Clinical chemical examination of pleural effusion

Clinical chemistry of pleural effusion is a method of examining the pH value of free liquid in the thoracic cavity, qualitative and quantitative protein, amount of glucose, and amount of lactic acid. pH: The exudate is generally low. When the pH is reduced and the glucose content is decreased, it indicates inflammatory effusion; when the pleural pyogenic infection and effusion caused by esophageal rupture, the effusion pH is <7.0. Tuberculous effusion pH <7.3. The decrease in pH can also be seen in rheumatism, tuberculosis, lupus erythematosus, and the like. The pH of the effusion caused by acute pancreatitis is >7.3, and the pH>7.4 can be seen in the malignant effusion. Basic Information Specialist classification: Respiratory examination classification: chest and ascites examination Applicable gender: whether men and women apply fasting: not fasting Analysis results: Below normal: Normal value: no Above normal: negative: Negative test results suggest that it may be normal. Positive: The positive test results suggest that there may be diseases such as empyema, pleurisy, tuberculosis, and pulmonary infarction. Tips: Pay attention to normal eating habits and pay attention to personal hygiene. Normal value Healthy adult pleural fluid below 20ml, mainly in the pleural cavity for lubrication, negative in the normal range. Clinical significance In pathological conditions, such as increased cistern capillary hydrostatic pressure or decreased colloid osmotic pressure, or increased intrathoracic negative pressure and pleural effusion pressure in the pleural fluid, can lead to excessive production of pleural fluid and significant reduction in absorption, resulting in pathological Pleural effusion (pleuraleffusion), also known as pleural effusion. Common causes are pleural or adjacent tissue infections, primary or metastatic tumors. In addition to traditional cytology, biochemistry, and microbiological examination, pleural effusion examinations have been developed to apply immunological and molecular biological methods to further distinguish the nature of effusions. Abnormal results of empyema, pleurisy, tuberculosis, pulmonary infarction, chest metastases or primary malignant tumors, fungal infections, lupus pleurisy, chylothorax, esophageal perforation, uremic pleural effusion. The people who need to be examined have the above-mentioned patients with pleural effusion, such as empyema, pleurisy, tuberculosis, and pulmonary infarction. Positive results may be diseases: pleurisy, tuberculosis, primary exudative lymphoma, tuberculous pleurisy considerations Forbidden before examination: Pay attention to normal eating habits and pay attention to personal hygiene. Requirements for inspection: Actively cooperate with the doctor. Pleural effusion specimen collection was obtained by thoracentesis. Immediately after the specimen is taken, it should be sent for inspection to prevent cell degeneration, destruction or clot formation and affect the result. Inspection process 1. pH: The exudate is generally low. When the pH is reduced and the glucose content is decreased, it indicates inflammatory effusion; when the pleural pyogenic infection and effusion caused by esophageal rupture, the effusion pH is <7.0. Tuberculous effusion pH <7.3. The decrease in pH can also be seen in rheumatism, tuberculosis, lupus erythematosus, and the like. The pH of the effusion caused by acute pancreatitis is >7.3, and the pH>7.4 can be seen in the malignant effusion. 2, protein qualitative and quantitative: in the thoracic inflammatory response, serosal epithelial cells stimulate the amount of mucin secreted by the inflammatory response, mucin qualitative test (rivaltatest) positive. Generally, non-inflammatory fluids (leakage) are mostly negative. The protein content of the exudate often exceeds 30g/L; the leakage is often less than 30g/L, mainly albumin, and the mucin qualitative test is negative. 3. Glucose quantification: The glucose content in physiological pleural effusion is similar to serum. If there is a decrease in glucose in the effusion (<3.35mmol/L, or effusion content/blood content <0.5), it is generally found in rheumatic effusion. , empyema, malignant neoplasms, tuberculous effusion, lupus effusion or esophageal rupture, etc., purulent effusion is more common. 4, lactic acid quantification: lactic acid content determination in pleural effusion helps the differential diagnosis of bacterial infection and non-bacterial infection effusion, when lactic acid up to 6mmol / L or more, should be highly prompted bacterial infection, especially in the application of antibiotics The pleural effusion after treatment is more valuable when the general bacterial test is negative. In the effusion caused by rheumatoid disease, congestive heart failure and malignant tumors, the lactic acid content also showed a slight increase. 5. Determination of lipids: If the chyle-like effusion is still turbid after centrifugation, the triglyceride content is increased (>4.52mmo1/L), the cholesterol content is not high, and Sudan III is dyed red, which is chyle effusion. Found in the rupture of the thoracic duct. If the chyle-like effusion cholesterol is increased (>2.59mmo1/L), the triglyceride is normal, which is cholesterol pleural effusion, found in old tuberculous pleurisy, malignant pleural effusion, cirrhosis, rheumatoid arthritis. 6, enzyme assay (1) Lactate dehydrogenase (LD) activity: The effusion LD>200U/L or the ratio of serum LD to more than 0.6 can be used as an indicator for the diagnosis of thoracic exudate. In the exudate, the LD activity of the suppurative effusion was the highest, followed by the malignant effusion. The LD activity of pleural effusion is proportional to the degree of pleurisy. The decrease of LD activity suggests that the inflammation subsides, while the increase of LD activity indicates that the condition is worse. (2) adenosine deaminase (ADA): ADA activity was significantly increased in tuberculous effusion; ADA level in cancerous effusion was lower, and leakage was the lowest. Such as ADA> 40U / L, even higher than 100U / L, mostly tuberculous effusion, common in tuberculous pleurisy. When treated with anti-tuberculosis drugs, the ADA in the pleural effusion also decreases, so it can also be used as an indicator of the efficacy of anti-tuberculosis treatment. (3) Amylase (AMY): AMY can leak into pleural effusion in acute pancreatitis with pleural effusion, and often higher than serum activity, which is especially important for the differential diagnosis of patients with severe chest pain and dyspnea. Not suitable for the crowd The examination was small and there were no specific contraindications. Adverse reactions and risks Risk of infection: If you use an unclean needle, you may be at risk of infection.