PHARM-TROL™ Particle Count Control is a product containing National Institute of Standards and Technology (NIST) traceable size standards with a measured particle count. The product was developed to provide process control data for particle counting consistency and verification of size calibration. The ready-to-use precision standard is designed for regular use in liquid particle counters. This documents the reproducibility of the particle counter by permitting a continuous record of its performance using a microsphere suspension with a known concentration. The data provides documentation for internal or customer quality audits. The product is ideal for parenteral drug manufacturers seeking interim verification of USP <788> “Particulate Matter in Injections”, Light Obscuration Particle Count Test. PHARM-TROL™ is prepared with the same exacting procedures as the USP Count Reference Standard. The product is a 15µm polystyrene microsphere suspension packaged at 3800 particles per mL in 25mL single-use quantities. It is supplied in convenient 6 or 20 bottle sets.