Nicotinamide phosphoribosyltransferase (Nampt) is the rate-limiting enzyme in the salvage pathway for the biosynthesis of nicotinamide adenine dinucleotide (NAD+) from nicotinamide. Nampt was first described as a pre-B-cell colony enhancing factor (PBEF). It was later named visfatin, as it was found to be highly enriched in visceral fat, with plasma levels increasing with obesity. Whether it is called Nampt, PBEF, or visfatin, this protein has important roles, both intra- and extracellularly, in cellular metabolism and disease. Extracellularly, the levels of Nampt in serum correlate with body mass index and body fat mass, are increased during inflammation, and are decreased with liver cirrhosis. Extracellular Nampt regulates insulin secretion in (beta) cells by regulating systemic NAD+ biosynthesis. Nampt levels and expression in serum, circulating leukocytes, and tissues may be useful biomarkers for inflammation, cancer, obesity, and other diseases. Cayman's Nampt/Visfatin (human) EIA Kit is an immunometric assay which can be used to measure Nampt/Visfatin in human serum. The assay exhibits a detection limit of 30 pg/ml and an assay range of 0-8 ng/ml.