A recently available portable clinical analyzer (PCA), which examines sodium, potassium, chloride, glucose, urea nitrogen, and hematocrit levels on 60 microL of blood and calculates hemoglobin and osmolality levels within 2 minutes, was evaluated. Blood from 574 patients was drawn by emergency department staff, who immediately tested the samples with the PCA and transported them for plasma analysis on a reference analyzer in the clinical laboratory. Correlations between the PCA and the reference analyzer were as follows: R2 = 0.987 for urea nitrogen; R2 = 0.97, glucose; R2 = 0.937, K;R2 = 0.79, hematocrit; R2 = 0.751, sodium; and R2 = 0.689 for chloride. With its rapid turnaround, small sample requirement, and ease of operation, the PCA is most useful in an emergency department setting, where immediate access to clinically relevant laboratory testing is required in support of urgent clinical decision-making.