Understanding Lab Tests for Hypoglycemia
Written by Private MD Labs Medical Writing Team • Last Updated: September 8, 2025
Hypoglycemia occurs when blood glucose levels drop below normal ranges, typically under 70 mg/dL. While symptoms like shakiness, sweating, confusion, and rapid heartbeat can suggest low blood sugar, accurate diagnosis and identification of the underlying cause requires specific blood testing.
Top Recommended Test
Glucose, Serum
This is the primary test for confirming hypoglycemia by directly measuring blood glucose levels. Low serum glucose levels below normal ranges confirm the diagnosis and can help identify if the condition is related to medication use in diabetic individuals or other health issues such as liver disease, certain tumors, or hormone deficiencies.
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Why Blood Testing is Essential for Hypoglycemia
Blood tests are fundamental for confirming hypoglycemia and determining its cause. Since hypoglycemia can result from various factors including medication effects, hormone imbalances, or underlying conditions, comprehensive testing helps healthcare providers develop appropriate treatment strategies.
Other Relevant Tests
Insulin, Fasting
This test measures insulin levels during fasting to help identify if hypoglycemia is caused by excess insulin in the blood. High insulin levels during hypoglycemic episodes can indicate conditions such as insulinoma or inappropriate insulin dosing in diabetic patients.
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C-Peptide, Serum
C-peptide testing helps determine if hypoglycemia is due to overproduction of insulin by the body. High C-peptide levels during hypoglycemic episodes can indicate endogenous insulin overproduction, which is important for distinguishing between different causes of hypoglycemia.
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Insulin, Free (Bioactive)
This test specifically measures the bioactive form of insulin that is immediately available to affect blood glucose. High levels of free bioactive insulin can indicate excess insulin production as the cause of hypoglycemia, providing more specific information about insulin-related hypoglycemia.
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Hemoglobin (Hgb) A1c With eAG Estimation
This test provides information about average blood glucose levels over the past 2-3 months through estimated average glucose (eAG). Low eAG levels may indicate frequent episodes of hypoglycemia, helping to assess the pattern and severity of blood sugar control issues.
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IGF-2
IGF-2 testing is important when evaluating non-islet cell tumor hypoglycemia (NICTH), a rare condition where tumors produce excess IGF-2. This test helps identify if hypoglycemia is caused by tumor-related IGF-2 overproduction, which requires different treatment approaches.
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Kidney Function Profile
Kidney function assessment is valuable because impaired kidney function can affect glucose metabolism and insulin clearance. This comprehensive profile helps identify if kidney dysfunction is contributing to hypoglycemic episodes, particularly in diabetic individuals who may have taken excess insulin or have inadequate food intake.
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Understanding Your Test Results
Interpreting hypoglycemia test results requires medical expertise, as the combination of glucose, insulin, C-peptide, and other hormone levels helps determine the specific cause. Your healthcare provider will evaluate these results together with your symptoms and medical history to develop an appropriate treatment plan.
Important Considerations
The information here is for educational purposes only and is not a substitute for professional medical advice. Hypoglycemia can be a serious condition requiring immediate medical attention. Always consult with a healthcare provider for proper diagnosis, treatment, and ongoing management.
