A standardised score of IGF-1 relative to your age and sex.
IGF-1 SD, or IGF-1 standard deviation score (SDS), is a calculated value derived from your IGF-1 result, not a separate blood test. It expresses how far your IGF-1 sits from the average for your age and sex, measured in standard deviations.
The formula compares your measured IGF-1 with the mean for your age and sex, divided by the standard deviation of that reference group: SDS = (your IGF-1 − age and sex mean) ÷ standard deviation.
IGF-1, insulin-like growth factor 1, is made mainly in the liver under the control of growth hormone, and it naturally changes a great deal with age and sex. Because a raw IGF-1 value is hard to interpret on its own, converting it to a standard deviation score shows where you sit relative to people of the same age and sex.
A high SDS means your IGF-1 is well above average for your age and sex, which can be seen with growth hormone excess. A low SDS means it is well below average, which can reflect growth hormone deficiency, poor nutrition or liver disease.
Aniva reads your result against research-backed ranges, not just the lab's wide normal. The reference shown below is specific to this biomarker.
An SDS of 0 is exactly average for your age and sex. Most healthy people fall roughly between -2 and +2 SDS. Values below -2 or above +2 are flagged as unusually low or high and prompt further assessment. The reference population and assay must match, so interpret against the reporting lab with a clinician.
The SDS depends on the reference data and assay used, so scores are not directly comparable between different labs. IGF-1 is lowered by malnutrition, liver disease, poorly controlled diabetes and hypothyroidism, and is affected by oestrogen therapy, all of which shift the score independently of growth hormone status.
Read with its component, IGF-1 itself, and alongside growth hormone testing where indicated, plus IGFBP-3 in some assessments.
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