TABLE 3.

Precision of fluconazole MICs when 50 Candida isolates were tested in triplicate in each of three laboratories

MIC or range of MICs	% of MICs at median or within rangea
	Microdilution in RPMI 1640 broth		Etest on RPMI 1640-glucose-agarb		Etest on Mueller-Hinton agar-glucose- methylene bluec
	24 h	48 h	24 h	48 h	24 h	48 h
Median MIC	55.6	50.4	64.0	60.7	55.6	63.1
Median MIC ± 1 dilution	87.3	86.2	96.4	94.0	91.1	90.2
Median MIC ± 2 dilutions	93.8	93.1	98.7	97.4	96.7	96.7
Median MIC ± 3 dilutions	95.6	95.3	99.5	98.7	99.3	99.8

^aFor each test strain, 9 MICs were recorded and the precision of each MIC was expressed as the number of twofold dilutions away from the overall median MIC for that strain.

^bRPMI 1640 broth with 2% glucose and 1.5% agar.

^cMueller-Hinton agar with 2% glucose and 0.5 μg of methylene blue/ml.