title: Identifying Malignant Pleural Effusion by A Cancer Ratio (Serum LDH: Pleural Fluid ADA Ratio).
abstract: OBJECTIVE
  We studied the diagnostic potential of serum lactate dehydrogenase (LDH) in malignant pleural effusion.
  
  
  METHODS
  Retrospective analysis of patients hospitalized with exudative pleural effusion in 2013.
  
  
  RESULTS
  Serum LDH and serum LDH: pleural fluid ADA ratio was significantly higher in cancer patients presenting with exudative pleural effusion. In multivariate logistic regression analysis, pleural fluid ADA was negatively correlated 0.62 (0.45-0.85, p = 0.003) with malignancy, whereas serum LDH 1.02 (1.0-1.03, p = 0.004) and serum LDH: pleural fluid ADA ratio 0.94 (0.99-1.0, p = 0.04) was correlated positively with malignant pleural effusion. For serum LDH: pleural fluid ADA ratio, a cut-off level of >20 showed sensitivity, specificity of 0.98 (95 % CI 0.92-0.99) and 0.94 (95 % CI 0.83-0.98), respectively. The positive likelihood ratio was 32.6 (95 % CI 10.7-99.6), while the negative likelihood ratio at this cut-off was 0.03 (95 % CI 0.01-0.15).
  
  
  CONCLUSIONS
  Higher serum LDH and serum LDH: pleural fluid ADA ratio in patients presenting with exudative pleural effusion can distinguish between malignant and non-malignant effusion on the first day of hospitalization. The cut-off level for serum LDH: pleural fluid ADA ratio of >20 is highly predictive of malignancy in patients with exudative pleural effusion (whether lymphocytic or neutrophilic) with high sensitivity and specificity.
authors.affiliation: Department of Respiratory and Critical Care Medicine, Tan Tock Seng Hospital, 11 Jalan Tan Tock Seng, Singapore, 308433, Singapore. akash_verma@ttsh.com.sg.
authors.forename: Akash
authors.initials: A
authors.lastname: Verma
authors.affiliation: Department of Respiratory and Critical Care Medicine, Tan Tock Seng Hospital, 11 Jalan Tan Tock Seng, Singapore, 308433, Singapore.
authors.forename: John
authors.initials: J
authors.lastname: Abisheganaden
authors.affiliation: Pulmonary Disease Program, St. Thomas Hospital and Vanderbilt University, 4220 Harding Rd., Nashville, TN, 37205, USA.
authors.forename: R W
authors.initials: RW
authors.lastname: Light
mesh_terms: D000243:Adenosine Deaminase / Q000378:metabolism*; D002097:C-Reactive Protein / Q000378:metabolism; D005122:Exudates and Transudates / Q000378:metabolism; D006801:Humans; D006836:Hydro-Lyases / Q000097:blood* / Q000378:metabolism; D008175:Lung Neoplasms / Q000150:complications* / Q000378:metabolism; D016066:Pleural Effusion, Malignant / Q000175:diagnosis* / Q000209:etiology / Q000378:metabolism*; D011014:Pneumonia / Q000150:complications / Q000378:metabolism; D012189:Retrospective Studies; D012680:Sensitivity and Specificity; D014397:Tuberculosis, Pulmonary / Q000150:complications / Q000378:metabolism
chemical_list: D002097:C-Reactive Protein; D000243:Adenosine Deaminase; D006836:Hydro-Lyases; C045581:lactate dehydratase
keywords: Adenosine deaminase; Biopsy; Cancer (lung); Lactate dehydrogenase; Pleural effusion