Table 4.

Mean values of diagnostic measures between infected and not infected hips

Diagnostic measure	Infected	Not infected	p value
ESR (mm/hr) (n = 131; 18 infected)	50 ± 25 (10–108)	18 ± 17 (1–99)	< 0.001*
CRP (mg/L) (n = 129; 17 infected)	65 ± 94 (4–340)	13 ± 25 (0.03–199.5)	0.0432*
Synovial fluid WBC count (cells/μL) (n = 102†; 11 infected)	25,547 ± 29,064 (6800–106,129)	1720 ± 3260 (27–21,300)	0.0432*
%PMN (n = 102‡; 11 infected)	89 ± 8 (74–100)	52 ± 29 (1–97)	< 0.001*

Values are expressed as mean ± SD with range in parentheses; controlled for error inflation using the stepdown Bonferroni method; *significantly different at the 0.05 level with the stepdown Bonferroni correction method; ^†n reflects 39 synovial fluid samples excluded (from 141 samples originally available for review) for inaccuracy as described in Materials and Methods; ^‡n reflects 10 synovial fluid samples excluded (from 112 samples originally available for review with a differential) for inaccuracy described in Materials and Methods; ESR = erythrocyte sedimentation rate; CRP = C-reactive protein; Synovial WBC = synovial fluid WBC count; %PMN = percentage polymorphonuclear cells.