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Observational Study
. 2021 Feb;62(2):408-415.
doi: 10.1111/epi.16806. Epub 2021 Jan 8.

Prehospital lactate levels in blood as a seizure biomarker: A multi-center observational study

Carl Magnusson  1   2   3 , Johan Herlitz  1   2 , Robert Höglind  3 , Pär Wennberg  4 , Anna Edelvik Tranberg  5   6 , Christer Axelsson  1   2   3 , Johan Zelano  5   6   7
Affiliations
Observational Study

Prehospital lactate levels in blood as a seizure biomarker: A multi-center observational study

Carl Magnusson et al. Epilepsia. 2021 Feb.

Abstract

Objective: The objective of this study was to assess the value of prehospital measurement of lactate level in blood for diagnosis of seizures in cases of transient loss of consciousness.

Methods: Between March 2018 and September 2019, prehospital lactate was measured with a point-of-care device by the emergency medical services in an area serving a population of 900 000. A total of 383 cases of transient loss of consciousness were identified and categorized as tonic-clonic seizure (TCS), other seizure, syncope, or other cause, according to the final diagnosis in the electronic medical records system. Receiver operating characteristic curve analyses were used to identify the optimal lactate cut-off.

Results: A total of 383 cases were included (135 TCS, 42 other seizure, 163 syncope, and 43 other causes). The median lactate level in TCS was 7.0 mmol/L, compared to a median of 2.0 mmol/L in all other cases (P < .001). The area under the curve (AUC) of TCS vs nonepileptic causes was 0.87 (95% confidence interval [CI] 0.83-0.91). The optimal cut-off (Youden index, 67.8%) was 4.75 mmol/L, with 79% sensitivity (95% CI 71-85) and 89% specificity (95% CI 85-93) for TCS.

Significance: Prehospital lactate can be a valuable tool for identifying seizures in transient loss of consciousness. For acceptable specificity, a higher cut-off than that previously demonstrated for hospital-based measurements must be used when values obtained close to the time of the event are interpreted.

Keywords: diagnosis; epilepsy; lactate; syncope.

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Conflict of interest statement

None of the authors have any relevant conflicts of interest to disclose. We confirm that we have read the Journal's position on issues involved in ethical publication and affirm that this report is consistent with those guidelines.

Figures

FIGURE 1
FIGURE 1
Flow chart of inclusion and classification
FIGURE 2
FIGURE 2
Lactate values. (A) Prehospital lactate in the different groups. (B) Lactate value in relation to time to analysis from call to the emergency services in each group. Sz, seizure; TCS, tonic‐clonic seizure
FIGURE 3
FIGURE 3
Receiver‐operating characteristic (ROC) curve analyses. ROC curves for tonic‐clonic seizures (TCS) vs nonepileptic causes (A), TCS vs syncope (B), and TCS or other seizures vs nonepileptic causes (C)
See this image and copyright information in PMC

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