Significance of serum - effusion albumin gradient in the differential diagnosis of pleural effusion

Light’s traditional criteria (pleural fluid/serum total protein ratio> 0.5; pleura! fluid/serum LDH ratio> 0.6 and pleural fluid LDH> 200 IU/1) for differentiating between exudative and transudative pleural effusions. Fifty consecutive patients of pleural effusion- 33 male and 17 female, in the age range of 15- 75 years- were studied. For clinical diagnosis of the patients, biochemical tests on serum and pleural effusion fluid were done. The serum- effusion albumin gradient and Light’s criteria were compared. Light’s criteria correct identified all the exudates but misdiagnosed 2 of 5 iransudates (cases of heart failure). By using albumin gradienl of 1.2 g/dl or less to indicate exudale and greaier values lo indicate transudat,. all the patients (35 exudaies and 15 transudates) were correctly diagnosed. Light’s criteria are accurate for identifying exudates but not so much in the case of transudates- The serum- effusion albumin gradient is accurate equally for exudates and transudates. Key words: E.uidatc, transudatc. Light’s criteria, scrum- effusion albumin gradient