the human body is about 120 days. Therefore, measuring the amount of sugar bound to the hemoglobin protein reveals what levels your blood sugar has averaged over a retrospective window of 90 to 120 days. Overindulging in traditional Turkish sweets like baklava for a few days or feeling stressed on the morning of the test will not suddenly change this value. Thanks to this feature, the 3-month blood sugar test is considered the gold standard both in diagnosing diabetes and in monitoring how well existing diabetes patients are adapting to their treatment.

Causes of High HbA1c and Risk Factors

Extensive diabetes screening data from the Ministry of Health clearly shows how common and stealthily progressing the problem of high blood sugar can be in our society. High HbA1c basically occurs when sugar accumulates in the blood as a result of the pancreas failing to produce enough insulin or the body's cells resisting the insulin produced (insulin resistance). The sugar that cannot enter the cells remains in the bloodstream, binds to the hemoglobin cells, and causes the test result to be high.

At the top of the major risk factors paving the way for this elevation are a sedentary lifestyle and an unbalanced diet. Excessive consumption of simple carbohydrates and refined sugars, in particular, forces the pancreas to constantly secrete insulin, exhausting it over time. Having a family history of type 2 diabetes multiplies the risk by increasing genetic predisposition. Excess weight, especially fat around the waist, is one of the most important triggers of insulin resistance. Furthermore, advancing age, high blood pressure, high cholesterol, and metabolic problems like sleep apnea are also among the factors that disrupt the blood sugar balance and pave the way for elevated HbA1c values.

Early and Advanced Symptoms of Diabetes

High blood sugar can progress silently for years without causing any noticeable complaints, especially during the initial prediabetes (hidden sugar) stage. However, as the values approach or cross the diabetes threshold, the body begins to send out certain signals. Among the most common early symptoms are a feeling of excessive thirst (polydipsia) and frequent urination (polyuria). The kidneys work intensely to filter out and excrete the excess sugar accumulated in the blood, which leads to excess water being expelled from the body and a constant feeling of dehydration.

As the disease progresses, because the cells cannot use the abundant sugar in the blood as energy, the person constantly feels tired, sluggish, and exhausted. Sleepiness setting in shortly after meals, unexplained weight loss, or conversely, weight gain accompanied by a constant feeling of hunger are frequently seen. Complaints such as blurred vision, tingling or numbness in the feet or hands, and dry, itchy skin are reflections of the negative effects of high sugar on the nerves and blood vessels. Additionally, minor cuts or wounds taking much longer than normal to heal is a significant symptom indicating that the immune system has weakened and the blood sugar balance has been disrupted.

How is the Diabetes Screening Test Diagnosed at the Hospital?

For individuals suspected of having diabetes or undergoing a routine health check-up, the diagnostic process is quite comfortable and fast. When you visit the hospital for a diabetes screening test, simply drawing a small tube of blood from a vein in your arm is sufficient. Since the HbA1c test is based on the long life cycle of red blood cells, it can theoretically be done at any time of the day, even on a full stomach. However, to see the complete metabolic picture, physicians generally request this test alongside other examinations such as fasting blood sugar, insulin levels, and a lipid profile (cholesterol). For this reason, it is frequently preferred that you come to the hospital with an overnight fast of 8 to 10 hours.

The collected blood sample is analyzed with special devices in the laboratory, and the results are usually available on the same day. Your physician does not just look at the laboratory result; they make a comprehensive evaluation by also listening to your family history, weight, lifestyle, and any complaints you might have. If the results fall within the prediabetes (hidden sugar) range, an early intervention plan is created to prevent the full development of diabetes. If diabetes is diagnosed, an appropriate treatment protocol is determined based on the type of the disease (Type 1 or Type 2).

Treatment Approaches to Balance Blood Sugar

Bringing the HbA1c value down to healthy limits and bringing diabetes under control requires a holistic approach where medical treatment and lifestyle changes are carried out together. The cornerstone of the treatment is medical nutrition therapy. Instead of white flour, refined sugar, and processed foods, it is essential to switch to a diet consisting of whole grains, fibrous vegetables, healthy fats, and high-quality protein sources. Especially considering the harms of sugary drinks, staying away from acidic beverages and ready-made fruit juices is one of the biggest steps to be taken in blood sugar control.

Regular physical activity breaks insulin resistance by allowing the muscles to use sugar as energy and directly contributes to lowering HbA1c levels. Exercises such as a brisk walk or swimming for at least 150 minutes a week are recommended. In cases where lifestyle changes are not enough, your physician may prescribe oral diabetes medications (oral antidiabetics). These medications can suppress the liver's sugar production, increase insulin secretion from the pancreas, or improve the cells' sensitivity to insulin. For patients with advanced-stage type 2 diabetes or type 1 diabetes, it may be necessary to start insulin injection therapy to replace the missing insulin.

