title: Platelet-lymphocyte ratios: a potential marker for pulmonary tuberculosis diagnosis in COPD patients.
abstract: BACKGROUND
  In recent decades, morbidity and mortality have been found to be significantly increased in patients with chronic obstructive pulmonary disease (COPD) complicated with pulmonary tuberculosis (PTB). Platelet-lymphocyte ratio (PLR) is an indicator for inflammatory diseases. This study aims to investigate whether PLR could act as a potential marker for patients with COPD complicated with PTB.
  
  
  METHODS
  In this retrospective study, laboratory characteristics of 87 COPD patients complicated with PTB (determined byMycobacterium tuberculosispositive culture from sputum or bronchial lavage fluid) and 83 COPD patients (as the control group, determined byM. tuberculosisculture negativity from sputum or bronchial lavage fluid) were investigated. Data obtained on the day of admission were analyzed.
  
  
  RESULTS
  PLR >216.82 was identified as the optimal cutoff value for discriminating COPD patients with PTB (sensitivity 92.4%, specificity 84.5%, positive-predictive value 91.6%, negative-predictive value 86.2%, and area under the curve [AUC] was 0.87) from patients with COPD alone. The AUC of PLR was significantly greater than that of neutrophil-lymphocyte count ratio (AUC, 0.74; 95% confidence interval, 0.67-0.81;P<0.01).
  
  
  CONCLUSIONS
  PLR could be developed as a valuable maker for identifying tuberculosis infection in COPD patients.
authors.affiliation: Department of Respiratory Medicine, Yiwu Central Hospital, Yiwu, Zhejiang Province, People's Republic of China.
authors.forename: Guozhong
authors.initials: G
authors.lastname: Chen
authors.affiliation: Department of Respiratory Medicine, Yiwu Central Hospital, Yiwu, Zhejiang Province, People's Republic of China.
authors.forename: Chunling
authors.initials: C
authors.lastname: Wu
authors.affiliation: Department of Respiratory Medicine, Yiwu Central Hospital, Yiwu, Zhejiang Province, People's Republic of China.
authors.forename: Zhiying
authors.initials: Z
authors.lastname: Luo
authors.affiliation: Department of Respiratory Medicine, Yiwu Central Hospital, Yiwu, Zhejiang Province, People's Republic of China.
authors.forename: Yiming
authors.initials: Y
authors.lastname: Teng
authors.affiliation: Department of Respiratory Medicine, Yiwu Central Hospital, Yiwu, Zhejiang Province, People's Republic of China.
authors.forename: Suping
authors.initials: S
authors.lastname: Mao
mesh_terms: D000368:Aged; D019540:Area Under Curve; D001792:Blood Platelets; D005260:Female; D006801:Humans; D018655:Lymphocyte Count; D008214:Lymphocytes; D008297:Male; D008875:Middle Aged; D010976:Platelet Count; D011237:Predictive Value of Tests; D029424:Pulmonary Disease, Chronic Obstructive / Q000150:complications* / Q000175:diagnosis; D012372:ROC Curve; D015203:Reproducibility of Results; D012189:Retrospective Studies; D014397:Tuberculosis, Pulmonary / Q000097:blood* / Q000150:complications / Q000175:diagnosis*
keywords: chronic obstructive pulmonary disease; platelet to lymphocyte ratio; pulmonary tuberculosis