Сывороточный амилоид А (SAA)

Serum amyloid A (SAA), quantitative, is used to assess the presence and intensity of systemic inflammation. Persistent or marked SAA elevation helps estimate the likelihood of secondary AA amyloidosis in the setting of chronic, inadequately controlled inflammatory disease. This acute-phase apolipoprotein is also referred to as amyloid A or amyloid protein A.

Serum amyloid A (SAA) is an acute‑phase protein produced by hepatocytes during inflammatory responses. As an apolipoprotein, SAA can circulate with high‑density lipoproteins and increases in response to tissue injury, infection, or trauma. Its temporal pattern often parallels C‑reactive protein (CRP), and results are commonly interpreted alongside CRP when evaluating inflammatory activity. Circulating SAA serves as the precursor of AA amyloid fibrils; SAA‑derived complexes contribute to amyloid formation and stabilize serum amyloid P (SAP). Sustained elevations represent a key driver of AA amyloidosis, which typically complicates long‑standing, poorly controlled inflammatory disorders. Conditions linked to AA amyloidosis include rheumatoid arthritis, ankylosing spondylitis, familial Mediterranean fever, autoinflammatory syndromes, systemic sclerosis, chronic infections (such as tuberculosis and osteomyelitis), and neoplasms. The kidneys, liver, gastrointestinal tract, and myocardium are frequent targets; proteinuria often predominates early in the clinical course. Higher SAA concentrations are associated with cardiovascular disease risk, may be increased in lung and renal carcinomas, melanoma, and ovarian and endometrial cancers, and correlate positively with body mass index and insulin resistance. Measurement is recommended when evaluating suspected secondary amyloidosis and for monitoring chronic inflammatory activity over time.