USE OF SENTINEL BLOOD CULTURE SYSTEM FOR ANALYSIS OF SPECIMENS FROM POTENTIALLY INFECTED PROSTHETIC JOINTS

The Sentinel blood culture system was used for the analysis of 657 spe cimens from infected prosthetic joints and blood cultures (83 from pro sthetic joints and 574 from standard blood cultures). The positivity r ate was similar for specimens from prosthetic joints and blood culture s (18% compared with 14%). However, there was an unacceptable rate of false positive results with specimens from prosthetic joints (58% comp ared with 8%). This high false positivity rate was due to (i) prolonge d incubation and (ii) the lack of blood in these specimens. It is ther efore recommended that the Sentinel system should only be used for the initial seven days of incubation of specimens taken from prosthetic j oints. Further incubation should take place in a standard incubator an d a terminal subculture performed after 21 days.