Table 4. Cycle threshold (Ct) values for upE measured with duplicate sputum samples following processing using three homogenization methods.

Homogenization by	Sample N (Results N)	N of positive results (%)	Ct value from positive samples, mean±SD (range)	P value*
PK-DNase 1	15 (30)	30 (100)	33.6±1.3 (31.1-35.4)	0.11
PBS	15 (30)	25 (83.3)	35.8±1.2 (34.7-39.0)	<0.0001
NALC-sodium citrate	15 (30)	26 (86.7)	35.7±1.5 (33.9-38.6)	<0.0001

^*The significance level was calculated by using the one-sample t-test. The null hypothesis was that the test mean was equal to the control mean of 33.2.

Abbreviations: NALC, N-acetyl-L-cysteine; PBS, phosphate-buffered saline; PK, proteinase K.