Cleveland Heartlab I, Metabolic, Test

CPT Code: 83525

Order Code:
ABN Requirement:  No
Synonyms: Immunoreactive Insulin
Specimen: Serum
Volume: 1.0 mL
Minimum Volume: 0.5 mL
Container: Gel-barrier tube (SST, Tiger Top)


  1. Collect and label sample according to standard protocols.
  2. Gently invert tube 5 times immediately after draw. Do not shake.
  3. Allow blood to clot 30 minutes.
  4. Centrifuge for 10 minutes.

Patient Preparation: Overnight fasting is required.

Transport: Store serum at 2°C to 8°C after collection and ship the same day per packaging instructions included with the provided shipping box.


Ambient (15-25°C): 24 hours
Refrigerated (2-8°C): 7 days
Frozen (-20°C): 28 days

Causes for Rejection: Specimens other than serum; improper labeling; samples not stored properly; samples older than stability limits; hemolysis; gross icterus

Methodology: Immunoassay (IA)

Turn Around Time: 1 to 3 days

Risk Ranges:

Low Risk
Moderate Risk
High Risk

Adult cardiovascular event risk category cut points (optimal, moderate, high) are based on Insulin Reference Interval studies performed at Quest Diagnostics in 2022.

Clinical Significance: Insulin is useful in diagnosing hyperinsulinemia in hypoglycemic patients. Hyperinsulinemia may be due to an insulin-producing tumor (insulinoma), syndrome of insulin resistance, or persistent hyperinsulinemic hypoglycemia of infancy.

Limitations: Patients who have been regularly exposed to animals or have received immunotherapy or diagnostic procedures utilizing immunoglobulins or immunoglobulin fragments may produce antibodies, e.g. HAMA, that interfere with immunoassays. Additionally, other heterophile antibodies such as human anti-goat antibodies may be present in patient samples. Such interfering antibodies may cause erroneous results. Patients on insulin therapy are prone to the development of anti-insulin antibodies. These antibodies may interfere with the assay.

The CPT codes provided are based on AMA guidelines and are for informational purposes only. CPT coding is the sole responsibility of the billing party. Please direct any questions regarding coding to the payer being billed.