Serum leptin

Method

Circulating leptin concentration in serum or plasma by immunoassay (ELISA or radioimmunoassay). Species, fasting state and clock time of sampling are recorded on the edge; leptin has a marked diurnal rhythm and rodent and human values are not comparable.

The method is part of the endpoint identity. Studies measuring the same quantity by a different method are held as separate endpoints.

Notes

CRITICAL SIGN INVERSION against serum adiponectin, the other adipokine measured by immunoassay in the same serum aliquot, in the same meta-analysis, usually in adjacent rows: this improves by FALLING (SMD -1.33) and adiponectin by RISING (SMD +1.04). A single adipokine node would cancel the two to nothing. Distinct also from CAT:outcome/fat-mass and body fat percentage, with which it correlates tightly but which are body-composition measurements in kilograms or percent rather than a hormone concentration - and this falls acutely with energy restriction days before any fat mass change is measurable.