TABLE 3.

Percentages of agreement and correlation indexes between MICs obtained by the NCCLS reference AST method and MICs obtained both visually and spectrophotometrically^a

Method of endpoint determination	Time of incubation (h)	Antifungal agent
		AMB		5FC		FLC		ITC		KTC		VRC
		%	r	%	r	%	r	%	r	%	r	%	r
Visual inspection	24	92	0.608∗	93	0.895∗	92	0.874∗	94	0.849∗	99	0.824∗	96	0.897∗
	48	97	0.673∗	98	0.848∗	93	0.847∗	95	0.876∗	97	0.790∗	95	0.886∗
Spec-50%	24	72	0.286	98	0.913∗	97	0.899∗	96	0.886∗	95	0.902∗	97	0.900∗
	48	87	0.512∗	91	0.783∗	95	0.885∗	94	0.888∗	95	0.886∗	94	0.904∗
Spec-80%	24	91	0.553∗	96	0.805∗	92	0.873∗	92	0.815∗	88	0.711∗	89	0.807∗
	48	92	0.421	94	0.799∗	91	0.806∗	89	0.774∗	91	0.734∗	90	0.846∗
Spec-95%	24	98	0.654∗
	48	94	0.623∗

^aThe NCCLS reference method uses RPMI, an inoculum of 10³ CFU/ml, and a visual reading of optical density at 48 h of incubation. The tested method uses RPMI–2%G, an inoculum of 10⁵ CFU/ml, and spectrophotometric determinations of optical density after 24 and 48 h of incubation. Data are for 60 strains tested. %, percentage of agreement between AST methods; r, correlation index expressed over a maximum value of 1. An asterisk indicates a correlation index with a statistically significant P value of <0.01.