The leptin test is not ordered routinely and its usefulness in medical settings is yet to be fully established. Most testing is still performed in a research setting as the role of leptin is further investigated.
In clinical settings, the leptin test is most likely to be ordered on an obese child, especially if there is a family history of early-onset obesity. It may sometimes be ordered on an obese person who has symptoms of frequent, persistent hunger to detect a leptin deficiency or excess.
On occasion, the test may be used along with other tests, such as a lipid profile, thyroid panel, glucose, insulin, and/or A1c, to evaluate the health status of an obese person and to detect underlying conditions that may be contributing to or complicating their condition.
Leptin is primarily ordered during clinical studies, when it is performed to further investigate the role of leptin.
Leptin testing is not frequently ordered outside of a research setting, but it may sometimes be ordered when a child has been classified as obese, especially when there is a family history of early-onset obesity. (For classifications, see Common Questions #2.)
Some doctors may order a leptin test when evaluating an obese person to determine whether they may have a leptin deficiency or an excess (to detect leptin resistance).
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).
Women normally have higher leptin levels than men. Leptin concentrations are also increased during pregnancy and may be significantly increased in women with gestational diabetes or pre-eclampsia. The test is not, however, used to monitor these conditions.
The usefulness of leptin results in a medical setting, especially in evaluating excess or and deficient amounts of the hormone, is yet to be fully established. For instance, someone with a rare inherited deficiency may benefit from leptin replacement therapy, but there is not yet sufficient data to determine whether or not a person with a mild deficiency would also benefit from a targeted treatment.
Some of the other topics that have been or are being studied in association with leptin include its:
Contribution to inflammation and atherosclerosis or, conversely, its protection from atherosclerosis
Increase with gestational diabetes and with pre-eclampsia during pregnancy
This article was last reviewed on April 19, 2013. | This article was last modified on February 26, 2016.
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