Evaluation of S100B blood level as a biomarker to avoid computed tomography in patients with mild head trauma under antithrombotic medication

Possible limited justification for systematic head computed tomography scans based solely on antithrombotic therapy in elderly patients (aged 75 or older) with mild traumatic brain injury

Rationale and objectives

Recent literature suggests that performing systematic head computed tomography (CT) scans for mild traumatic brain injury (mTBI) in patients undergoing antithrombotic therapy offers limited benefits. This study aims to evaluate a set of criteria that could potentially eliminate the need for systematic head CT scans, performed solely because of the antithrombotic treatment status, in elderly patients (aged 75 or older) presenting with mTBI.

Materials and methods

All patients aged 75 or older who underwent a head CT scan at our academic center for mTBI while on antithrombotic therapy between January and December 2022 were retrospectively included in this study. Patients were categorized into two groups. The first group, referred to as the "At-risk group", included patients with any of the following: GCS score < 15 or cognitive impairment; initial loss of consciousness; hemodynamic instability; signs of fractures; extensive subcutaneous hematoma; severe or treatment-resistant headache; vomiting; seizure; any neurological deficit; intoxication; amnesia; or a history of neurosurgery. The second group, referred to as the "Not-at-risk group", comprised patients without any of these criteria.

Results

A total of 1415 patients were included. Post-traumatic intracranial hemorrhage (P < 0.001), brain herniation (P = 0.003), and fractures (P < 0.001) occurred statistically more frequently in the At-risk group. Six post-traumatic hemorrhagic brain injuries were found in the Not-at-risk group, that did not present any of the studied criteria, and all these injuries were minor (localized SAH; millimetric SDH). Furthermore, none of these required immediate or delayed surgical intervention, and no neurological deterioration or deaths occurred in these patients.

Conclusion

In conclusion, conducting systematic head CT scans based solely on antithrombotic therapy in elderly patients aged 75 or older with mTBI might be irrelevant.

Diagnostic performance of S100B assay for intracranial hemorrhage detection in patients with mild traumatic brain injury under antiplatelet or anticoagulant therapy

The sampling of S100B protein has been proposed as a screening tool to identify patients with a low risk of post-traumatic intracranial hemorrhage. Its performance for patients on antiplatelet agents or anticoagulants is still debatable. This exploratory study evaluates the diagnostic accuracy of S100B concentrations, measured within 3 h of head trauma, to rule out intracranial hemorrhage in adults on antiplatelet or anticoagulant therapy. This prospective study enrolled adult patients presenting for head trauma within the last 3 h and under antiplatelets or anticoagulants. We hypothesized that a S100B concentration under 0,100 µg.L-1 rule out intracranial hemorrhage with a negative predictive value over 0,99. Sensitivity, specificity, positive predictive value and negative predictive value were analyzed. From June 2020 to January 2023, 155 patients were included. 119 patients had a S100B level at 0,100 µg.L-1 or over. 8 had an intracranial hemorrhage. The sensitivity of S100B was 1 (95%CI 0,68-1), specificity was 0,25 (95%CI 0,18 - 0,32), positive predictive value was 0,07 (95%CI 0.03-0.13), negative predictive value was 1 (95%CI 0,90 - 1). This study suggests that when performed in a 3-hour period after mild head trauma, S100B measurement is an accurate screening tool to rule out intracranial hemorrhage in patients treated with antiplatelet agents or anticoagulants.

