The IGF-1 test is used to evaluate growth disorders and pituitary function. Low IGF-1 levels can indicate growth hormone deficiency, leading to symptoms such as short stature or delayed development. Elevated IGF-1 levels can be associated with excessive growth hormone production, causing symptoms like enlarged hands and feet or excessive growth in children (gigantism). The test is essential for diagnosing and managing conditions related to growth hormone imbalances and pituitary disorders.