LEP and lipodystrophy: Additionally, to use these symptoms (and loss of subcutaneous fat) to diagnose lipodystrophy, decreased leptin levels can be used as a differential diagnostic test, in which very low fasting serum adiponectin and leptin levels indicate a diagnosis of GLD instead of PLD and correlate with hypertriglyceridemia, high insulin levels (or insulin-resistant diabetes) and low high-density lipoprotein C [10].