Eagle Biosciences Functional Leptin ELISA Assay Kit was utilized in a clinical study to monitor those with functional leptin deficiency. Circulating leptin levels in the body are crucial for maintaining body weight. This clinical study was developed to test for a valid diagnostic tool to detect functionally leptin in those who have defective leptin receptor binding. To view more information about our Leptin ELISA Assay Kit click here.


Context and aims: Functional leptin deficiency is characterized by high levels of circulating immunoreactive leptin (irLep), but a reduced bioactivity of the hormone due to defective receptor binding. As a result of the fact that affected patients can be successfully treated with metreleptin, it was aimed to develop and validate a diagnostic tool to detect functional leptin deficiency.

Methods: An immunoassay capable of recognizing the functionally relevant receptor-binding complex with leptin was developed (bioLep). The analytical quality of bioLep was validated and compared to a conventional assay for immune-reactive leptin (irLep). Its clinical relevance was evaluated in a cohort of lean and obese children and adults as well as in children diagnosed with functional leptin deficiency and their parents.

Results: In the clinical cohort, a bioLep/irLep ratio of 1.07 (range: 0.80–1.41) was observed. Serum of patients with non-functional leptin due to homozygous amino acid exchanges (D100Y or N103K) revealed high irLep but non-detectable bioLep levels. Upon treatment of these patients with metreleptin, irLep levels decreased, whereas levels of bioLep increased continuously. In patient relatives with heterozygous amino acid exchanges, a bioLep/irLep ratio of 0.52 (range: 0.48–0.55) being distinct from normal was observed.

Conclusions: The new bioLep assay is able to diagnose impaired leptin bioactivity in severely obese patients with a homozygous gene defect and in heterozygous carriers of such mutations. The assay serves as a diagnostic tool to monitor leptin bioactivity during treatment of these patients.

Wabitsch, M., Pridzun, L., Ranke, M., Schnurbein, J. V., Moss, A., Brandt, S., . . . Kratzsch, J. (2017). Measurement of immunofunctional leptin to detect and monitor patients with functional leptin deficiency. European Journal of Endocrinology,176(3), 315-322. doi:10.1530/eje-16-0821