β-Hydroxybutyrate is a byproduct of lipid metabolism and the predominant metabolite in ketosis. Levels of β-hydroxybutyrate have clinical use in the diagnosis and management of diabetic ketoacidosis and may be useful in the treatment of refractory epilepsy. A new STAT-Site M analyzer (Stanbio Laboratory, Boerne, Tx) is available for the analysis of β-hydroxybutyrate ketone levels in serum or plasma.
The STAT-Site M β-hydroxybutyrate ketone test was compared with the KetoSite test on the STAT-Site analyzer at a tertiary, acute care hospital in New England. Precision and linearity were evaluated using control and patient serum specimens.
STAT-Site M β-hydroxybutyrate precision (6.2%-6.6% coefficient of variation [CV]) was compared with the KetoSite test (4.4%-13.8% CV). Correlation demonstrated excellent agreement by least-squares regression: STAT-Site M= 0.09 + 0.94X; r = 0.997; Sy.x = 0.14 mM; N = 63 samples. The difference plot noted a slight negative bias that was not clinically or statistically significant by the Student t test for dependent samples (P = 0.71; not significant; mean of X = 1.36 mM; mean of Y = 1.37 mM). Replicate reproducibility of patient samples was better on the STAT-Site M β-hydroxybutyrate test (4.1% CV) compared with the KetoSite on the STAT-Site analyzer (5.2%). Linearity was proven from 0.1 to 6.9 mM.
The STAT-Site M provides comparable performance to the currently marketed KetoSite test and is easy to use. With a wider reportable range (0.1-7.0 mM for the STAT-Site M β-hydroxybutyrate test vs 0.1-2.0 mM for the KetoSite test), fewer specimens require dilution. The STAT-Site M is smaller, more portable, and may be more adaptable to point-of-care use.