This leaves us with determination of the number of surface sampling sites for the qualification study. There is no regulatory guidance directed to this point for the international pharmaceutical industry. Even the Pharmaceutical Inspection Convention and Pharmaceutical Inspection Cooperation Scheme (PIC/S), which gen- erally can be counted on to provide details on almost everything microbiological, is silent on this point (6). Oddly enough, even the Parenteral Drug Association (PDA) Technical Report #13 (7) offers no help here. We are left to our own devices.