Diagnostic Accuracy of S100B in Predicting Intracranial Abnormalities on CT Imaging Following Mild Traumatic Brain Injury: A Systematic Review and Meta-analysis

Traumatic brain injury (TBI) is a major cause of health loss and disabilities globally, burdening health care systems. Mild TBI is a common cause of emergency department visits. Computed tomography (CT) scans are the mainstay for acute TBI imaging. S100 calcium-binding protein B (S100B) biomarker is promising for predicting intracranial lesions on CTs in mild TBI. A comprehensive search of the literature was conducted on PubMed, Google Scholar, and Cochrane electronic databases to find eligible studies reporting the diagnostic performance of S100B. A meta-analysis was conducted to evaluate the predictive ability of S100B for CT imaging abnormalities. Of 1545 articles, 32 were included in our meta-analysis. At the threshold of 0.1 μg/L, a bivariate model showed a sensitivity of 89% (95% confidence interval [CI] 83-92) with a specificity of 32% (95% CI 26-39). The aggregate analysis containing all cutoffs showed the optimal cutoff of 0.751 μg/L with a sensitivity of 64% (95% CI 32-87) and a specificity of 85% (95% CI 76-92). The optimal diagnostic performance of S100B in patients with Glasgow Coma Scale 14-15 was estimated to be 0.05 μg/L, with a sensitivity of 98% (95% CI 92-99) and a negative predictive value of 99%. These findings indicate that S100B analysis could minimize the need for unnecessary CT scans in individuals with mild TBI. The test's diagnostic accuracy improves when the S100B analysis is done within 3 h of the injury. However, further research is warranted to validate its superiority to other biomarkers before considering it the standard routine for managing mild TBI.

Minor head injury in anticoagulated patients: performance of biomarkers S100B, NSE, GFAP, UCH-L1 and Alinity TBI in the detection of intracranial injury. A prospective observational study

OBJECTIVES

Data in literature indicate that in patients suffering a minor head injury (MHI), biomarkers serum levels could be effective to predict the absence of intracranial injury (ICI) on head CT scan. Use of these biomarkers in case of patients taking oral anticoagulants who experience MHI is very limited. We investigated biomarkers as predictors of ICI in anticoagulated patients managed in an ED.

METHODS

We conducted a single-cohort, prospective, observational study in an ED. Our structured clinical pathway included a first head CT scan, 24 h observation and a second CT scan. The outcome was delayed ICI (dICI), defined as ICI on the second CT scan after a first negative CT scan. We assessed the sensitivity (SE), specificity (SP), negative predictive value (NNV) and positive predictive value (PPV) of the biomarkers S100B, NSE, GFAP, UCH-L1 and Alinity TBI in order to identify dICI.

RESULTS

Our study population was of 234 patients with a negative first CT scan who underwent a second CT scan. The rate of dICI was 4.7 %. The NPV for the detection of dICI were respectively (IC 95 %): S100B 92.7 % (86.0-96.8 %,); ubiquitin C-terminal hydrolase-L1 (UCH-L1) 91.8 % (83.8-96.6 %); glial fibrillary protein (GFP) 100 % (83.2-100 %); TBI 100 % (66.4-100 %). The AUC for the detection of dICI was 0.407 for S100B, 0.563 for neuron-specific enolase (NSE), 0.510 for UCH-L1 and 0.720 for glial fibrillary acidic protein (GFAP), respectively.

CONCLUSIONS

The NPV of the analyzed biomarkers were high and they potentially could limit the number of head CT scan for detecting dICI in anticoagulated patients suffering MHI. GFAP and Alinity TBI seem to be effective to rule out a dCI, but future trials are needed.

Traumatic Brain Injury in Patients under Anticoagulant Therapy: Review of Management in Emergency Department

The best management of patients who suffer from traumatic brain injury (TBI) while on oral anticoagulants is one of the most disputed problems of emergency services. Indeed, guidelines, clinical decision rules, and observational studies addressing this topic are scarce and conflicting. Moreover, relevant issues such as the specific treatment (and even definition) of mild TBI, rate of delayed intracranial injury, indications for neurosurgery, and anticoagulant modulation are largely empiric. We reviewed the most recent evidence on these topics and explored other clinically relevant aspects, such as the promising role of dosing brain biomarkers, the strategies to assess the extent of anticoagulation, and the indications of reversals and tranexamic acid administration, in cases of mild TBI or as a bridge to neurosurgery. The appropriate timing of anticoagulant resumption was also discussed. Finally, we obtained an insight into the economic burden of TBI in patients on oral anticoagulants, and future directions on the management of this subpopulation of TBI patients were proposed. In this article, at the end of each section, a "take home message" is stated.

