TABLE 3.

Performance of the multiplex immunoassay^a

Organism(s)	All cases		Site of prosthesis				Time since implantation
			Hip		Knee		≤3 mo		>3 mo
	Sensitivity	Specificity	Sensitivity	Specificity	Sensitivity	Specificity	Sensitivity	Specificity	Sensitivity	Specificity
Staphylococci targeted	68/94 (72.3) [62.7–80.7]	213/264 (80.7) [75.6–85.1]	38/52 (73.1) [59.9–83.8]	159/190 (83.7) [77.9–88.4]	29/39 (74.4) [59–86.2]	50/68 (73.5) [62.1–83]	9/15 (60) [34.5–81.9]	3/7 (42.9) [12.3–78.4]	57/75 (76) [65.4–84.6]	205/250 (82) [76.9–86.4]
S. aureus	36/54 (66.7) [53.4–78.2]		21/30 (70) [52–84.3]		14/21 (66.7) [44.9–84.1]		7/11 (63.6) [33.6–87.2]		27/39 (69.2) [53.6–82.1]
S. epidermidis	26/35 (74.3) [58–86.7]		16/21 (76.2) [54.9–90.7]		10/13 (76.9) [49.1–93.8]		2/4 (50) [9.4–90.6]		24/31 (77.4) [60.4–89.6]
S. lugdunensis	9/9 (100) [71.7–100]		3/3 (100) [36.8–100]		6/6 (100) [60.7–100]				9/9 (100) [71.7–100]
S. agalactiae	6/8 (75) [38.8–95.6]	250/270 (92.6) [89–95.3]	3/3 (100) [36.8–100]	181/195 (92.8) [88.5–95.9]	2/4 (50) [9.4–90.6]	63/69 (91.3) [82.8–96.4]	0/1 (0) [0–95]	7/7 (100) [65.2–100]	6/7 (85.7) [47–99.3]	237/256 (92.6) [88.9–95.3]
P. acnes	5/13 (38.5) [15.7–65.9]	235/277 (84.8) [80.2–88.7]	1/6 (16.7) [0.8–59.1]	172/200 (86) [80.7–89.5]	1/2 (50) [2.5–97.5]	60/71 (84.5) [74.7–91.6]		7/7 (100) [65.2–100]	4/12 (33.3) [11.6–62.3]	222/263 (84.4) [79.6–88.4]

^aData are no. (%) [95% confidence interval].