Amyloid A proteins (H2N-Ala-Gly-Leu-Pro-Glu-Lys-Tyr-OH) are a family of apolipoproteins associated with high-density lipoprotein in plasma. Different isoforms of SAA are expressed constitutively at different levels or in response to inflammatory stimuli. Serum amyloid A (SAA) is also an acute-phase marker that responds rapidly. Like CRP, levels of acute-phase SAA increase within hours after an inflammatory stimulus, but the magnitude of the increase may be greater than that of CRP. Relatively trivial inflammatory stimuli can lead to SAA responses. It has been suggested that SAA levels correlate better with disease activity in early inflammatory joint disease than do ESR and CRP levels. Although SAA is largely produced by hepatocytes, more recent studies show that SAA is also produced by adipocytes and that its serum concentration is associated with body mass index [3].