Abstract
Background: Brain injury after head trauma can be detected by S-100B measurements in serum. Recent preliminary studies indicate that urinary levels of S-100B are also increased after head injury, a finding that is of possible clinical value. The aims of the present study are two-fold: to compare serum measurements of two assays, the Liaison Sangtec®100 system and the Elecsys®S100 test, and to investigate to what extent they can detect and measure S-100B in urine.
Methods: A total of 191 serum and 174 urine samples from 107 patients (children aged between 1 and 18 years following head trauma) were measured with both assays. The results were compared using correlation analysis and Bland-Altman difference plots.
Results: Serum values of the Sangtec® system ranged from 0.02 to 2.28 μg/L, and from 0.005 to 2.13 μg/L for the Elecsys® test. Comparisons showed a clear correlation (correlation coefficient 0.80) but not an agreement between the methods. The Sangtec® system could only detect S-100B in 20 out of 174 urine samples (range 0.02–0.06 μg/L), whereas the Elecsys® test could detect S-100B in 171 samples (range 0.005–0.14 μg/L). No clear relation was observed between the two methods in urine analysis (correlation coefficient 0.60).
Conclusion: The Sangtec® and Elecsys® assays are not interchangeable methods when analyzing S-100B in serum or urine samples after head injury.
Clin Chem Lab Med 2008;46:1025–9.
©2008 by Walter de Gruyter Berlin New York
