CPT® Code 84305

The CPT® Code 84305 refers to a laboratory test specifically designed to measure the levels of somatomedin, also known as Insulin-Like Growth Factor-1 (IGF1). This test is significant in the field of endocrinology as it provides valuable insights into the growth hormone (hGh) activity within the body. Somatomedin is primarily produced by liver and muscle cells and acts as a crucial growth factor that is stimulated by somatotropin, which is the human growth hormone. The measurement of IGF1 is particularly useful because, unlike somatotropin levels that fluctuate throughout the day, IGF1 levels remain relatively constant, making it a reliable marker for evaluating the production of hGh by the pituitary gland. The clinical implications of somatomedin testing are substantial. Low levels of IGF1 may suggest conditions such as malnutrition, short stature, or delayed puberty, indicating a potential deficiency in growth hormone production. Conversely, elevated levels of IGF1 can be associated with conditions like gigantism, which is characterized by excessive growth due to overproduction of growth hormone. The test is performed by obtaining a blood sample through venipuncture, which is a separately reportable procedure. The serum obtained from the blood sample is then analyzed using a quantitative chemiluminescent immunoassay, a sensitive and specific method for measuring IGF1 levels in the laboratory.