<prompt> All the following in the Lights criteria are suggestive of exudative pleural effusion except -Pleural fluid protein : serum protein ratio 0.5Pleural fluid ADA 16Pleural fluid LDH : serum LDH ratio 0.6Pleural fluid L DH two thirds of the upper limitof serum LDH  <response>: Ans. is b i.e.. Pleural fluid ADA 16 Diagnostic criteriao The Lights Criteria Rule is a traditional method of differentiating transudates and exudates that measures serum and pleural fluid protein and LDH.According to the traditional Lights Criteria Rule, if at least one of the following three criteria lie, component tests of the rule is fulfilled, the fluid is defined as an exudate.o Pleural fluid proteinserum protein ratio greater than 0.5. oro Pleural fluid LDHserum LDH ratio greater than 0.6 oro Pleural fluid LDH greater than two-thirds the upper limits of the laboratorys normal serum LDH. 