Analysis of the liquor

Liquor (cerebrospinal fluid) is formed in the ventricles of the brain by the sweating of blood plasma through the walls of the vessels, and is also secreted by the cells of the vascular plexuses. From the ventricles, it enters the cisterns of the brain and the subarachnoid space. From 400 to 600 ml of liquor is formed per day.

The study (analysis) of cerebrospinal fluid has an important diagnostic value in diseases of the central nervous system and meninges, such as encephalitis (inflammation of the brain), meningitis (inflammation of the meninges), arachnoiditis (inflammation of the arachnoid membrane), syphilis of the brain, cerebrovascular accidents, tumors, and injuries.

General clinical examination of cerebrospinal fluid includes a study of its physicochemical properties and cellular composition.

Reference indicators (norm) of cerebrospinal fluid

Characteristics	Indicators
Color	Colorless
Transparency	Complete
Density:
At lumbar puncture	1,006-1,007
During ventricular puncture	1,002-1,004
Reaction	Weakly alkaline
Protein:
At lumbar puncture	0.2-0.3 g/l
During ventricular puncture	0.1-0.22 g/l
Globulin reactions:
Pandy's reaction	Negative
Nonet-Apelt reaction	Negative
Glucose:
At lumbar puncture	2.8-3.9 mmol/l
During ventricular puncture	2.8-3.9 mmol/l
Chlorides:
At lumbar puncture	120-130 mmol/l
During ventricular puncture	120-130 mmol/l
Cytosis:
At lumbar puncture	7-10 cells/3 µl (2-3×10 6 /l)
During ventricular puncture	0-3 cells/3 µl (0-1×10 6 /l)
Study of native and stained preparations	Neutrophils - 2-4%, lymphocytes - 60±20%, monocytes - 30±10%, eosinophils and ependymocytes - rare

Bacterioscopic examination of cerebrospinal fluid

Bacterioscopic examination with staining of smears from the cerebrospinal fluid sediment according to Ziehl-Neelsen is carried out if tuberculous meningitis is suspected. Smears are prepared from the cerebrospinal fluid sediment after centrifugation and from the fibrinous film formed during fibrin coagulation, in which mycobacteria tuberculosis are captured. The prepared smears are stained according to Ziehl-Neelsen. Mycobacteria tuberculosis are more often detected in fresh cases of the disease (in 80% of patients with tuberculous meningitis). In case of negative or questionable results, bacteriological examination is necessary.

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