Validation of a portable monitor for assessment of cerebrospinal fluid lactate in dogs.

ABSTRACT

BACKGROUND: Cerebrospinal fluid (CSF) lactate concentration may be a useful diagnostic and prognostic biomarker in dogs. Previous studies have used methods requiring relatively large sample volumes or prolonged storage prior to analysis. An effective method to immediately quantify lactate in smaller CSF volumes would be beneficial. OBJECTIVES: The main objectives were to evaluate the utility, accuracy, and precision of a portable meter for CSF lactate analysis in dogs and to develop a provisional RI using this device. A secondary objective was to assess the effects of different storage conditions on lactate concentrations. METHODS: The Lactate Plus device was used to analyze CSF samples. Device accuracy and precision were assessed by spiking CSF samples with concentrated sodium lactate solutions and by repeated analysis of samples, respectively. The provisional RI was generated using CSF samples from dogs with unremarkable laboratory data, central nervous system imaging, and conventional cytologic and chemical CSF analysis. Select samples were analyzed before and after storage at 4°C, -20°C, and -80°C. RESULTS: Spiked samples showed lactate concentrations comparable to expected concentrations. The CV of immediate repeated measurements was 0-9.69%. Sample storage at 4°C for 24 hours showed similar results but variation was higher with other storage conditions. The provisional RI was 1.02-2.49 mmol/L. CONCLUSIONS: The Lactate Plus has acceptable accuracy and precision for the quantification of CSF lactate in dogs. Lactate in CSF is ideally quantified immediately after collection as a subset of samples show variation with storage although most stored samples show acceptable variation.