To determine if you have a leptin deficiency that is contributing to obesity; to identify increased leptin; on a research basis to help understand leptin's roles in the body and its ties to obesity
Leptin
Leptin
This article was last reviewed
on
This article waslast modified
on
May 25, 2018.
At a Glance
Why Get Tested?
When To Get Tested?
When a child has severe obesity that may be due to a very rare inherited leptin deficiency; sometimes to help evaluate obesity; when participating in a research study
Sample Required?
A blood sample drawn from a vein in your arm
Test Preparation Needed?
None
Accordion Title
Common Questions
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How is it used?
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.
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When is it ordered?
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 below.)
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).
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What does the test result mean?
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).
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Is there anything else I should know?
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
- Role in fertility
- Association with depression, stress, and anxiety
- Role in maintaining glucose levels and its interaction with insulin
- Association between leptin levels, weight loss, and hunger
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Should everyone who is overweight have a leptin test performed?
Leptin testing is not routinely performed and is not indicated for most people. If someone is obese and has persistent hunger, or has a young child who is severely obese, then leptin testing may be considered.
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How are classifications of body weight determined?
Classification is currently based on body mass index, or BMI.
For youth, weight and height as well as age and sex are considered in determining their BMI percentile. An overweight youth is one whose BMI is between the 85th percentile and the 94th percentile on standardized growth charts. An obese youth is one who is at or above the 95th percentile on standardized growth charts or has a BMI of greater than or equal to 30 kg/m2, whichever is lower.
For adults, BMI is calculated as:
BMI = (Weight in pounds) / (height in inches squared) x 703
BMI Classification
Less than 18.5 Underweight
18.5 – 24.9 Normal weight
25.0 – 29.9 Overweight
30 and above Obese
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Can leptin testing be performed in my doctor's office?
No. Leptin testing is not performed in doctors' offices and is not offered by most laboratories. The test will probably need to be sent to a reference laboratory.
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What can I do to lower or increase leptin levels?
Leptin levels will often decrease when an obese person loses weight and increase when a person becomes obese, but they do not otherwise respond to lifestyle changes.
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How is leptin deficiency treated?
In those with very rare inherited leptin deficiencies, replacement therapy has been successful in addressing obesity. However, there are insufficient data at this time to support its routine use for other leptin deficiencies.
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Are there other adipokines besides leptin?
Although leptin was the first adipocyte cytokine (or "adipokine") identified, many others have been discovered. The two that have been most extensively investigated are resistin, which increases insulin resistance, and adiponectin, which lowers it. Resistin is increased and adiponectin is decreased in obesity. They also have opposite effects on inflammation; resistin increases inflammation, while adiponectin decreases it. Another recently discovered adipokine is visfatin, which is elevated in type 2 diabetes and may play a role in elevating insulin levels. Several other adipokines are aplin, chemerin, and omentin, all of which appear to be anti-inflammatory.