Complications and Risk Groups

Having high blood sugar for a long time damages all the vascular and nerve networks in the body, leading to serious complications. Diabetic retinopathy can develop as the capillaries in the retina of the eye are damaged, and this condition can even lead to permanent vision loss. The deterioration of the filtering units in the kidneys causes diabetic nephropathy, while damage to the nerve endings leads to diabetic neuropathy. Because neuropathy causes a loss of sensation, particularly in the feet, the risk of unnoticed small wounds turning into major infections is quite high.

The risk of heart attack and stroke is significantly higher in diabetic patients compared to healthy individuals. Risk groups include not only elderly individuals but also young people struggling with obesity and pregnant women. Gestational diabetes, which develops under the influence of hormones during pregnancy, must be closely monitored for the health of both the mother and the baby. To examine the risks specific to this period in more detail, it is of great importance for expectant mothers to be informed about the symptoms of gestational diabetes and its treatment processes.

When to See a Doctor?

If you are over 45, overweight, have a family history of diabetes, or lead a sedentary lifestyle, you should consult your physician for a diabetes screening once a year, even if you have no complaints. If you experience symptoms such as constant thirst, frequent urination, unexplained fatigue, blurred vision, or numbness in your feet, you should visit a healthcare facility without delay.

Certain situations, however, require emergency medical intervention. Diabetic ketoacidosis (DKA), which occurs with the accumulation of acid in the blood as a result of blood sugar rising to dangerous levels, is a life-threatening condition. If you observe any of the following symptoms in yourself or someone close to you, you should immediately call the 112 Emergency Call Center or go to the nearest emergency room:

• A strong smell similar to rotten apples or acetone on the breath,
• Severe abdominal pain, uncontrollable nausea, and vomiting,
• Difficulty breathing with rapid and deep breaths,
• Confusion, extreme sleepiness, or unresponsiveness to surroundings,
• Severe drying of the skin and sunken-looking eyes due to extreme fluid loss.

Process and Follow-up at BHT CLINIC

The early diagnosis, treatment, and prevention of diabetes complications require expertise and a multidisciplinary approach. In the Endocrinology and Metabolism department at BHT CLINIC İstanbul Tema Hastanesi, personalized treatment plans tailored to each patient's metabolic structure are created. Your diabetes screening tests are concluded quickly and reliably in our advanced technology laboratories.

At our hospital, your organ health is holistically protected by working in collaboration with dietitians, ophthalmologists, and cardiologists not only during the diagnosis stage but also throughout the treatment process. In cases of unexpected blood sugar fluctuations or metabolic crises requiring emergency intervention, our emergency room, providing uninterrupted service 24/7, is by your side with its fully equipped team. When coming for your routine check-ups, having your previous blood test results and a list of the medications you use with you will help your physician evaluate your health history more quickly.

Frequently Asked Questions

Do I need to fast for an HbA1c test?

If only HbA1c is to be measured, you can give blood at any time of the day, even on a full stomach. However, since physicians generally want to see values like fasting blood sugar and cholesterol alongside this test, they usually recommend that you come to the hospital with an 8-10 hour fast.

My HbA1c value is 6.0, what does it mean?

Values between 5.7 and 6.4 percent are considered prediabetes, commonly known as hidden sugar. This result indicates that you are not yet a diabetes patient, but you have a high risk of developing diabetes in the future if you do not make changes to your diet and lifestyle.

Does a home finger-prick blood sugar monitor replace the HbA1c test?

No, it does not. Home devices only measure your blood sugar level at the exact moment you prick your finger. The 3-month blood sugar test, on the other hand, is a much more comprehensive screening test that shows your 90-day average and must be done in a laboratory setting.

How often should the 3-month blood sugar test be done?

For healthy individuals, having it done once a year for screening purposes is generally sufficient. However, for patients diagnosed with diabetes, it is recommended to repeat this test at least two to four times a year to monitor the progress of the treatment and blood sugar control.

Do stress or lack of sleep affect the HbA1c result?

Stress, insomnia the night before the test, or a heavy meal you ate can temporarily raise your blood sugar but will not directly change the HbA1c result. Because this test reflects the long-term average of the last 3 months; it is a reliable indicator unaffected by daily fluctuations.

Keeping your blood sugar levels under control for a healthy future is in your hands. You can book an appointment to have a comprehensive diabetes screening and consult with our specialist physicians.

This article is for informational purposes only; please be sure to consult your physician for diagnosis and treatment.