Objective: To study the diagnostic value of determinations of serum acute phase reaction protein, such as complement 3 (C3), complement 4 (C4), prealbumin (PA) and C-reactive protein (CRP), etc., in patients with severe acute respiratory syndrome (SARS).
Methods: Serum levels of C3, C4, PA and CRP were determined by turbidimetry in 54 cases of SARS, 20 of other pneumonia and 30 normal persons.
Results: Serum concentrations of C3, C4, CRP and PA were (1.18 +/- 0.42) g/L, (1.15 +/- 0.56) g/L, (10.52 +/- 8.77) mg/L and (107 +/- 54) mg/L in SARS patients, (1.30 +/- 0.46) g/L, (0.57 +/- 0.31) g/L, (0.88 +/- 0.43) mg/L and (291 +/- 76) mg/L in patients with other pneumonia, and (1.11 +/- 0.56) g/L, (0.38 +/- 0.26) g/L, (0.42 +/- 0.26) mg/L and (376 +/- 74) mg/L in normal persons, respectively. Serum level of PA was significantly lower and levels of C4 and CRP significantly in patients with SARS higher than those in patients with other pneumonia and normal persons (P < 0.01). There was no significant difference in serum level of C3 between the three groups (P > 0.05).
Conclusion: Determination of serum level of C4, CRP and PA in suspected patients is beneficial to early differential diagnosis for SARS.