TABLE IV

Precision of ScanRDI and Reference Plate Count Method

	ScanRDI			Reference Method (cfu)
Staphylococcus aureus ATCC 6538
Dilution	Range	Mean ± SD	%CV	Range	Mean ± SD	%CV
Stock	2494–2890	2708 ± 146	5	2640–3100	2810 ± 141	5
10⁻¹	253–294	271 ± 15	5	212–289	268 ± 25	9
10⁻²	18–37	29 ± 6	20	22–55	34 ± 10	29

Pseudomonas aeruginosa ATCC 9027
Dilution	Range	Mean ± SD	%CV	Range	Mean ± SD	%CV
Stock	2118–3338	2800 ± 390	14	2530–3360	3054 ± 225	7
10⁻¹	133–244	196 ± 42	21	230–320	286 ± 25	9
10⁻²	5–21	13 ± 6	44	25–48	36 ± 8	23

Escherichia coli ATCC 8739
Dilution	Range	Mean ± SD	%CV	Range	Mean ± SD	%CV
Stock	2422–2780	2540 ± 139	5	2270–2900	2573 ± 278	11
10⁻¹	239–302	256 ± 22	9	225–272	246 ± 15	6
10⁻²	22–44	28 ± 7	25	22–32	27 ± 3	11

Candida albicans ATCC 10231
Dilution	Range	Mean ± SD	%CV	Range	Mean ± SD	%CV
Stock	1858–2275	2074 ± 135	7	2230–2560	2418 ± 107	4
10⁻¹	199–258	227 ± 22	10	221–250	238 ± 13	5
10⁻²	14–35	23 ± 6	27	17–33	24 ± 8	22

Aspergillus brasiliensis ATCC 16404
Dilution	Range	Mean ± SD	%CV	Range	Mean ± SD	%CV
Stock	855–1244	1054 ± 116	11	700–1300	910 ± 197	22
10⁻¹	105–135	115 ± 11	9	90–170	120 ± 21	18
10⁻²	7–19	12 ± 4	35	8–16	13 ± 3	21

Bacillus atrophaeus NRRL B4418 (spores)
Dilution	Range	Mean ± SD	%CV	Range	Mean ± SD	%CV
Stock	993–1322	1184 ± 129	11	1040–1430	1166 ± 116	10
10⁻¹	123–169	150 ± 17.0	11	93–137	125 ± 15	12
10⁻²	9–24	12 ± 5.0	41	4–19	13 ± 5	36

Mixed cultures (S. aureus ATCC 6538, E. coli ATCC 8739, C. albicans ATCC 10231)
Dilution	Range	Mean ± SD	%CV	Range	Mean ± SD	%CV
Stock	1977–2206	2053 ± 93	5	1540–2460	2125 ± 271	13
10⁻¹	166–223	194 ± 18	9	192–253	219 ± 17	8
10⁻²	11–25	18 ± 5	29	18–29	23 ± 3	13