Help Please log in to determine if you are eligible to purchase PT Programs. ELECTRONIC CROSSMATCH - EXM Analytes/procedures in bold type are regulated for proficiency testing by the Centers for Medicare & Medicaid Services (CMS). Procedure Challenges per Shipment Number of Shipments Electronic crossmatch 3 Two shipments per year Survey EXM assists laboratories in monitoring the performance of their electronic crossmatching system. Program Information Three simulated, ISBT‑128 labeled donor unit challenges and three corresponding red blood cell suspensions Must order in conjunction with Survey J Shipping Schedule Shipment A: February 10 Shipment C: September 8 Guest Log in/Register