Table 4.

PPV of positive synovial fluid culture combined with SASA (95% CI)

All sites
	PPV of positive cultures/positive SASA	p valuea	PPV of positive cultures/negative SASA	p valuea
All staphylococci	92% (82 to 97)	0.04	55% (37 to 72)	0.02
S. aureus	94% (73 to 100)	1	88% (52 to 99)	1
S. epidermidis	88% (70 to 97)	0.33	50% (21 to 79)	0.13
S. lugdunensis	100% (69 to 100)	1
Other staphylococci	100% (22 to 100)	0.47	36% (13 to 66)	0.69
Hip
All staphylococci	100% (89 to 100)	0.01	47% (26 to 69)	0.04
S. aureus	100% (72 to 100)	1	67% (13 to 98)	0.37
S. epidermidis	100% (76 to 100)	0.27	50% (18 to 82)	0.18
S. lugdunensis	100% (37 to 100)	1
Other staphylococci	100% (22 to 100)	0.47	38% (11 to 72)	0.66
Knee
All staphylococci	84% (66 to 95)	0.75	70% (38 to 92)	0.67
S. aureus	86% (41 to 99)	1	100% (55 to 100)	1
S. epidermidis	77% (49 to 94)	1	50% (3 to 98)	0.51
S. lugdunensis	100% (55 to 100)	1
Other staphylococci			33.3% (2 to 87)	1

^aComparison with PPV of positive cultures alone; SASA = serum anti-staphylococcal antibodies; PPV = positive predictive values.