TABLE 3.

Estimated annual cost, processing time, and yield of positive results for toxigenic Clostridium difficile assays

Assaya	No. of specimens positive for toxigenic C. difficileb	Cost (US$)c			Daily processing time (h) (% of specimens)
		Annual	Per specimen	Per positive specimen
AB-Q	115d	46,562	15.02	405	<1
Two-step GDH-Q/AB-Q	115	55,942	18.05	486	<1.5
CYT	208	110,546	35.66	533	≤48
Three-step GDH-Q/AB-Q→CYT	208	75,680	24.41	365	<1.5 (87.7)
					≤48 (12.3)
DPCR	346e	125,767	40.57	363	≤5
Two-step GDH-Q/DPCR	297	109,193	35.22	368	<1 (83.7)
					≤5 (16.3)
Three-step GDH-Q/AB-Q/DPCR	297	126,121	40.68	425	<1.5 (87.7)
					≤5 (12.3)

^aFor abbreviations, see Table 1.

^bBased on annual volume of 3,100 specimens (506 tested in 2nd step, 381 in 3rd step), 11.4% (n = 354) prevalence, and data from Tables 1 and 2.

^cEstimated cost per test with labor and benefits at $50/h: AB-Q, $15.02 batched and $21.68 singly; GDH-Q, $14.51 batched; CYT, $51.75 batched; DPCR, $40.57 in batch of nine tests and $184 singly, for $127 in an average batch of 1.5 tests.

^dYield assumes all GDH-Q-negative specimens to be AB-Q-negative.

^eYield assumes all GDH-Q-positive, AB-Q-positive specimens to be DPCR-positive.