Evaluation of Nova StatStrip and FreeStyle Precision Pro blood ketone tests using 3-hydroxybutyrate doped samples

Background The most clinically useful blood ketone in the diagnosis, management, and recovery of diabetes ketoacidosis in both adults and children is 3-hydroxybutyrate. In the absence of laboratory routine methods, several point-of-care methods are in use, but very few clinical evaluations are published. Methods This study evaluates linearity and reproducibility of two handheld point-of-care meters for blood 3-hydroxybutyrate measurement for hospital use, Nova StatStrip, and FreeStyle Precision Pro. Whole blood from healthy volunteers was spiked with different concentrations of a 3-hydroxybutyrate solution and tested on the point-of-care instruments. The results were compared with plasma 3-hydroxybutyrate that was analyzed with a laboratory enzymatic end point spectrophotometric reference method. Results Blood 3-hydroxybutyrate on StatStrip was linear with the reference method up to approximately 4 mmol/L, and FreeStyle was linear up to 6 mmol/L. At higher concentrations, the point-of-care instruments gave falsely too low results, especially the StatStrip meter. The FreeStyle meter had better precision and less bias than StatStrip. Conclusion In the acute setting of diabetes ketoacidosis, blood 3-hydroxybutyrate in the higher ranges should be interpreted with caution as the point-of-care meters are less accurate there.