Clinical value of S100B in detecting intracranial injury in elderly patients with mild traumatic brain injury

OBJECTIVE

The biomarker S100B is a sensitive biomarker to detect traumatic intracranial injury in patients mild traumatic brain injury (mTBI). Higher blood values of S100B, resulting in lower specificity and decreased head computed tomography (CT) reduction has been regarded as one of shortcomings in patients over 65 years of age. The purpose of this study was to assess the accuracy of plasma S100B to detect intracranial injury in elderly patients with mTBI.

METHODS

A posthoc analysis was performed of a larger prospective cohort study. Previous recorded patient variables and plasma values of S100B from patients with mTBI who presented to the Emergency Department (ED) within 6 h of injury, underwent a head CT and had a blood sample drawn as part of their routine clinical care, were partitioned at 65 years of age. Sensitivity, specificity, negative predictive value, and positive predictive value of plasma S100B for predicting traumatic intracranial lesions on head CT, with a cut-off set at 0.105 μg/L, were calculated. Results were compared with data from an additional systematic review on the accuracy of S100B to detect intracranial injury in elderly patients with mTBI.

RESULTS

Data of 240 patients (48.4 %) of 65 years or older were analyzed. Sensitivity and NPV of S100B were 89 % and 86 % respectively, which is lower than among younger patients (both 97 %). The specificity decreased stepwise with older age: 22 %, 18 %, and 5 % for the age groups 65-74, 75-84, and ≥ 85 years old, respectively. The meta-analysis comprised 4 studies and the current study with data from 2166 patients. Pooled data estimated the sensitivity of s100B as 97.4 % (95 % CI 83.3-100 %) and specificity as 17.3 % (95 % CI 9.5-29.3 %) to detect intracranial injury in elderly patients with mTBI.

CONCLUSION

The biomarker S100B at the routine threshold has a limited clinical value in the management of elderly mTBI patients mainly due to a poor specificity leading to only a small decrease in head CTs. Alternate cut-off values and combining several plasma biomarkers with clinical variables may be useful strategies to increase the accuracy of S100B in (subgroups of) elderly mTBI patients.

Diagnostic performance of S100B as a rule-out test for intracranial pathology in head-injured patients presenting to the emergency department who meet NICE Head Injury Guideline criteria for CT-head scan

BACKGROUND

Traumatic brain injury is a common ED presentation. CT-head utilisation is escalating, exacerbating resource pressure in the ED. The biomarker S100B could assist clinicians with CT-head decisions by excluding intracranial pathology. Diagnostic performance of S100B was assessed in patients meeting National Institute of Health and Clinical Excellence Head Injury Guideline (NICE HIG) criteria for CT-head within 6 and 24 hours of injury.

METHODS

This multicentre prospective observational study included adult patients presenting to the ED with head injuries between May 2020 and June 2021. Informed consent was obtained from patients meeting NICE HIG CT-head criteria. A venous blood sample was collected and serum was tested for S100B using a Cobas Elecsys-S100 module; >0.1 µg/mL was the threshold used to indicate a positive test. Intracranial pathology reported on CT-head scan by the duty radiologist was used as the reference standard to review diagnostic performance.

RESULTS

This study included 265 patients of whom 35 (13.2%) had positive CT-head findings. Within 6 hours of injury, sensitivity of S100B was 93.8% (95% CI 69.8% to 99.8%) and specificity was 30.8% (22.6% to 40.0%). Negative predictive value (NPV) was 97.3% (95% CI 84.2% to 99.6%) and area under the curve (AUC) was 0.73 (95% CI 0.61 to 0.85; p=0.003). Within 24 hours of injury, sensitivity was 82.9% (95% CI 66.4% to 93.44%) and specificity was 43.0% (95% CI 36.6% to 49.7%). NPV was 94.29% (95% CI 88.7% to 97.2%) and AUC was 0.65 (95% CI 0.56 to 0.74; p=0.046). Theoretically, use of S100B as a rule-out test would have reduced CT-head scans by 27.1% (95% CI 18.9% to 36.8%) within 6 hours and 37.4% (95% CI 32.0% to 47.2%) within 24 hours. The risk of missing a significant injury with this approach would have been 0.75% (95% CI 0.0% to 2.2%) within 6 hours and 2.3% (95% CI 0.5% to 4.1%) within 24 hours.

