February 1984

Lactic Acid Pleural Fluid Dehydrogenase

Author Affiliations

Winnipeg, Manitoba

Arch Intern Med. 1984;144(2):414. doi:10.1001/archinte.1984.00350140248040

This article is only available in the PDF format. Download the PDF to view the article, as well as its associated figures and tables.


To the Editor.  —In the July issue of the Archives, Brown et al1 describe a patient with hypothyroidism and bilateral pleural effusions. However, their statement that the pleural fluid lactic acid dehydrogenase (LDH) level was normal is curious.There is no such thing as a "normal" or "abnormal" pleural fluid LDH level. Pleural fluid LDH is useful in distinguishing exudates from transudates. A pleural fluid/serum LDH ratio greater than 0.6 suggests an exudate, whereas the ratio is usually less than 0.6 in a transudate.2 Similarly, a pleural fluid LDH level greater than 67% of the upper limit of the normal level for serum LDH suggests an exudate. An LDH level greater than 1,000 IU/L in a parapneumonic effusion suggests that the effusion is infected.3

First Page Preview View Large
First page PDF preview
First page PDF preview