Pleural fluid LDH-Cholesterol and ADA levels: Useful biochemical markers in comparision to Light and #8217;s criteria for more rapid and accurate evaluation of pleural effusion

Abstract

Background: Early and decisive evidence of pleural effusion as transudative or exudative nature is of considerable importance for further diagnostic procedure and therapeutic implication. Aims & Objective: To evaluate the utility of PF LDH-Cholesterol including Triglycerides level and ADA levels and comparing it with Light’s criteria for rapid and accurate evaluation of Pleural effusion mainly exudates. Materials and Methods: Total of 100 cases of Pleural effusion studied from July 2011 to September 2012. All the cases were evaluated by clinical, biochemical, cytological analysis of pleural effusion to diagnose underlying cause and different methods were compared for its diagnostic value, its sensitivity and specificity. Results: Out of all the effusions, 94 were exudative and 6 were transudative in nature. The commonest cause of effusion was tuberculous (58 cases) followed by malignancy (24 cases). 62 patients showed ratio of pleural fluid and serum protein 60 mg/dl. 86.2% of patients with TB and 79.16% of malignancy patients had pleural fluid cholesterol levels > 60 mg/dl with pleural fluid to serum cholesterol ratio of >0.4. Pleural fluid triglyceride levels were >40 mg/dl in 50% of the patients. Pleural fluid LDH levels were 135 ± 37 in transudative effusion while it was 676 ± 414, 559 ± 225 and 678 ± 513 in exudative, tuberculous and malignant effusion respectively. Similarly ratio of pleural fluid to serum LDH was <0.6 in transudative while it was 2.68 ± 3.27, 1.93 ± 1.15 and 1.61 ± 1.13 in exudative, tuberculous and malignant effusion respectively. Pleural fluid ADA levels were 20 ± 17, 53.5 ± 43, 65.48 ± 39.9 and 24.29 ± 24.72 in transudative, exudative, tuberculous and malignant effusions respectively. It was found that the specificity of separating transudate and exudates and positive predictive value was 100% with light’s criteria, pleural fluid LDH levels and pleural fluid to serum LDH ratio. Sensitivity and specificity of ADA in tuberculous effusion is 79.31% and 76.16% respectively. Conclusion: In clinical setting Light’s criteria generally distinguish the exudative from transudative pleural effusion. Current study supports other studies in stating that the alternative criteria like PF LDH-Cholesterol and ADA levels must be considered as a good alternative.