Cobas b 221<4>Roche OMNI S4 system; Catalog numbers: 3337138001 and 3337138692 || The Roche Diagnostics Omni S Analyzer is a fully automated critical care analyzer intended to be used for the measurement of pH, PCO2, PO2, sodium, potassium, ionized calcium, chloride, hematocrit, glucose, lactate, urea/BUN, total hemoglobin, oxygen saturation, oxyhemoglobin, deoxyhemoglobin, carboxyhemoglobin, and methemoglobin in samples of whole blood, serum, plasma, and aqueous solutions as appropriate.