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.


FiveQuestions

  • 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.

 

 

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