At what time of day is Insulin-like Growth Factor 1 (IGF-1) typically measured?

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From the Research

IGF-1 levels should be checked in the morning after an overnight fast, preferably between 8 AM and 10 AM, as this timing helps standardize results and minimize the impact of food intake and diurnal variations on IGF-1 levels 1. This recommendation is based on the understanding that IGF-1 levels remain relatively stable throughout the day compared to growth hormone, which fluctuates significantly. Fasting before the test is important as food intake, particularly protein consumption, can temporarily affect IGF-1 levels, as seen in a study where a high protein meal increased IGF-1 levels by 17.5% at 24 hours 1. Some key points to consider when checking IGF-1 levels include:

  • Fasting before the test to minimize the impact of food intake on IGF-1 levels
  • Collecting blood samples in the morning to standardize results and minimize diurnal variations
  • Considering the age-related normal reference range when interpreting IGF-1 levels, especially in children and adults 2
  • Being aware that IGF-1 levels can be influenced by various factors, including growth hormone therapy, nutritional status, and other hormones 3 It's also important to note that IGF-1 levels can be used as a screening test for growth hormone deficiency in children and adults, but should be interpreted in the context of clinical presentation and other diagnostic tests 4, 2.

References

1
Research

Exercise, Dietary Protein, and Combined Effect on IGF-1.

International journal of science and research methodology, 2020

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This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

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