Which two biomarkers are known to rise in inflammation as acute-phase reactants?

Which two biomarkers are known to rise in inflammation as acute-phase reactants?

• A. CRP and D-dimer
• B. CRP and ESR
• C. SAA and ESR
• D. CRP and SAA

Answer: (D)

When inflammation ramps up, the liver releases acute-phase proteins into the bloodstream. The two classic proteins that rise most prominently are C-reactive protein and serum amyloid A. Both are produced in response to inflammatory cytokines, especially IL-6, and they increase rapidly, with CRP climbing within hours and reaching high levels soon after, while SAA follows a similar rapid rise. Clinically, these proteins help signal ongoing inflammation and can participate in immune defense—CRP helps activate complement and opsonize microbes, while SAA has roles in lipid transport and immune cell recruitment. ESR isn’t a liver-produced acute-phase protein itself; it’s a downstream measure that rises due to changes in plasma proteins like fibrinogen affecting red blood cell stacking. D-dimer, on the other hand, reflects coagulation and fibrinolysis, not an acute-phase protein response.

When inflammation ramps up, the liver releases acute-phase proteins into the bloodstream. The two classic proteins that rise most prominently are C-reactive protein and serum amyloid A. Both are produced in response to inflammatory cytokines, especially IL-6, and they increase rapidly, with CRP climbing within hours and reaching high levels soon after, while SAA follows a similar rapid rise. Clinically, these proteins help signal ongoing inflammation and can participate in immune defense—CRP helps activate complement and opsonize microbes, while SAA has roles in lipid transport and immune cell recruitment.

ESR isn’t a liver-produced acute-phase protein itself; it’s a downstream measure that rises due to changes in plasma proteins like fibrinogen affecting red blood cell stacking. D-dimer, on the other hand, reflects coagulation and fibrinolysis, not an acute-phase protein response.