Symptoms of hyperinsulinemia that may occur are a result of hypoglycemia. An episode of low glucose (blood sugar) includes symptoms such as:

• Sweating
• Trembling
• Weakness
• Slurred speech
• Confusion
• Dizziness or fainting
• Seizures

When hyperinsulinemia is suspected, blood tests may include fasting insulin and a c-peptide test. Other substances may also be measured, such as cortisol, lactate and arterial blood gases.

Other indicators that may signal hyperinsulinemia include:

• Hypoglycemia when the patient is on an infusion of glucose (blood sugar).
  
  
• Low levels of fatty acids and ketones at the time of hypoglycemia.
  
  
• Rise in glucose levels after glucagon (a hormone that opposes insulin action and stimulates release of glucose from glycogen in the liver) is administered during episodes of hypoglycemia.