Examination of less common body fluids: part 4 -⁠ pericardial fluid (use of laboratory tests)

Overview

Obtaining pericardial fluid for laboratory testing is not entirely common, but with the increasing availability of pericardial fluid during cardiac surgery, the importance of laboratory diagnostics may grow. Preanalytical procedures are identical to those for pleural fluid or ascites testing.

Common biochemical tests include amylase activity (increased in pancreatitis, communication of pseudocysts with the pericardium, or esophageal injury), glucose concentration (decreased in infectious, malignant, and rheumatic effusions), cholesterol and LDH (increased in inflammation and tumors), and triglycerides (increased in chylopericardium).

The section dealing with immunological tests in pericardial effusion primarily evaluates inflammatory biomarkers. IL-6 and IL-8, interferon-γ and MCP-1 in pericardial fluid physiologically reach higher values than in plasma and increase significantly after cardiac surgery, ischemic attacks and pericarditis. IL-6 probably has predictive potential for the development of postoperative atrial fibrillation. Among growth factors, TNF-α, VEGF, endothelin-1, and FGF-2 increase, most commonly in viral infections and from iatrogenic and ischemic causes. Interferon-γ is highly sensitive for tuberculous pericarditis. The combination of inflammatory biomarkers allows for assessment of disease severity and improves prognosis evaluation.

The section on less commonly tested or promising biomarkers includes, for example, tumor markers (AFP, CA 125, CA 15-3, CA 72-4, CEA, CYFRA 21-1, HE-4, PSA, thyroglobulin), GDF-15, metalloproteinases and myeloperoxidase (non-specific markers of inflammation, remodelling and risk of postoperative fibrillation), natriuretic peptides, troponins and myoglobin (risk of perioperative infarction, remodelling, atrial fibrillation). The paper also mentions haematological and microbiological tests.

In summary, pericardial fluid testing can be considered a promising area in which, in addition to common components, new biomarkers can be used to characterize the inflammatory and profibrotic environment, the risk of remodelling, and ischemic disorders.

Keywords:

pericarditis – pericard – pericardial fluid – effusion