What Is an Exudate?

Exudate, mostly dark yellow turbid, bloody, purulent, with a specific gravity often greater than 1.018. Exudate is easy to coagulate because it contains fibrinogen and thromboplastin released by tissues and cells.

Exudate

Exudate, mostly dark yellow turbid, bloody, purulent, with a specific gravity often greater than 1.018. Exudate is easy to coagulate because it contains fibrinogen and thromboplastin released by tissues and cells.

Under normal circumstances, the cavity contains a small amount of liquid that acts as a lubricant. When the pathological condition increases, the fluid in the cavity increases, and the effusion occurs, which is called serous cavity effusion. Divided by the nature of the effusion

Exudate

The appearance of exudate is mostly dark yellow, cloudy, bloody, and purulent; the specific gravity is often greater than 1.018. Exudate is easy to coagulate because it contains fibrinogen and thromboplastin released by tissues and cells.

1. colour:

1. Total number of cells:

Pleural fluid bacteriological examination

Exudative pleural fluid of unknown origin should be treated with gram and acid-fast staining smears, while bacterial (aerobic, anaerobic), mycobacterial and fungal cultures should be performed. For bacterial culture, the pleural fluid should be inoculated directly on the medium at the bedside. Applying the BACTEC system at the bedside for mycobacterium inoculation culture has a high positive rate and a shorter time required.

Pleural fluid biochemical examination

1. Protein quantitative test:

1. Analysis of T lymphocyte subsets: T cell content, CD3, CD4 cell percentage and absolute numbers in tuberculous pleural fluid were significantly higher than those in peripheral blood; while absolute numbers of CD3, CD4 and CD8 cells and CD8 cell percentage in malignant pleural fluid were significantly lower In peripheral blood.

2. Pleural fluid chromosome examination: In malignant pleural fluid, the cell chromosomes are mainly hyperdiploid and polyploid, most of which are aneuploid, and often accompanied by special morphological chromosomes such as giant chromosomes, linear chromosomes, and minichromosomes Wait. The diagnosis rate of malignant pleural fluid can reach 81% if the diagnosis of 10% hyperdiploidy occurs.

3 Polymerase chain reaction (PCR) and nucleic acid probe technology: PCR technology is an efficient in vitro DNA amplification technology that can be used to detect pathogenic microorganisms that are difficult to grow and grow in vitro, such as Mycobacterium tuberculosis, so the diagnosis of tuberculous pleurisy is very Significant.

Attachment: diagnostic criteria for leakage and exudate

In general, clarifying the nature of pleural fluid leakage is the basis for determining the cause of pleural fluid. The previous criteria for distinguishing the two include the specific gravity of pleural fluid, cell number, protein quantification, and mucin quantification (Rivalta test). It also contradicts the emergence of so-called pleural fluid, which makes it difficult to determine the cause of pleural fluid clinically.

A common indicator that distinguishes leaked fluid and exudate is the determination of protein and LDH content in pleural fluid, the Light standard. After 30 years of clinical application, the sensitivity and specificity of the standard are greater than 99%. Light standards are as follows: Exudates that meet one or more of the following standards:

The ratio of pleural fluid protein to serum protein is greater than 0.5;

The ratio of pleural fluid LDH to serum LDH is greater than 0.6;

LDH in pleural fluid is greater than 2/3 of the upper limit of normal serum LDH.

The main problem with the Light standard is that some of the leakage caused by CHF may also meet the exudate standard. Therefore, if the pleural fluid caused by CHF meets the exudate standard, the serum and pleural albumin levels should be measured at the same time. If the difference between serum and pleural albumin is greater than 1.2g / dl, leakage is still considered.