Serum amyloid A (SAA) protein and high-sensitivity C-reactive protein (hsCRP) in healthy newborn infants and healthy young through elderly adults.

Aim: To determine the levels of serum amyloid A (SAA) protein and high-sensitivity C-reactive protein (hsCRP) in different age groups.

Methods: Serum samples from 70 healthy newborn infants, 80 blood donors and 81 healthy elderly individuals were analysed using a nephelometric method. The 231 samples were grouped as follows: 35 umbilical cords, 35 newborns, 48 young adults, 28 middle-aged adults, and 85 elderly adults.

Results: Serum levels of both SAA and hsCRP were lower in umbilical cords than in the newborns and young, middle-aged and elderly adults (p<0.0001). The SAA and hsCRP levels were comparable in newborns, and young and middle-age adults, but higher in elderly adults (p<0.0001-0.03). SAA (r2=0.159, p<0.0001) and hsCRP (r2=0.059, p<0.0001) were positively correlated with age and to each other (r2=0.385, p<0.0001).

Conclusion: Serum levels of SAA and hsCRP in umbilical cord blood are close to the detection limit and lower than in the other age groups investigated. The elderly have generally higher levels than the younger age groups, which require higher decision levels in inflammatory diseases, including infections. In newborns and young and middle-aged adults, the lower decision levels of 10 mg/l for SAA and 5 mg/l for CRP are suggested.