CONCLUSION

Within 6 hours of injury, S100B performed well as a diagnostic test to exclude significant intracranial pathology in low-risk patients presenting with head injury. In theory, if used in addition to NICE HIGs, CT-head rates could reduce by one-quarter with a potential miss rate of <1%.

The Potential of S100 Calcium-Binding Protein B and Glial Fibrillary Acid Protein in Predicting the Intracranial Lesions in Mild Traumatic Brain Injury: A Systematic Review of Literature

ABSTRACT AIM: To summarize the current evidence of S100B and GFAP in predicting intracranial lesions after mTBI. MATERIAL AND METHODS: We searched publications on biomarkers in mTBI from Web of Science, PubMed, and Scopus between January 1990 and July 2021. We included RCTs, cohort, case control, and cross-sectional studies that involved patients with acute closed mTBI in all age group in which head CT scan and blood-based biomarkers (GFAP and S100B) examination were conducted under 24 hours. This study was registered in Open Science Framework. RESULTS: The initial search identified 4.937 article, in which 127 were included for full-text assessment. A total of 16 articles were finally included. No RCT was found in literature searching. Thirteen studies were studying S100B and three studies were studying GFAP. Nine out of 13 S100B studies shows a promising result with ≥ 95% sensitivity for detecting intracranial lesions.  Majorities (11 /13) studies of  S100B confirmed that S100B reduced the unnecessary usage of CT scan. GFAP concentration significantly increased in CT+ patient than CT- patient. No specific GFAP cut off value between the studies was found. CONCLUSION: The result showed that S100B and GFAP had potential to predict the occurrence of intracranial lesions. Variance between methodologies and cut off value hindered the quality of evidence, especially in GFAP. KEYWORDS: mild traumatic brain injury, S100B, GFAP.

S100B, GFAP, UCH-L1 and NSE as predictors of abnormalities on CT imaging following mild traumatic brain injury: a systematic review and meta-analysis of diagnostic test accuracy

Biomarkers such as calcium channel binding protein S100 subunit beta (S100B), glial fibrillary acidic protein (GFAP), ubiquitin c-terminal hydrolase L1 (UCH-L1) and neuron-specific enolase (NSE) have been proposed to aid in screening patients presenting with mild traumatic brain injury (mTBI). As such, we aimed to characterise their accuracy at various thresholds. MEDLINE, SCOPUS and EMBASE were searched, and articles reporting the diagnostic performance of included biomarkers were eligible for inclusion. Risk of bias was assessed using the QUADAS-II criteria. A meta-analysis was performed to assess the predictive value of biomarkers for imaging abnormalities on CT. A total of 2939 citations were identified, and 38 studies were included. Thirty-two studies reported data for S100B. At its conventional threshold of 0.1 μg/L, S100B had a pooled sensitivity of 91% (95%CI 87-94) and a specificity of 30% (95%CI 26-34). The optimal threshold for S100B was 0.72 μg/L, with a sensitivity of 61% (95% CI 50-72) and a specificity of 69% (95% CI 64-74). Nine studies reported data for GFAP. The optimal threshold for GFAP was 626 pg/mL, at which the sensitivity was 71% (95%CI 41-91) and specificity was 71% (95%CI 43-90). Sensitivity of GFAP was maximised at a threshold of 22 pg/mL, which had a sensitivity of 93% (95%CI 73-99) and a specificity of 36% (95%CI 12-68%). Three studies reported data for NSE and two studies for UCH-L1, which precluded meta-analysis. There is evidence to support the use of S100B as a screening tool in mild TBI, and potential advantages to the use of GFAP, which requires further investigation.

