CSF - Analysis with VDRL Test

Cerebral spinal fluid is a clear fluid that provides nutrition to our central nervous system (CNS), which contains both the brain and the spinal cord. CSF analysis is used to examine disturbing conditions occurring inside our brain and spine. A sample of cerebrospinal fluid is taken for the test. This fluid is produced in the brain by a group of cells known as choroid plexus, which is then reabsorbed in the bloodstream and replaced every few hours. This test mainly looks for the signs of neurosyphilis in the CSF, which is usually aggravated by HIV or AIDS.

A CSF analysis is performed with the help of a lumbar puncture in the lower back which is commonly known as the spinal tap. An analysis involves examination of the following:

• Fluid pressure
• Glucose
• Red blood cells
• White blood cells
• Proteins
• Chemicals
• Other invasive organisms like viruses or bacteria

The Venereal disease research laboratory (VDRL) test is a type of non-treponemal micro-flocculation test which is used for screening of syphilis. As mentioned above in the procedure, the flocculation caused by both the specimens is observed under the microscope in the laboratory and the results are obtained as follows:
• Reactive flocculation is seen when large or small aggregates are formed in the center or on the periphery of the reaction circle. This proves the test to be positive and indicates the presence of syphilis.
• Non-reactive flocculation is indicated by a smooth and a light grey suspension with no aggregates formed. This proves the test to be negative indicating the absence of syphilis.

• All the VDRL suspension samples are kept at room temperature.
• A drop of the test specimen needs to be pipette and then it is drawn on the slide.
• To the pipetted test specimen, one drop of VDRL antigen is added.
• After few minutes, both the specimens are mixed thoroughly until a reaction circle is formed.
• The slide is then rotated either manually or on a mechanical rotor at 180 r.p.m.
• Approximately after 8 minutes, flocculation is observed with the help of a microscope.