Limited preanalytical requirements for insulin measurement

Area of Science:

• Clinical Chemistry
• Endocrinology
• Laboratory Medicine

Background:

• Accurate insulin measurement is crucial for diagnosing and managing metabolic disorders.
• Sample stability during transport from clinics to labs impacts test reliability.
• Current protocols often require immediate processing or freezing, posing logistical challenges.

Purpose of the Study:

• To assess the stability of insulin in serum and plasma samples during transport.
• To determine optimal storage conditions for maintaining insulin integrity.
• To evaluate the influence of anticoagulants like EDTA and sodium fluoride on insulin stability.

Main Methods:

• Blood samples were collected from 15 volunteers.
• Samples were stored at room temperature for 24 hours, with and without additives (EDTA, sodium fluoride).
• Insulin concentrations were measured and compared between different storage and additive conditions.

Main Results:

• Insulin demonstrated stability in EDTA-containing tubes at room temperature for at least 24 hours.
• Significantly lower insulin concentrations were observed in samples without additives or with potassium fluoride.
• EDTA effectively preserved insulin integrity during simulated transport conditions.

Conclusions:

• Insulin measurements are reliable when samples are transported within 24 hours at room temperature in EDTA tubes.
• Centrifugation and freezing of plasma are unnecessary if samples are processed within 24 hours.
• These findings support broader implementation of insulin testing for assessing insulin sensitivity.