Objectives: The first objective was to assess the diagnostic value of new biochemical criteria proposed to discriminate pleural transudates from exudates and to compare their efficiency with those of Light’s criteria. The second objective of the study was to assess the interstudy variability of the parameters repeatedly determinated in two different groups of patients with pleural effusion. Patients and Methods: We recorded clinical characteristics and final diagnoses and measured pleural fluid (PF) and serum levels of protein, LDH, cholesterol and cholinesterase of 243 patients with pleural effusion. Results: Sixty-one (25%) pleural effusions were transudates and 182 were exudates. The sensitivity (99%) and accuracy (96%) of Light’s criteria were higher than those of the other criteria tested, although the differences with those of the PF LDH-cholesterol combination (96 and 93%) did not show statistical significance. Pleural LDH concentration was the criterion with the highest specificity (95%), being significantly higher (p < 0.05) than that of Light’s criteria. The sensitivity, specificity and accuracy of most criteria tested did not vary when compared with those obtained in a study performed 5 years previously. Conclusions: Light’s criteria remain the criteria of choice for segregating exudates from transudates. Based on cost-efficiency reasons, the PF LDH-cholesterol combination appears as an alternative. Because both sets of criteria misdiagnose a substantial percentage of transudates, exceptions based on good clinical judgment and the complementary use of a more specific criterion, as the PF concentration of LDH, must be considered.

Light RW, Mac Gregor MI, Luchsinger PC, Ball WC: Pleural effusions: The diagnostic separation of transudates and exudates. Ann Intern Med 1972;77:507–513.
Hamm H, Brohan U, Bohmer R, Missmahl HP: Cholesterol in pleural effusions: A diagnostic aid. Chest 1987;92:296–302.
Valdes L, Pose A, Suarez J, et al: Cholesterol: A useful parameter for distinguishing between pleural exudates and transudates. Chest 1991;99:1097–1102.
Roth BJ, O’Meara TF, Cragun WH: The serum-effusion albumin gradient in the evaluation of pleural effusions. Chest 1990;98:546–549.
Burgess LJ, Maritz FJ, Taljaard JJF: Comparative analysis of the biochemical parameters used to distinguish between pleural transudates and exudates. Chest 1995;107:1604–1609.
Romero S, Candela A, Martín C, Hernández L, Trigo C, Gil J: Evaluation of different criteria for the separation of pleural transudates from exudates. Chest 1993;104:399–404.
García-Pachon E, Padilla-Navas I, Sánchez JF, Jiménez B, Custardoy J: PF to serum cholinesterase ratio for the separation of transudates and exudates. Chest 1996;110:97–101.
Costa M, Quiroga T, Cruz E: Measurement of PF cholesterol and lactate dehydrogenase: A simple and accurate set of indicators for separating exudates from transudates. Chest 1995;108:1260–1263.
Romero S, Candela A, Arriero JM: ‘Keep testing the waters’. Chest 1996;110:299.
Heffner JE, Brown LK, Barbieri CA (for the Primary Study Investigators): Diagnostic value of tests that discriminate between exudative and transudative pleural effusions. Chest 1997;111:970–980.
Bartter T: Communications to the editor. Chest 1996;110:300.
Roth BJ: Evaluating PF. Chest 1996;110:7–8.
Peterman TA, Speicher CE: Evaluating pleural effusions. A two stage laboratory approach. JAMA 1984;252:1051–1053.
Light RW: Diagnostic principles in pleural disease. Eur Respir J 1997;10:476–481.
Copyright / Drug Dosage / Disclaimer
Copyright: All rights reserved. No part of this publication may be translated into other languages, reproduced or utilized in any form or by any means, electronic or mechanical, including photocopying, recording, microcopying, or by any information storage and retrieval system, without permission in writing from the publisher.
Drug Dosage: The authors and the publisher have exerted every effort to ensure that drug selection and dosage set forth in this text are in accord with current recommendations and practice at the time of publication. However, in view of ongoing research, changes in government regulations, and the constant flow of information relating to drug therapy and drug reactions, the reader is urged to check the package insert for each drug for any changes in indications and dosage and for added warnings and precautions. This is particularly important when the recommended agent is a new and/or infrequently employed drug.
Disclaimer: The statements, opinions and data contained in this publication are solely those of the individual authors and contributors and not of the publishers and the editor(s). The appearance of advertisements or/and product references in the publication is not a warranty, endorsement, or approval of the products or services advertised or of their effectiveness, quality or safety. The publisher and the editor(s) disclaim responsibility for any injury to persons or property resulting from any ideas, methods, instructions or products referred to in the content or advertisements.
You do not currently have access to this content.