Cerebrospinal Fluid Analysis Quiz

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Questions and Answers

What is the primary role of albumin in the cytocentrifuge process?

It prevents the evaluation of abnormal cells.

It reduces cell distortion caused by the centrifugation process. (correct)

It increases the number of cells available for evaluation.

It enhances the visibility of intracellular organisms.

Which type of cell is typically increased following a cerebrovascular accident (CVA)?

Eosinophils

Ependymal cells

Macrophages (correct)

Neutrophils

Which of the following proteins are typically absent in normal cerebrospinal fluid (CSF)?

Fibrinogen (correct)

Albumin

IgM (correct)

Alpha lipoprotein

What does normal cerebrospinal fluid (CSF) typically contain in terms of protein levels?

15-45 mg/dL Signup and view all the answers

What might an elevated CSF protein level indicate?

Meningitis or hemorrhage Signup and view all the answers

Which of the following types of globulins is primarily found as gamma globulin in cerebrospinal fluid (CSF)?

IgG Signup and view all the answers

Which method is preferred for measuring total CSF protein due to its ability to yield consistent results?

Alkaline biuret Signup and view all the answers

What type of cells are classified as 'other' or 'unclassified' in a CSF analysis?

Malignant cells Signup and view all the answers

Which abnormal protein level indicates demyelination in neuron axons?

Myelin Basic Protein Signup and view all the answers

What is the typical CSF glucose level in relation to plasma glucose?

60% to 70% of plasma glucose Signup and view all the answers

Which body fluid is primarily assessed for infectious agents?

Cerebrospinal fluid Signup and view all the answers

What is the main composition determinant of body fluids?

Water and electrolytes Signup and view all the answers

Which body fluid surrounds the unborn fetus during pregnancy?

Amniotic fluid Signup and view all the answers

What type of analysis would involve the examination of cells and crystals in body fluids?

Hematology Signup and view all the answers

Among the following, which is NOT one of the primary types of body fluids?

Cellular fluid Signup and view all the answers

What is the role of immunology in body fluid analysis?

Provides critical information to physicians Signup and view all the answers

Which layer of the meninges is the outermost layer that lines the skull and vertebral canal?

Dura mater Signup and view all the answers

What type of body fluid is classified as transcellular fluid?

Cerebrospinal fluid Signup and view all the answers

Where is cerebrospinal fluid (CSF) produced?

In the choroid plexuses of the ventricles Signup and view all the answers

What is the average production rate of CSF in an adult?

20 mL/hour Signup and view all the answers

Which function is NOT associated with cerebrospinal fluid (CSF)?

Enhance synaptic transmission Signup and view all the answers

What is the typical volume of CSF in an adult?

90-150 mL Signup and view all the answers

Which of the following conditions is an indication for CSF examination?

Encephalitis Signup and view all the answers

What procedure is used to collect CSF?

Lumbar puncture Signup and view all the answers

What substances are commonly found in cerebrospinal fluid?

Water and water-soluble substances Signup and view all the answers

What is the initial step taken before a lumbar puncture procedure?

Measuring intracranial pressure Signup and view all the answers

What is the purpose of collecting CSF into sterile tubes numbered 1, 2, 3, and 4?

To categorize specimens for different types of testing. Signup and view all the answers

What should be done with Tube 1 (chem-sero) if immediate processing is not possible?

Freeze the specimen. Signup and view all the answers

What does xanthochromic appearance in CSF typically indicate?

Increased bilirubin levels. Signup and view all the answers

Which of the following appearances is indicative of increased lipids in CSF?

Milky Signup and view all the answers

What does a clot in the CSF typically indicate?

Traumatic tap or damaged blood-brain barrier. Signup and view all the answers

In a routine CSF analysis, which test is NOT typically performed?

Antibody level testing. Signup and view all the answers

What is the immediate requirement for processing RBCs in a CSF specimen?

Must be processed within 1 hour. Signup and view all the answers

Which statement about the appearance of normal CSF is true?

Normal CSF is crystal clear and colorless. Signup and view all the answers

What is the normal expected range of white blood cells (WBCs) for adults in microliters?

0-5 mononuclear WBCs/µL Signup and view all the answers

When performing a white blood cell count using a hemacytometer, what is the volume of the center small square?

0.004 µL Signup and view all the answers

Which of the following cell types is NOT commonly found in cerebrospinal fluid (CSF) of adults?

Neutrophils Signup and view all the answers

What is pleocytosis characterized by?

Increased white blood cells in body fluid Signup and view all the answers

What is the purpose of using methylene blue staining in WBC counting?

To increase visibility of WBCs Signup and view all the answers

If no dilution is performed, what multiplication factor is used in the WBC counting calculation?

1 Signup and view all the answers

In performing a differential count in CSF, what is the normal predominance of lymphocytes in adults?

28–96% Signup and view all the answers

What is the correct order of steps when preparing slides from concentrated specimens for differential counts?

Spin, remove supernatant, make slides, stain Signup and view all the answers

Study Notes

Body Fluids Analysis

Analysis of body fluids requires multiple laboratory departments
Hematology examines cells and crystals
Clinical chemistry assesses physiologic changes in patients
Microbiology detects infectious agents in nearby body cavities or membranes
Immunology and miscellaneous tests provide critical information to physicians
Pathology consultation may be needed for tumor cells or other abnormalities

Body Fluids Analysis Significance

Studies of body fluids are helpful in assessing inflammation, infection, malignancy, and hemorrhage.

