Verichem Laboratories offers a multi-level set of liquid stable and ready-to-use clinical reference materials for the calibration and calibration verification of ammonia assays. The materials feature universal compatibility and can be used with several clinical testing systems. The five-level standard kit, along with an optional stand-alone sixth level, features ammonia concentrations ranging from 10 mcg/dL to 2000 mcg/dL. Verichem’s clinical reference materials are designed to present lot-to-lot duplication, while the set point design with equidistant target concentrations addresses current CLIA requirements for calibration verification materials used for the determination of a clinical system’s accuracy, sensitivity, linearity, and reportable range. All of the available reference materials have a 24-month stability when stored at 2°C to 8°C and are packaged within translucent, polyethylene dropper vials containing a 15-mL fill volume.