Proficiency Testing/EQA / Microbiology / Bacteriology Help Please log in to determine if you are eligible to purchase PT Programs. STOOL PATHOGEN, WITHOUT SHIGATOXIN - SPN Analytes/procedures in bold type are regulated for proficiency testing by the Centers for Medicare & Medicaid Services (CMS). Analyte Challenges per Shipment Number of Shipments Adenovirus 40/41 2 Two shipments per year C. difficile antigen/toxin 2 Rotavirus 2 Program Information Two 1.0‑mL liquid specimens For use with rapid or molecular testing methods Intended for international laboratories Shipping Schedule Shipment A: May 15 Shipment B: October 30 Guest Log in/Register