↵1 Pseudomonas aeruginosa ATCC 9027 was tested twice due to a delay between the ScanRDI measurements and plating of the dilutions by the reference method in the initial measurement, which resulted in ScanRDI recovery that was <70% of the reference method. When testing was repeated performing both assays simultaneously, the ScanRDI recovery was >70% of the reference method for all dilutions assayed. All ScanRDI and standard microbiological pour plate method testing should be performed simultaneously to reduce any bias that may be caused by cultures multiplying between assays.