The McGeer Criteria uses CFU per ml or colony-forming units per milliliter. This relies on culture and stains in order to calculate the number of viable bacterial or fungal cells per milliliter or gram of sample by dividing the number of colonies by the dilution factor. Simply summarized. CFU/mL = (number of colonies x dilution factor) / volume of culture plate. Therefore, molecular diagnostics do not provide CFU information, and McGeer’s criteria cannot be used directly. However, molecular diagnostics is still an important tool used to diagnose infectious diseases when clinically applicable.