Insulin Laboratory Ranges
Majid Ali, M.D.
The prevailing insulin laboratory ranges in use in the U.S. are inappropriate.
Below are photographs of reports of two U.S. laboratories followed by a table presenting reference ranges for these two laboratories and four additional laboratories that clearly delineate the magnitude of the problem.
- What Is Optimal Insulin Homeostasis?
- This Is the Crucial and Unanswered Question About the Diabetes Type 2 Pandemic.
- What are laboratory criteria for diagnosing hyperinsulinism?
- How can hyperinsulinism be stratified into its mild, moderate, and severe degrees?
- Why are pathologists and other laboratory professionals unable to agree on the above questions.
Examples of Laboratory Reports Showing Inappropriateness of Insulin Ranges
Report One / Full Picture
Report One / Enlarged for Insulin Ranges
Report Two / Full Picture
Note the report comment “Reference ranges not established.”
Report Two / Enlarged
Survey of Laboratory Insulin Ranges
A survey of five major laboratories in the New York City metropolitan area revealed wide variations in the lower and upper limits in the reference ranges for fasting and post-glucose challenge blood insulin concentrations expressed in uIU/mL. Specifically, these values ranged as follows: (1) fasting, zero to 30 uIU/mL; (2) one-hour-post -challenge, zero to 121; (3) two-hour-post-challenge, five to 300; and (3) post- three-hour challenge, three to 150. This survey underscored the need for a new approach for evaluating insulin metabolism.
|Table 1. Upper and Lower Limits of Laboratory Insulin Reference Ranges Table 1. Expressed In uIU/mL Following a Standard Glucose Load From Six Major Clinical Laboratories in the New York Metropolitan Area (as of December 2014)*|
|Laboratory||Fasting||1 Hr||2 Hr||3 Hr|
|Lab 1||1.9 – 23||8 – 112||5 – 35|
|Lab 2||2.6 – 24.9||0.0 – 121.9||0.0 – 163.5||0.0 – 145|
|Lab 3||2.0 – 19.6||6 – 86.0||5 – 55||3 – 20|
|Lab 4||6 – 27||20 – 120||18 – 56||8 – 22|
|Lab 5||00 – 30||30 – 200||40 – 300||50 – 150|
|Lab 6||Does not include insulin ranges in the report. Instead it includes the following note: “Insulin analogues may demonstrate non-linear cross-reactivity in this essay. Interpret results accordingly.**|
* Laboratory: Lab 1, Accurate Diag Lab; Lab 2, Lab Corp; Lab 3, Quest Diagnostics.
**Personal communications with clinicians revealed that they do not find this laboratory note to be satisfactory in their clinical decision-making.