Plasma-based S100B testing for management of traumatic brain injury in emergency setting

Background

Serum biomarker S100B has been explored for its potential benefit to improve clinical decision-making in the management of patients suffering from traumatic brain injury (TBI), especially as a pre-head computed-tomography screening test for patients with mild TBI. Although being already included into some guidelines, its implementation into standard care is still lacking. This might be explained by a turnaround time (TAT) too long for serum S100B to be used in clinical decision-making in emergency settings.

Methods

S100B concentrations were determined in 136 matching pairs of serum and lithium heparin blood samples. The concordance of the test results was assessed by linear regression, Passing Pablok regression and Bland-Altman analysis. Bias and within- and between-run imprecision were determined by a 5 × 4 model using pooled patient samples. CT scans were performed as clinically indicated.

Results

Overall, S100B levels between both blood constituents correlated very well. The suitability of S100B testing from plasma was verified according to ISO15189 requirements. Using a cut-off of 0.105 ng/ml, a sensitivity and negative predictive value of 100% were obtained for identifying patients with pathologic CT scans. Importantly, plasma-based testing reduced the TAT to 26 min allowing for quicker clinical decision-making. The clinical utility of integrating S100B in TBI management is highlighted by two case reports.

Conclusions

Plasma-based S100B testing compares favorably with serum-based testing, substantially reducing processing times as the prerequisite for integrating S100B level into management of TBI patients. The proposed new clinical decision algorithm for TBI management needs to be validated in further prospective large-scale studies.

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Plasma-based S100B testing reduces turnaround time to 26 minutes and thus enables its use in the emergency department.

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Plasma- and serum-based S100B testing demonstrate commutability of results.

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Clinical cases demonstrate the benefit of elevated S100B levels as an indicator for second-look CT re-evaluation.

A "hot Spot"-Enhanced paper lateral flow assay for ultrasensitive detection of traumatic brain injury biomarker S-100β in blood plasma

Currently colorimetric paper lateral flow strips (PLFS) encounter two major limitations, that is, low sensitivity and severe interference from complex sample matrices such as blood. These shortcomings limit their application in detection of low-concentration analytes in complex samples. To solve these problems, a PLFS has been developed by utilizing surface-enhanced Raman scattering (SERS) for sensing signal transduction. In particular, a hierarchical three-dimensional nanostructure has been designed to create "hot spots", which can significantly amplify the SERS sensing signal, leading to high sensitivity. As a result, this PLFS has demonstrated a limit of detection (LOD) of 5.0 pg mL^-1 toward detection of S-100β, a traumatic brain injury (TBI) protein biomarker in blood plasma. The PLFS has been successfully used for rapid measurement of S-100β in clinical TBI patient samples taken in the emergency department. Availability of PLFS for blood testing would shift the paradigm of TBI patient management and clinical outcome in emergency departments. It is expected that this type of PLFS can be adapted for rapid detection of various human diseases due to its capability of measuring a low level of protein blood biomarkers in complex human fluids.

Neuron-Specific Markers and their Correlation with Neurological Scales in Patients with Acute Neuropathologies

