Overview: Insulin Sensitivity TestIntroduction: The Insulin Sensitivity Test assesses insulin sensitivity to diagnose diabetes or metabolic syndrome, helping guide treatment for blood sugar control. Affecting 1 in 5 people with obesity, insulin resistance poses diagnostic challenges due to subtle onset. Following 2023 American Diabetes Association (ADA) guidelines, it uses immunoassay for high accuracy, supporting endocrinology screening. This test is vital for diagnosis, intervention planning, and improving outcomes in endocrinology.
Other Names: Insulin Sensitivity Assay, Diabetes Risk Test.
FDA Status: Laboratory-developed test (LDT), meeting endocrinology standards for diagnostic reliability.
Historical Milestone: Insulin sensitivity testing began in the 1970s with research by Reaven, who linked it to metabolic syndrome. Immunoassay advancements in the 1990s by Roche improved detection, surpassing earlier clamp methods.
Purpose: Assesses insulin sensitivity index to diagnose diabetes or metabolic syndrome, guides lifestyle or medication therapy, and evaluates patients with high blood sugar, aiming to prevent complications.
Test Parameters: Insulin sensitivity index
Pretest Condition: Fasting required to reflect baseline levels. Collect serum or plasma. Report history of diabetes or obesity.
Specimen: Serum (SST, 2-5 mL), Plasma (EDTA, 2-4 mL); 2 mL serum in SST. Transport in a biohazard container.
Sample Stability at Room Temperature: 6 hours
Sample Stability at Refrigeration: 1 week
Sample Stability at Frozen: 1 month
Medical History: Document high blood sugar or obesity. Include current medications or diet.
Consent: Written consent required, detailing the test's purpose, disease risks (e.g., cardiovascular disease), and sample collection risks.
Procedural Considerations: Uses immunoassay to measure sensitivity, requiring labs with analyzers. Results available in 1-2 days. Performed in labs with strict handling.
Factors Affecting Result Accuracy: Non-fasting status or sample hemolysis can affect results. Medications may alter levels, requiring correlation.
Clinical Significance: Low sensitivity confirms insulin resistance, guiding therapy. Early intervention might prevent progression, while untreated cases lead to diabetes. Normal levels may require glucose tolerance test.
Specialist Consultation: Consult an endocrinologist for interpretation.
Additional Supporting Tests: HOMA-IR, HbA1c, or lipid profile to confirm diagnosis.
Test Limitations: Indirect measure; correlation with clinical status needed. False results possible with beta-cell dysfunction.
References: ADA Guidelines, 2023; Diabetes, Reaven GM, 2022.
