GH deficiency is diagnosed by –
**Core Concept**
GH (Growth Hormone) deficiency is a condition characterized by inadequate production of growth hormone, leading to various growth and developmental abnormalities. It can result from pituitary gland tumors, radiation therapy, or genetic mutations affecting the GH gene. GH plays a crucial role in regulating growth, body composition, and metabolism.
**Why the Correct Answer is Right**
GH deficiency is typically diagnosed using a 24-hour GH profile, which measures the levels of GH in the blood throughout the day. This test is considered the gold standard for diagnosing GH deficiency. The profile helps identify the characteristic dips in GH levels, which are often absent or blunted in individuals with GH deficiency. The 24-hour GH profile takes into account the pulsatile secretion of GH, providing a more accurate assessment of GH production.
**Why Each Wrong Option is Incorrect**
**Option A:** Random GH level measurement is incorrect because it does not account for the pulsatile nature of GH secretion, which can lead to false-negative results.
**Option B:** Insulin-like growth factor-1 (IGF-1) levels alone are not sufficient for diagnosing GH deficiency, as IGF-1 levels can be influenced by various factors, including nutrition and liver function.
**Option C:** Cortisol stimulation test is not relevant to diagnosing GH deficiency, as it is primarily used to assess adrenal function.
**Clinical Pearl / High-Yield Fact**
It's essential to remember that a single GH measurement is not sufficient for diagnosing GH deficiency, and a 24-hour GH profile is often required to confirm the diagnosis.
**Correct Answer: C. Cortisol stimulation test is not relevant to diagnosing GH deficiency, as it is primarily used to assess adrenal function.