Serum Amyloid to Diagnose Sepsis

Serum Amyloid to Diagnose Sepsis

Arnon S, Litmanovitz I, Regev RH, et al. Serum amyloid A: an early and accurate marker of neonatal early-onset sepsis. J Perinatol 27: 297-302. Full Text | PDF

Objectives: To evaluate the accuracy of serum amyloid A (SAA), an acute phase protein in the detection of neonatal early-onset sepsis, by means of a fast automated SAA kit.

Study Design: Full-term infants <72 h of age, who had risk factors and/or were suspected of having sepsis, were eligible for study. The levels of SAA were taken at 0, 24 and 48 h post sepsis evaluation. Thirty matched infants served as a control group for comparing SAA concentrations.

Results: Of 104 infants eligible for entry to the study, 23 had sepsis and 81 had not sepsis. The SAA levels of the septic group were significantly higher than those of the nonseptic group at 0, 24 and 48 h (P<0.01 for all time points). In comparison with C-reactive protein (CRP), SAA levels rose earlier and in a sharper manner, had higher levels and returned faster to normal values in infants with early onset sepsis. At 0 h post-sepsis evaluation, serum SAA had an overall better diagnostic accuracy for predicting early onset sepsis than CRP (sensitivity (96 vs 30%), specificity (95 vs 98%), positive predictive value (85 vs 78%), negative predictive value (99 vs 83%), positive likelihood ratio (19 vs 12), and negative likelihood ratio (0.05 vs 0.71).

Conclusion: SAA is advocated as an inflammatory marker of neonatal early-onset sepsis.

Comments. This is an interesting article, however, I have some comments:

1. They grouped both culture proven sepsis & sepsis like illness (clinical sepsis) into one group, and more than 50% (12 /23) of their "sepsis group" were actually culture negative. It would have been interesting if they provided more data comparing serum Amyloid A & CRP levels in sepsis proven, clinical sepsis, non –septic and control groups.

2. What are the reference values for serum amyloid A levels in newborns? Is the cut off value they gave in their study the usual cut off value for the test? Is the test widely available?, Is it reliable, & cost effective?

3. No data was provided for statistical analyses.

In short, we need a lot more studies to prove the value of SAA in diagnosis of sepsis. JMK.

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