I have a 17-year-old female patient with an IGF-1 of 418ng/ml. The standard range on the Quest blood test result is 185-551ng/ml.
Like most hormones, IGF-1 shows a large variance in ranges based on age (see table below). As we know from studying hormones, the younger patient tends to output hormones at a higher level than their aging adult counterparts, which is why your 17-year-old patient has much higher ranges than the ranges used in ODX.
Given that the ODX application is set to work for adult patients in their 20s and above, we set standard ranges for hormones to be a reflection of ranges for people in their 20s and 30s and adjust the optimal range accordingly to provide a window into potential trends towards dysfunction when the result strays above or below the optimal but still within the standard range.
Here are the standard ranges from QUEST by age:
Adult (ng/mL)
18-19.9 Years 108-548
20-24.9 Years 83-456
25-29.9 Years 63-373
30-39.9 Years 53-331
40-49.9 Years 52-328
50-59.9 Years 50-317
60-69.9 Years 41-279
70-79.9 Years 34-245
>80 Years 34-246
Given this, we have chosen the standard range to be set at 53 - 373 ng/ml, which encompasses the low range for someone in their 30s and the high range for someone in their late 20s. We have set the optimal range to be 60 - 201 ng/ml because there is convincing research showing that levels of IGF-1 above and below the optimal range, which may still be in the standard range, show a trend towards the development of dysfunction:
Above optimal: A trend towards insulin resistance, obesity, evidence of a diet high in refined carbohydrates
Below optimal: Inflammation, GH insufficiency, a finding in the development of dementia and Alzheimer's disease, lipid abnormalities, metabolic syndrome, fatigue, and reduced tolerance for exercise.
It's important to point out that the optimal ranges are not diagnostic but can be used to guide us to a better sense of a trend towards or away from dysfunction in the body and metabolic systems