Comparison between capillary, venous and arterial levels of protein S100B in patients with severe brain pathology
Ramona Astrand1, Bertil Romner, Peter Reinstrup
1Clinical Sciences, Department of Neurosurgery, Lund University, Lund, Sweden. raastrand@gmail.com
Insights
Capillary S100B levels are higher than venous levels and not interchangeable. However, arterial S100B measurements can accurately predict venous S100B concentrations in neurocritical care patients.
Area of Science:
- Biochemistry
- Clinical Diagnostics
- Neuroscience
Background:
- Protein S100B is a sensitive biomarker for traumatic brain injury.
- Studies show S100B's potential in pediatric head injury.
- Capillary blood sampling is preferred in children due to venipuncture challenges.
Purpose of the Study:
- To investigate the relationship between capillary, venous, and arterial S100B measurements.
- To determine if capillary S100B levels differ from venous levels and can predict them.
- To assess if arterial S100B can substitute for venous samples in severe brain injury.
Main Methods:
- Simultaneous collection of venous, arterial, and capillary blood samples for S100B analysis.
- Daily sampling for up to 6 days in adult patients (≥18 years) in neurointensive care.
- Focus on patients with severe brain pathology.
Main Results:
- Capillary S100B samples were, on average, 0.08 μg/L higher than venous samples.
- Prediction error for venous S100B from capillary samples was 0.07 μg/L.
- Arterial S100B samples showed a mean difference of 0.01 μg/L and a prediction error of 0.03 μg/L compared to venous samples.
Conclusions:
- Capillary and venous S100B serum levels are not interchangeable and represent distinct variables.
- Arterial S100B measurements can reliably predict venous S100B concentrations.
- Findings have implications for biomarker monitoring in neurocritical care.
Background:
Protein S100B is soon in clinical use as a sensitive marker after mild traumatic head injury in adults. Initial studies of S100B in pediatric head injury have shown promising results. Venous sampling can be challenging in children and capillary samples are often a preferred option. The aim of the study was to investigate the relation between capillary, venous and arterial measurements of protein S100B, primarily by determining whether capillary S100B differ from venous and if capillary S100B can predict venous S100B levels, and secondarily, if arterial S100B samples can substitute venous samples in severely brain-injured patients.
Methods:
Venous, arterial and capillary blood samples for S100B were collected simultaneously once a day for a maximum of 6 days. Patients were ≥18 years old and admitted to neurointensive care due to severe brain pathology.
Results:
Capillary S100B samples were on average 0.08 μg/L higher than venous S100B samples. Prediction of venous concentration from capillary samples yielded a prediction error of 0.07 μg/L. The mean difference between venous and arterial samples was 0.01 μg/L. The mean prediction error was 0.03 μg/L.
Conclusions:
Capillary and venous serum S100B are not interchangeable, and should be considered as two separate, although related, variables. Arterial measurements of S100B can successfully predict the corresponding venous concentration.