In predicting outcomes in patients with acute brain injury, current practice focuses special attention on neuron-specific proteins that reliably reflect the severity of the lesion. Further studies of molecular markers and their specificity and sensitivity could contribute to broadening the understanding of pathophysiological, diagnostic, and prognostic methods, which is vital to reducing the mortality and disability associated with these critical conditions. The purpose of this study was to assess the biomarkers of brain lesions and their correlative relations with the integral Glasgow Coma Scale (GCS) and National Institutes of Health Stroke Scale (NIHSS) in predicting severity and treatment outcomes in patients with acute neuropathologies. Ninety patients were examined, including those with traumatic brain lesions (16.6%, n = 15), hemorrhagic stroke (52.2%, n = 47), and ischemic stroke (31.1%, n = 28). Patients were classified into two groups according to the outcome of the disease: those who survived (group I, 57.8%, n = 52) and those who died (group II, 42.2%, n = 38). In comparison with the survivors, the group of patients who died demonstrated an initial increase in neuron-specific enolase (NSE) by 1.23 and S100 by 6.45 times, and in dynamics by 1.5 and 7.4 times. A significant correlation with NIHSS and GCS was determined for NSE (r = 0.1149; P = 0.3073 and r = -0.0758; P = 0.5011) and for S100 (r = 0.3243; P = 0.0031 and r = -0.2661; P = 0.0163). The receiver operating characteristic (ROC) curves were 0.828 for S100 and 0.712 for NSE. The degree of sensitivity and specificity of the markers was studied. Increased levels of S100 and NSE correlated with NIHSS and GCS, with sensitivity of 80.77 and 63.46% and specificity of 42.11 and 73.68%, respectively, and were predictive of adverse disease outcome. The survival analysis showed that early detection of these biomarkers enables the timely prognostication of the progression of secondary brain injury and aids in implementing treatment.

Prospective comparison of capillary and venous brain biomarker S100B: capillary samples have large inter-sample variation and poor correlation with venous samples

Background

Guidelines for the emergency management of mild traumatic brain injury have been used for over a decade and are considered safe. However, they recommend computerized tomography for at least half of these patients. The Scandinavian Neurotrauma Committee guideline uses serum S100B protein level to rule out intracranial hemorrhage. Analysis of capillary serum S100B protein level has not yet been employed for this purpose. The primary aim of this study was to investigate the correlation and agreement of capillary and venous serum S100B protein level over a spectrum of concentrations typical for mild traumatic brain injury.

Methods

Eighteen patients with traumatic intracranial hemorrhage and 39 volunteers without trauma to the head within the past 7 days were recruited. Blood was sampled from patients with intracranial hemorrhage daily up to four consecutive days and healthy volunteers were sampled once during the study. One venous and two capillary samples were drawn at each sampling event. Samples were analyzed using the Cobas e411 S100 electrochemiluminescence assay.

Results

Median serum S100B protein level of capillary sampling 1 was 0.12 (IQR 0.075–0.21) μg/l and median serum S100B protein level of capillary sampling 2 was 0.13 (IQR 0.08–0.22) μg/l. Median serum S100B protein level of all venous samples was 0.05 (IQR 0.03–0.07) μg/l.

Correlation plots of capillary and venous samples showed poor correlation and Bland-Altman plots showed a large dispersion of samples and wide limits of agreement.

Conclusion

The results of this study indicate that correlation and agreement between capillary and venous samples are low, and because of this, we cannot recommend studies on capillary serum S100B protein level to rule out intracranial hemorrhage in mild traumatic brain injury. Given the limitations of the current sampling and analysis methods of capillary protein S100B protein level, we conclude that evaluating its predictive ability to rule out intracranial hemorrhage should be withheld until more reliable methods can be incorporated into the study design.

Electronic supplementary material

The online version of this article (10.1186/s12245-019-0239-6) contains supplementary material, which is available to authorized users.

Intérêt clinique des concentrations sériques de la protéine S100β dans l’évaluation des patients traumatisés crâniens

Les recommandations de la Société française de médecine d’urgence concernant la prise en charge des patients traumatisés crâniens légers ont été éditées en 2012, complétées par des recommandations sur la bonne utilisation du biomarqueur S100β deux ans plus tard. Grâce à son excellente valeur prédictive négative, la protéine S100β utilisée à travers des règles strictes de prescription a été définie comme une alternative solide à la tomodensitométrie. Cependant, plusieurs questions restent en suspens concernant le délai maximum de réalisation du prélèvement par rapport à l’heure du traumatisme, l’impact médicoéconomique, les variations en rapport avec l’âge du patient, l’impact des agents anticoagulants ou antiagrégants plaquettaires et l’utilité du dosage sérique de cette protéine dans d’autres cadres nosologiques.