PURPOSE: The first step in the evaluation of patients with pleural effusion is to determine whether it is an exudate or a transudate. The criteria established by Light and colleague have been widely used for more than three decades. Recent studies showed that other parameters can be measured with the same discriminative properties as the Light's criteria. The study aims to compare Light's criteria and Costa's criteria [pleural fluid cholesterol and pleural fluid lactate dehydrogenase (LDH)] in separating pleural fluid into exudate and transudate.
METHODS: This is a prospective study involving thirty six adult patients after signing an informed consent. The pleural fluid was sent to the laboratory for total protein, LDH and cholesterol measurement. Blood extraction was done for total protein and LDH determination. Pleural fluid was labeled exudate if it satisfies at least one of the Light's criteria. It was considered exudate in Costa's criteria if pleural fluid cholesterol is > 45 mg/dL and pleural fluid LDH is > 200 IU/L. The sensitivity and specificity with their corresponding 95% confidence interval, predictive values, likelihood ratios, and correct classification rate were computed.
RESULTS: Majority of the patients enrolled in the study was female (n=20; 52.6%). The mean age was 52 years (sd=16 yrs). The most common cause of pleural effusion was parapneumonic ( n=18; 50%). Other causes include metastasis and tuberculosis. The sensitivity of Costa's criteria in identifying pleural fluid whether its transudate and exudate is 73% (CI =0.58 to 0.89) as compared to Light's criteria. Its specificity is 100%.
CONCLUSION: Costa's criteria has a good sensitivity although lower than the Light's criteria but has a high specificity in separating pleural fluid into transudate or exudate in this study.
CLINICAL IMPLICATIONS: Other parameters may be measured with the same discriminative properties as the Light's criteria but has the advantages of not requiring a simultaneous blood extraction and reducing the chemical tests from four to two, thus, lowering the cost of diagnostic procedure.
DISCLOSURE: Judith Soliano, No Financial Disclosure Information; No Product/Research Disclosure Information