Sysmex Europe
Sysmex Europe
Other Sites

Body fluids

Body fluid analysis covers several analytical disciplines. This includes counting and differentiating cells and other particles. Counting and differentiating cells in a range of different body fluids, such as cerebrospinal fluid, serous fluids, and synovial fluid is possible with our XN-Series and some of the X-class analysers. Cell counts and differentiation in body fluids is one important aspect in the process of finding the right diagnosis.There are various reasons for requesting this type of analysis, depending strongly on the type of body fluid.

Automating these processes for body fluids has several advantages compared to manual methods using a traditional counting chamber. It is fast and convenient. Its quality does not depend on subjective skills, so it is an appropriate way of standardising the procedure. And the number of time-consuming manual chamber counts can be reduced.

Because of the quick degradation of cells in body fluids, especially neutrophils, one should analyse the sample as quickly as possible.

Cerebrospinal fluid (CSF)

Cerebrospinal fluid is a clear, physiological saline body fluid with low protein content derived from ultrafiltration of the blood. It fills the space between the skull, brain and ventricles and surrounds the spinal cord. It serves as a “cushion“ for the brain and spinal cord, transports hormones andneurotransmitters, helps to remove toxic metabolites and ensures the brain has a constant milieu. A healthy adult usually has around 100 to 150 mL of this special fluid, and daily production is normally around 500 mL.

Cellular analysis of cerebrospinal fluid is requested to detect or exclude diseases affecting the central nervous system: infection by bacteria, viruses, fungi, or protozoans; inflammation, e.g. multiple sclerosis, or Guillain-Barré syndrome; meningeosis, i.e. cells from a peripheral tumour.

Samples are mostly taken by lumbar puncture and occasionally by cisternal puncture. In patients with a ventricular shunt, e.g. after surgery or during treatment of a hydrocephalus, samples can also be obtained from the shunt. Although a routine procedure, CSF sampling still bears some risks and makes CSF a precious material.

Cellular counting and differentiation of cerebrospinal fluid supports to distinguish between different types of diseases. As a rule of thumb, more than 5 white blood cells/µL are considered pathological in adults, while in neonates up to 30 white blood cells/µL can occur in normal samples. An increased number of neutrophils is often indicative for bacterial infection while eosinophilia can support the suspicion of parasitic infection, but can also be due to foreign body reaction. The predominance of mononucleated cells rather hints towards inflammatory processes or neurological disorders.

Pleural fluid

Pleural fluid accumulates between the two pleural layers, the space surrounding the lungs known as the pleural cavity. The normal volume of pleural fluid is no more than 10 mL. Excessive amounts of this fluid (pleural effusion) are considered pathological. There are various reasons for such accumulation that range from congestive heart failure (most frequent reason) to pneumonia, pulmonary emboli or tuberculosis etc.

Cell counting and differentiation of pleural fluid is performed to identify the cause of the pleural effusion and to detect or exclude an infection of the lung or pleura by bacteria, viruses, fungi, or protozoans. Large numbers of neutrophils may, for example, suggest an infection, but even non-infectious pleural effusions may contain considerable white blood cell numbers, although there may be more mononucleated cells in this case. In addition, mesothelial cells are commonly seen, and with an oncological disease one can find cancer cells. If the fluid is bloody, this is most frequently due to cancer invasion.

Peritoneal fluid

Like pleural fluid, peritoneal fluid is considered pathological when it exceeds a certain volume, usually 10 mL. Peritoneal fluid is found in the peritoneal cavity. If the fluid has accumulated in excessive volume, it is known as ascites. In most cases, ascites is due to liver cirrhosis, but it can also occur in cancer, congestive heart failure, and even tuberculosis. Analysis of peritoneal fluid is performed to identify the cause of the presence of the fluid and to detect or exclude peritonitis. High neutrophil counts are normally suggestive of infection, while bloody ascites is most often due to cancer invasion.

Pericardial fluid

Pericardial effusion is an abnormal accumulation of fluid in the pericardial cavity, which normally does not exceed 20-50 mL. It can occur due to pericarditis, viral infections, inflammatory disorders, kidney failure, heart surgery etc. As for the other serous body fluids (pleural fluid, peritoneal fluid), its analysis mostly serves to support the aetiology of its occurrence or to detect or exclude infections.

Synovial fluid

Synovial fluid is a clear, physiological body fluid inside the joint cavity that reduces friction between the articular cartilages during movement. In arthritis and infection there is an increase in volume. The cell count and differentiation can help distinguishing inflammatory from infectious causes of the effusion. Very high white blood cell counts (more than 100,000/μL are possible) with a predominance of neutrophils are suggestive of infection of the joint.

Continuous Ambulatory Peritoneal Dialysis (CAPD) fluid

Continuous ambulatory peritoneal dialysis (CAPD) fluid is not a genuine body fluid because it neither occurs physiologically nor due to the disease itself – it is only due to the treatment of a disease. The CAPD process is an alternative to haemodialysis for patients suffering from kidney diseases. It uses the patient's peritoneum as a membrane across which fluids and substances are removed from the blood by osmosis. The procedure is associated with common infections of the peritoneum. Increased white blood cell counts with a high percentage of neutrophils can indicate peritonitis while eosinophilia is mostly considered a common secondary effect of the foreign body catheter.

Body Fluids

SEED: Synovial fluid

Synovial fluid is a viscous liquid found in the cavities of synovial joints

Learn more about Synovial fluid

SEED: CSF – a material with special requirements

As a material for analysis, cerebrospinal fluid (CSF) requires particular attention at all times

Learn more about CSF

Our Glossary

An alphabetical listing of scientific terms

Explore our Glossary

XN-Series – Tailoring your haematology

Growing your knowledge
Visit our Academy
Enjoy our Media Centre
  • All
  • Documents
  • Podcast
  • Images
  • Videos
See our collection
Find your job