Fig. 5

Figure 5 shows the overnight growth hormone (GH) test. Blood sample is collected every 20 min for GH and the physiological surge in GH is profiled. GH levels during waking hours are normally low. During sleep, there are usually several pulses of GH >20 mU/L (7.7 μg/L), usually associated with slow wave sleep. A peak GH response <10 mU/L (3.9 μg/L) suggests GH deficiency; a response of 10–20 mU/L (3.9–7.7 μg/L) may suggest partial GH deficiency; a response >20 mU/L (>7.7 μg/L) is regarded as normal.(1 mU/L × 0.385 = 1 μg/L)