The page below is a sample from the LabCE course Cerebrospinal Fluid. Access the complete course and earn ASCLS P.A.C.E.-approved continuing education credits by subscribing online.

Learn more about Cerebrospinal Fluid (online CE course) »
How to Subscribe
MLS & MLT Comprehensive CE Package
Includes 94 CE courses, most popular
$95 Add to cart
Pick Your Courses
Up to 8 CE hours
$50 Add to cart
Individual course$20 Add to cart


Clot formation is always abnormal and is often due to increased levels of protein, especially fibrinogen. When the protein level is 1000 mg/dL, clot formation will most likely occur. However, clots may also form at protein levels below 1000 mg/dL.

Some clots may be very fine and appear as a thin membrane or "scum" on the surface of the CSF specimen. This type of clot is referred to as a pellicle. Pellicles are composed of fibrinogen and white blood cells.

The type of clot formed may give some specific information about the disease state. Some examples are provided in the following table:

Example of ConditionType of Clot
Bacterial meningitis Pellicle forms in a short time; large clot formation follows
TB meningitis Web-like clot (pellicle) after 12-24 hours (enhanced by refrigeration)
Paresis (type of neurosyphilis) Incomplete clot
Blockage of CSF circulation Completely clotted due to presence of high levels of protein