|
 Introduction
CSF originates from the blood. The choroid
plexes in the 1st , 2nd
and 3rd ventricles of the brain are the sites of CSF production.
CSF is formed from plasma by the filtering and secretary activities of the choroid plexus and lateral ventricles. CSF circulates
around the brain and the spinal cord.
CSF nourishes the tissues of the central nervous system
(CNS) and helps to protect the brain and the spinal cord from injury. It
primarily acts as a water shock absorber. It totally surrounds the brain and
the spinal cord and thus absorbs any blow to the brain. CSF also acts as a
carrier of nutrients and waste products between the blood and the CNS.
Specimen type, collection and storage. Only a physician
or a specially trained nurse must collect the specimen. Laboratory personnel
should be present, however, so that the specimen is delivered to the
laboratory immediately after collection. Spinal puncture isa process
by which a long needle is inserted into the subarachnoid
space between LI and L5 and about 2ml of CSF is withdrawn. The specimen is
then transferred into a clean penicillin vial containing about 8mg of a
mixture of EDTA and sodium fluoride in the ratio of 1:2. Protein estimation
can also be carried out on this specimen.
Glucose and protein estimations should be performed as
soon as possible after drawing the CSF specimen. If testing is delayed, the
specimen may be frozen at -200C up to 3 days. Centrifuge specimens
containing red blood cells or particulate matter.
Do not delay testing the CSF because cells and
trypanosomes are rapidly lysed once the CSF is
removed from the body. Glucose will be rapidly destroyed inthe
absence of preservatives.
Remember: CSF is the most precious biological material. Often,
only small volumes of CSF are available for analysis due to difficulty in
collection. Hence handle this with care.
The specimen may contain virulent organisms. Avoid mouth
pipetting.
|
