Using Reduced Inoculum Densities of Mycobacterium tuberculosis in MGIT Pyrazinamide Susceptibility Testing to Prevent False-Resistant Results and Improve Accuracy: A Multicenter Evaluation

Table 6

Precision of MGIT PZA susceptibility test results stratified by inoculation method. Reproducibility of categorical results for each duplicate pair of isolates.

Precision	Percentage (number) by inoculation method
	BD	A	C
Precise  & accurate	72.2 (109)	87.6 (127)	93.5 (131)
Precise & inaccurate	15.2 (23)	6.9 (10)	2.9 (4)
Not precise	12.6 (19)	5.5 (8)	3.6 (5)
Subtotal	151	145	140
<2 results	1.3 (2)	5.2 (8)	8.5 (13)
Total	153	153	153

Each duplicate isolate had the same categorical susceptibility result. Each duplicate isolate had a different categorical susceptibility result. Denominators used to calculate precision percentages. Time-Out occurred in one or both of the duplicate pairs of isolates. Denominator used to calculate <2 results percentages.