Research article

Serum S100B levels after meningioma surgery: A comparison of two laboratory assays

Sharon Einav¹ , Eyal Itshayek^{* 2} , Jeremy D Kark^{* 3} , Haim Ovadia^{* 4} , Carolyn F Weiniger^{* 5} and Yigal Shoshan^{* 6}

¹The Intensive Care Unit of the Shaare Zedek Medical Center, affiliated with the Hebrew University, POB 3235, Jerusalem 91031, Israel

²The Department of Neurosurgery, Hadassah Hebrew University Medical Center, Jerusalem, Israel

³The Epidemiology Unit, Hadassah Hebrew University Medical Center, Jerusalem, Israel

⁴The Department of Neurology, Agnes Ginges Center for Human Neurogenetics, Hadassah Hebrew University Medical Center, Jerusalem, Israel

⁵The Department of Anesthesia, Hadassah Hebrew University Medical Center, Jerusalem, Israel

⁶The Department of Neurosurgery, Hadassah Hebrew University Medical Center, Jerusalem, Israel

author email corresponding author email* Contributed equally

BMC Clinical Pathology 2008, 8:9doi:10.1186/1472-6890-8-9

Published:	19 September 2008

Abstract

Background

S100B protein is a potential biomarker of central nervous system insult. This study quantitatively compared two methods for assessing serum concentration of S100B.

Methods

A prospective, observational study performed in a single tertiary medical center. Included were fifty two consecutive adult patients undergoing surgery for meningioma that provided blood samples for determination of S100B concentrations. Eighty samples (40 pre-operative and 40 postoperative) were randomly selected for batch testing. Each sample was divided into two aliquots. These were analyzed by ELISA (Sangtec) and a commercial kit (Roche Elecsys^®) for S100B concentrations. Statistical analysis included regression modelling and Bland-Altman analysis.

Results

A parsimonious linear model best described the prediction of commercial kit values by those determined by ELISA (y = 0.045 + 0.277*x, x = ELISA value, R² = 0.732). ELISA measurements tended to be higher than commercial kit measurements. This discrepancy increased linearly with increasing S100B concentrations. At concentrations above 0.7 μg/L the paired measurements were consistently outside the limits of agreement in the Bland-Altman display. Similar to other studies that used alternative measurement methods, sex and age related differences in serum S100B levels were not detected using the Elecsys^® (p = 0.643 and 0.728 respectively).

Conclusion

Although a generally linear relationship exists between serum S100B concentrations measured by ELISA and a commercially available kit, ELISA values tended to be higher than commercial kit measurements particularly at concentrations over 0.7 μg/L, which are suggestive of brain injury. International standardization of commercial kits is required before the predictive validity of S100B for brain damage can be effectively assessed in clinical practice.