@article {Woolnoughp2551, author = {Kerry Woolnough and Imran Hussain}, title = {Late-breaking abstract: When is pleural fluid microbiology useful?}, volume = {38}, number = {Suppl 55}, elocation-id = {p2551}, year = {2011}, publisher = {European Respiratory Society}, abstract = {Introduction: It is routine clinical practice, and recommended by the British Thoracic Society, that fluid is sent for culture following diagnostic thoracocentesis.Few studies have evaluated the yield from sending all pleural fluid specimens for culture in day to day practice. Culture yield has, however, been studied in cohorts of patients where pleural infection is suspected - with a sensitivity of 54\%.We wished to ascertain what our yield is from pleural fluid culture when used as part of a routine workup for an undiagnosed pleural effusion and whether positive cultures were associated with raised inflammatory markers (WCC and CRP).Methods: We retrospectively analysed all pleural fluid samples sent for culture over the previous 12 months. All specimens were cultured for aerobic and anaerobic bacteria, fungi and mycobacterium. Pleural fluid protein, LDH content, serum CRP and WCC were also recorded.Results: 485 samples were sent for culture over the 12 month period. There were 42 (8.7\%) positive cultures, of which 4 were excluded as contaminants.20 different organisms were isolated. Streptococcus anginosus and Mycobacterium tuberculosis were the most common. 47\% of these positive samples were exudates, none were transudates. The remainder of these specimens (53\%) had no pleural fluid biochemistry performed.We found a positive yield of 7.8\% out of the 485 pleural fluid samples studied. A clear association was found between yield and a raised CRP and WCC with a raised CRP found in 97\% of positive cultures and an increased WCC in 75\%.Conclusions: Routine culture of pleural fluid is neither cost-effective nor clinically useful and should only be requested when pleural infection is suspected, both clinically and biochemically.}, issn = {0903-1936}, URL = {https://erj.ersjournals.com/content/38/Suppl_55/p2551}, eprint = {https://erj.ersjournals.com/content}, journal = {European Respiratory Journal} }