Omentin-1 is a newly identified secretory protein, highly and selectively expressed in visceral adipose tissue.Omentin-1 was shown to be the major circulating isoform in human plasma. Lean subjects had significantly higher omentin-1 plasma levels than obese and overweight subjects. Plasma omentin-1 levels were inversely correlated with BMI, waist circumference, leptin levels, and insulin resistance as measured by homeostasis model assessment and positively correlated with adiponectin and HDL levels. In summary, decreased omentin-1 levels are associated with increasing obesity and insulin resistance. The Human Omentin-1 ELISA kit is a sandwich ELISA intended for the determination of Omentin-1 in human serum and plasma. The assay exhibits excellent analytical characteristics and the use of biotin-labelled antibody gives the assay very good sensitivity.