Estimation of serum amyloid A protein in neonatal sepsis: a prospective study

Abstract

Background: The diagnosis of neonatal sepsis continues to remain a challenge owing to nonspecific early clinical signs and the nonavailability of a reliable biomarker. The result of blood culture, gold standard test for diagnosis, is available only after 72 h of sampling. Other tests include C-reactive protein (CRP), tumor necrosis factor-α, procalcitonin, serum amyloid A (SAA), and other acute-phase reactants having contradictory outcomes. Objective: To determine the levels of SAA protein in neonatal sepsis, to correlate SAA levels with CRP, and to evaluate the role of SAA as a marker of neonatal sepsis. Materials and Methods: This prospective cohort study was done in the neonatal intensive care unit, including 90 neonates ≥28 weeks gestational age with clinical signs and symptoms of sepsis. Serum sample was collected at the onset of clinical signs and symptoms of sepsis before the start of antibiotic therapy. CRP was estimated by immunoturbidimetric method, and SAA was estimated by ELISA method. Result: On the basis of blood culture report, the study subjects were grouped into culture-positive (n = 40) and culture-negative (n = 50) groups. Mean SAA values were significantly higher in culture-positive group (47.43 ± 23.39 μg/mL) when compared with the culture-negative group (p < 0.001). Statistically significant positive correlation was seen between SAA and CRP values (r = 0.775, p < 0.00001). Using a cut-off of ≥10 μg/mL, SAA showed a sensitivity, specificity, positive predictive value, and negative predictive value of 95%, 82%, 81%, 95%, respectively, when compared with CRP, which gave values of 92.5%, 10%, 45.12%, and 62.5%, respectively. Conclusion: The results of this study support the use of SAA in the diagnosis of neonatal sepsis.