CSF

Diluted fluid: when do you count the 4 corner squares for WBCs?

10 - 100 Count 4 corner squares

The formation of these hemosiderin deposits and hematoidin crystals occurs approximately __ hours following a subarachnoid hemorrhage.

18

What is the approximate volume of spinal fluid in an adult?

90-150 mL

CSF counting guidelines

<10 Count all 9 squares 10 - 100 Count 4 corner squares >100Dilute for nucleated cell count

_____ could also cause the CSF to be xanthochromic

A high serum bilirubin

choroid plexus

A highly vascular portion of the lining of the ventricles that secretes cerebrospinal fluid.

characteristics of malignant cells

Giant cells Multinucleation Cellular crowding Irregular nuclear shapes High nuclear to cytoplasmic ratio (N/C ratio) Vacuolation (sometimes dramatic) that may be seen in both the cytoplasm and the nucleus

Blast cells may be seen in the spinal fluid when cell proliferation in _____ spreads to the central nervous system.

acute leukemia or lymphoma

Bone marrow contamination of CSF:

both immature myeloid cells and erythroid cells may be seen but are not a reflection of the patient's peripheral blood picture

Most CSF originates in the _____ _____

choroid plexus

most analyte reference intervals are different for CSF than they are for plasma. For example, the protein level of normal CSF is dramatically _____ than that of plasma.

lower

Hematologic analysis of CSF samples should be performed within _____ of fluid aspiration. Why?

one hour Both red blood cells (RBCs) and white blood cells (WBCs) have limited stability in CSF because CSF is hypotonic and cells can rapidly lyse.

CSF samples from patients who have suffered a subarachnoid hemorrhage (SAH) may have a _____ supernatant when the sample is centrifuged within one hour following collection

pink- to-yellow-tinged

The hemosiderin deposits, hematoidin crystals, and siderophages may be present in the CSF for _____

several months

Pleocytosis

Increased number of cells in CSF

In an adult, ____ WBC/µL is considered normal. Children will have slightly higher cell counts. Up to __ WBC/µL is within normal limits for newborns. Lymphocytes account for ___% of these cells.

0 - 5 30 60 - 100

_____ are indications that an SAH had occurred sometime prior to collection of the CSF sample.

Macrophages that have phagocytized red blood cells (erythrophages) or hemosiderin (siderophages)

Cerebrospinal fluid has three main functions:

Protect brain and spinal cord from trauma. Supply nutrients to nervous system tissue. Remove waste products from cerebral metabolism.

pellicle

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

Xanthochromia is the result of:

breakdown products of RBCs that are present in the CSF due to the sah

Where does most cerebrospinal fluid (CSF) originate?

choroid plexus

A CSF sample is obtained by a physician usually via

lumbar puncture (usually L3-4)

The nucleated cells seen in normal adult CSF are predominantly

lymphocytes and monocyte/macrophages

The term used to describe the colored supernatant is

xanthochromia