Rapid diagnosis of central-venous-catheter-related bloodstream infection without catheter removal

Background Current methods for the diagnosis of bloodstream infection relat ed to central venous catheters (CVC) are slow and in many cases require cat heter removal. Since most CVC that are removed on suspicion of causing infe ction prove not to be infected, removal of catheters unnecessarily exposes patients to the risks associated with reinsertion. Methods The gram slain and acridine-orange leucocyte cytospin test (AOLC) i s rapid (30 min), inexpensive, and requires only 100 mu L catheter blood (t reated with edetic acid) and the use of light and ultraviolet microscopy. W e assessed the gram stain and AOLC lest in suspected cases of catheter-rela ted bloodstream infection, in comparison with two methods requiring cathete r removal (tip roll and tip flush), and a third technique, done in situ (en doluminal brush) in conjunction with quantitative peripheral-blood cultures . Findings 128 cases of suspected catheter-related bloodstream infection were assessed in 124 adult surgical patients (median duration of CVC placement was 16 days). In 112 (88%) cases CVC blood was obtainable. Catheter-related bloodstream infection was diagnosed in 50 cases (culture of the same organ ism from the catheter, in significant numbers, and from peripheral-blood cu lture). The sensitivity of the gram stain and AOLC test was 96% and the spe cificity was 92%, with a positive predictive value of 91% and a negative pr edictive value of 97%. By comparison, the tip-roll, tip-flush, and endolumi nal-brush methods had sensitivities of 90%, 95%, and 92%, and specificities of 55%, 76%, and 98%, respectively. Interpretation The gram stain and AOLC test is a simple, and rapid method f or the diagnosis of catheter-related bloodstream infection. This diagnostic method compares favourably with other diagnostic methods, particularly tho se that require the removal of the catheter, and can permit early targeted antimicrobial therapy.