What is the role of pericardial fluid analysis in the workup of pericardial effusion?

Updated: Nov 28, 2018
  • Author: William J Strimel, DO, FACP; Chief Editor: Terrence X O'Brien, MD, MS, FACC  more...
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It should be noted that routine biochemical and cell-count analysis has a low yield in diagnosing the cause of effusion. [15] In contrast, Gram stain and culture can ascertain the etiology convincingly. It is routine for the following tests to be considered part of the standard pericardial fluid analysis:

  • Lactic (acid) dehydrogenase (LDH), total protein - The Light criteria (for exudative pleural effusion) found to be as reliable in distinguishing between exudative and transudative effusions: (1) total protein fluid-to-serum ratio >0.5, (2) LDH fluid-to-serum ratio >0.6, (3) LDH fluid level exceeds two thirds of upper limit of normal serum level [16]

  • Other indicators suggestive of exudate - Specific gravity >1.015, total protein >3.0 mg/dL, LDH >300 U/dL, glucose fluid-to-serum ratio < 1

  • Cell count - Elevated leukocytes (ie, >10,000) with neutrophil predominance suggests bacterial or rheumatic cause, although unreliable

  • Gram stain - Specific (but insensitive) indicator of bacterial infection

  • Cultures - Signal and identify infectious etiology

  • Fluid hematocrit for bloody aspirates - Hemorrhagic fluid hematocrits are usually significantly less than simultaneous peripheral blood hematocrits

  • Cytology of pericardial fluid to assess for the presence of malignant cells

Special tests

These studies of the pericardial fluid should be considered individually based on the pretest probability of the suspected coexisting condition. They include the following:

  • Viral cultures

  • Adenosine deaminase; polymerase chain reaction (PCR); culture for tuberculosis; smear for acid-fast bacilli in suspected tuberculosis infection, especially in patients with HIV

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