Leptin is a hormone that helps regulate appetite by signaling hunger satisfaction (satiety). This test measures the amount of leptin in the blood to detect a deficiency that may be contributing to obesity.
The level of leptin is related to the adipose (fat) tissue of body.
In the obese, decreased leptin levels may indicate some degree of deficiency, while increased concentrations are thought to be associated with resistance to the effects of leptin. Most obese people will have increased levels, but about 10% may have some degree of leptin deficiency.
Very rarely, significantly decreased leptin levels may indicate an inherited leptin deficiency linked to severe obesity.
Leptin secretion follows a circadian pattern, meaning that the concentration in blood will vary throughout a 24-hour time period (higher at night than during the day).