Hemoglobin A1c 13.7 %: Is That High?

Is Hemoglobin A1c 13.7 % Low, Normal, or High?

HbA1c 13.7% is considered very high and indicates that blood sugar has been severely elevated over the past two to three months. The American Diabetes Association defines diabetes at HbA1c of 6.5 percent or above, and at 13.7% your blood sugar has been far above target for an extended period. This result requires urgent medical attention. While this number is serious, it is important to know that with proper treatment and support, significant improvement is possible.

An A1c of 13.7% unequivocally signals severely uncontrolled diabetes, significantly exceeding the normal reference range of 4.0-5.6%. This level indicates dangerously high blood glucose levels sustained over a prolonged period, representing a critical situation that demands immediate and aggressive intervention to avert acute crises like diabetic ketoacidosis and mitigate long-term organ damage. At this extreme elevation, the most probable causes include a new, previously undetected diagnosis of either type 1 or type 2 diabetes, or a severe breakdown in current diabetes management—often due to significant medication non-adherence, rapid progression of insulin resistance, or an inadequate treatment regimen. Immediate clinical follow-up will typically involve a comprehensive review of existing medications and lifestyle, alongside additional blood tests such as C-peptide and autoantibody screening to help differentiate diabetes types if not yet established. Urgent referrals to an endocrinologist and a certified diabetes educator are standard, coupled with intensified home blood glucose monitoring. While daunting, patients should understand that this high A1c, though serious, provides a clear and measurable starting point for significant improvement; with consistent effort and expert medical guidance, substantial reductions are achievable within 3-6 months, leading to a noticeable decrease in immediate symptoms and a crucial reduction in long-term complication risks.

Hidden Risk of Hemoglobin A1c 13.7 %

An HbA1c of 13.7% puts your body under significant stress, even if you have adapted to how it feels. At this level, blood sugar has been running so high for so long that serious complications are either developing or accelerating. The urgency is real, even if you do not feel dramatic symptoms.

A Hemoglobin A1c of 13.7% signifies sustained high blood glucose levels, significantly increasing the risk of microvascular complications. At this level, advanced glycation end products (AGEs) accumulate, damaging the delicate blood vessels in the eyes, kidneys, and nerves. This can manifest as proliferative retinopathy, leading to vision loss, or diabetic nephropathy, potentially progressing to kidney failure requiring dialysis. Nerve damage, or neuropathy, is also highly probable, presenting as painful sensations, numbness, or even foot ulcers that are slow to heal due to impaired circulation and immune function, posing a risk of amputation. The prolonged hyperglycemia also fuels systemic inflammation, contributing to cardiovascular disease.

• At this HbA1c level, your estimated average blood sugar has been approximately 298 mg/dL, nearly three times the normal average
• The risk of diabetic retinopathy (eye damage) increases exponentially above HbA1c 8.0%. At 13.7%, annual eye exams are critical
• Kidney damage is a major concern. The National Kidney Foundation reports that sustained high blood sugar is the leading cause of kidney failure
• Nerve damage (neuropathy) progresses rapidly at this HbA1c level, potentially causing permanent numbness, pain, or weakness in the extremities
• Cardiovascular risk is severely elevated. People with poorly controlled diabetes face dramatically higher rates of heart attack and stroke
• Wound healing is impaired and infection risk is increased, making even minor cuts and injuries a greater concern

What Does a Hemoglobin A1c Level of 13.7 % Mean?

HbA1c measures how much glucose has bonded to the hemoglobin in your red blood cells. Since red blood cells live about three months, HbA1c captures a rolling average of your blood sugar over that period. It is one of the most important tests for managing diabetes.

Achieving a Hemoglobin A1c of 13.7% strongly suggests a profound mismatch between insulin availability and the body's demand, most likely due to insufficient or ineffective diabetes medication combined with significant dietary indiscretions. This could involve consistent consumption of high-glycemic carbohydrates without adequate coverage from prescribed insulin or oral hypoglycemic agents, or perhaps an unmanaged period of increased stress or illness that has chronically elevated blood sugar. Non-adherence to a prescribed medication regimen, whether due to forgetfulness, side effects, or cost, is also a primary contributor to such elevated readings. Underlying issues like inadequate insulin production or severe insulin resistance that have progressed significantly are also highly plausible.

At 13.7%, your estimated average blood sugar has been approximately 298 mg/dL. Normal average blood sugar is around 100 mg/dL, and the ADA target for most people with diabetes is an HbA1c below 7.0 percent, which corresponds to roughly 154 mg/dL. Your reading indicates that blood sugar has been running about three times higher than normal.

This level of glucose elevation means that your body's insulin system is severely impaired. In type 2 diabetes, this usually means a combination of advanced insulin resistance and declining insulin production from the pancreas. In type 1 diabetes, it indicates that insulin therapy needs significant adjustment.

At 13.7%, excess glucose is constantly circulating in your blood, bathing your blood vessels, nerves, and organs in sugar. This creates a toxic environment that accelerates damage throughout the body. The longer blood sugar stays at this level, the more harm accumulates. However, bringing HbA1c down even partially provides immediate protective benefit. Reducing from 12.0 to 9.0 percent, while still above target, dramatically reduces complication risk.

Lifestyle Changes for Hemoglobin A1c 13.7 %

Lifestyle changes at HbA1c 13.7% are important but should happen alongside medical treatment, not instead of it. At this level, lifestyle alone cannot bring blood sugar to a safe range. However, the habits you build now will determine how well your treatment works and how quickly your numbers come down.

Immediate medical intervention is critical with a Hemoglobin A1c of 13.7%. Schedule a prompt appointment with your endocrinologist or primary care physician to discuss immediate medication adjustments, which may include initiating or increasing insulin therapy. Simultaneously, undertake a rigorous self-monitoring of blood glucose, checking levels at least four times daily, and meticulously track all food intake, paying close attention to carbohydrate portions. A consultation with a registered dietitian is paramount to develop a personalized, low-glycemic diet plan and to implement substantial lifestyle changes such as increasing daily physical activity to at least 30 minutes of moderate-intensity exercise. Retest your A1c in 90 days.

Physical activity is one of the fastest ways to help lower blood sugar. Exercise moves glucose from the blood into muscles, and this effect lasts for hours. The ADA recommends 150 minutes per week of moderate activity. Walking after meals is a great starting point because it directly addresses the blood sugar spike that follows eating. Even 10 to 15 minutes of walking after each meal can make a noticeable difference in glucose readings.

Weight loss, if applicable, has a powerful impact on insulin resistance. Every pound lost improves insulin sensitivity. A target of 5 to 10 percent body weight loss is realistic and meaningful. Focus on sustainable changes rather than extreme diets.

If you smoke, stopping is essential. Smoking worsens every diabetes complication and increases insulin resistance. Your doctor can help with cessation support.

Sleep and stress both affect blood sugar significantly. Aim for seven to nine hours of sleep per night. Chronic stress raises cortisol, which raises blood sugar. Building even simple stress management practices into your day supports your treatment plan.

Written by

Ernestas K.

Clinical research writer specializing in human health, biology, and preventive medicine.

Reviewed against ADA, CDC, NIH, WHO, Mayo Clinic guidelines · Last reviewed March 20, 2026