What blood glucose levels indicate hypoglycemia?

Blood Glucose Levels That Indicate Hypoglycemia

Blood glucose levels below 70 mg/dL (<3.9 mmol/L) indicate hypoglycemia, with increasing severity as levels drop further. 1, 2

Classification of Hypoglycemia

According to the American Diabetes Association's standards of care, hypoglycemia is classified into three distinct levels:

• Level 1: Glucose <70 mg/dL (<3.9 mmol/L) but ≥54 mg/dL (≥3.0 mmol/L)
• Level 2: Glucose <54 mg/dL (<3.0 mmol/L)
• Level 3: A severe event characterized by altered mental and/or physical status requiring assistance for treatment of hypoglycemia, regardless of glucose level 1, 2

Clinical Manifestations

Hypoglycemic symptoms typically begin when blood glucose falls below 70 mg/dL and become more pronounced as glucose levels decrease further:

Adrenergic (Autonomic) Symptoms

• Shakiness/tremor
• Sweating
• Tachycardia/palpitations
• Hunger
• Anxiety/nervousness
• Irritability 2

Neuroglycopenic Symptoms

• Confusion/disorientation
• Weakness/fatigue
• Dizziness
• Blurred vision
• Difficulty concentrating
• Slurred speech
• Headache 2

Treatment Approach

Treatment should be initiated promptly when blood glucose falls below 70 mg/dL:

1. For conscious individuals with glucose <70 mg/dL, administer 15-20g of glucose or any carbohydrate containing glucose
2. Recheck blood glucose after 15 minutes
3. Repeat treatment if hypoglycemia persists 1, 2

High-Risk Populations

Certain individuals are at higher risk for hypoglycemia and require closer monitoring:

• Patients with recent (within 3-6 months) Level 2 or 3 hypoglycemia
• Those on intensive insulin therapy
• Individuals with impaired hypoglycemia awareness
• Patients with end-stage kidney disease
• Those with cognitive impairment or dementia
• Elderly patients (≥75 years)
• Patients with food insecurity or low-income status 1, 2

Important Clinical Considerations

• Impaired awareness of hypoglycemia is common in patients with diabetes, especially those with recurrent hypoglycemia, increasing the risk of severe episodes 2
• Continuous glucose monitoring (CGM) is beneficial and recommended for individuals at high risk for hypoglycemia 1
• Glucagon should be prescribed for all individuals taking insulin or at high risk for hypoglycemia 1
• Patients with poorly controlled diabetes may experience hypoglycemic symptoms at higher glucose levels (around 78 mg/dL) compared to non-diabetic individuals (around 53 mg/dL) 3

Pitfalls to Avoid

• Do not rely solely on symptoms for diagnosis, as symptoms can be non-specific and may occur even with normal blood glucose levels 4
• Be aware that hypoglycemia unawareness is common, particularly in patients with recurrent hypoglycemia 2
• Remember that one or more episodes of Level 2 or 3 hypoglycemia should prompt reevaluation of the treatment plan 2
• Consider that 84% of hospitalized patients who experience severe hypoglycemia (BG <40 mg/dL) had a previous episode of hypoglycemia (BG <70 mg/dL), highlighting the importance of early intervention 5