Body Fluid Composition

Key determinants are water and electrolytes
Water enters through consumption of water or food and cellular metabolic processes (approximately 300 mL per day).
Body fluids are subdivided into intracellular (55%) and extracellular (45%). Extracellular fluids are further divided into interstitial fluid and transcellular fluids (in body cavities) and plasma.

Types of Body Fluids

Cerebrospinal fluid (CSF): surrounds brain and spinal cord
Synovial fluid: found around joints
Peritoneal fluid: found in abdominal and pelvic cavities
Pericardial fluid: surrounds the heart
Pleural fluid: surrounds the lungs
Semen fluid: secreted by gonads
Amniotic fluid: surrounds the unborn fetus during pregnancy
Other fluids include sweat, gastric fluid, nasal secretions, saliva, and tears

Cerebrospinal Fluid Anatomy

The brain and spinal cord are lined by meninges (three layers of membranes).
The dura mater is the outer layer, located next to the skull bone, lining the skull and vertebral canal.
The arachnoid mater is the middle layer, a filamentous membrane.
The pia mater is the thin inner membrane lining the brain and spinal cord surfaces, adhering to the brain.
The dura mater layer contains arachnoid villi.
The ventricular system of the brain and the central canal of the spinal cord are lined with special epithelial cells referred to as ependymal cells for production of CSF. CSF is approximately 30% ependymal cells.
Endothelial cells are called choroidal cells that line the choroid plexuses. These cells, along with capillary endothelium, form the blood-brain barrier. This barrier has tight-fitting junctures.
The blood-brain barrier prevents disruptions from diseases such as meningitis and multiple sclerosis from allowing leukocytes, proteins, and chemicals into the CSF.

Blood-Brain Barrier

The tight-fitting endothelial cells prevent filtration of large molecules.
Protects the brain from harmful substances and blocks antibodies and medications.
Restricts entry of large molecules, preventing CSF from resembling ultrafiltrate of the blood.
Approximately 70% of the CSF is formed through a combined process of active secretion and ultrafiltration from plasma. The remaining 30% is formed by ependymal cells in the ventricles and subarachnoid space.

Cerebrospinal Fluid Formation

CSF is produced in the choroid plexuses of the two lateral ventricles, third and fourth ventricles by modified Ependymal cells.
Approximately 20 mL per hour (or 500 mL/day) are produced in adults.
The CSF flows through the subarachnoid space. Adult volume is 90-150 mL; neonate volume is 10-60 mL.
CSF is reabsorbed back into blood capillaries in the arachnoid granulations, maintaining a normal volume at the rate of production itself.

Cerebrospinal Fluid Functions

Provides nutrients to nervous tissue
Removes metabolic wastes
Cushions the brain and spinal cord against trauma
Regulates intracranial volume in response to cerebral vessel changes (adjusting volume).

Indications for CSF Examination

Suspicions of encephalitis, meningitis, multiple sclerosis, and neurosyphilis.
Evaluation of intracranial or subarachnoid hemorrhage.
Patients with unexplained seizures.
Diagnosing malignancies or leukemia
Patients with fever of unknown origin

Cerebrospinal Fluid Composition

CSF contains water and water-soluble substances, such as chloride, CO2, creatinine, glucose, and urea.
These substances diffuse rapidly across the blood-brain barrier.

Specimen Collection and Handling

The procedure to remove CSF is called a lumbar puncture or spinal tap.
Routinely done between the 3rd and 4th or 4th and 5th lumbar vertebrae under sterile conditions.
Intracranial pressure is measured before fluid is withdrawn, and careful technique is used to prevent infection or damage to neural tissue.
CSF volume removed is based on the available volume in the patient (differing between adults and neonates).
Typically, 10-20 mL of CSF is slowly removed into three or four sterile tubes sequentially numbered 1, 2, 3, and 4.

CSF Lab Analysis

Tube 1 is for chemistry/serology
Tube 2 is for microbiology cultures
Tube 3 is for hematology
For immediate processing, tube 1 (chem-sero) is frozen, tube 2 (micro) is kept at room temperature, and tube 3 (hemo) is refrigerated.

CSF Appearance

Normal CSF is crystal clear and colorless.
Descriptive abnormalities include hazy, cloudy, turbid, milky, bloody, and xanthochromic.
Quantification of abnormalities can be slight, moderate, marked, or grossly.
Cloudy specimens may contain increased lipids, proteins, or bacteria.
Clots indicate a traumatic tap.
Milky appearance indicates increased lipids, while oily indicates contamination with x-ray media.

Xanthochromic CSF

Yellowing of the supernatant; may be pinkish or orange.
Common cause is old blood
Other causes include increased bilirubin, carotene, proteins, and melanoma.

CSF Routine Tests

Cell count and differentials
Glucose level
Protein level

CSF Procedures

All specimens should be examined microscopically (hematology).
Stat priority (RBC lyse in 1 hour, WBC in 2 hours). Refrigerate if immediate processing isn't possible.
Electronic counters are usually unusable; manual count is needed.
No dilution is usually required (saline if needed).
Standard Neubauer hemacytometer counting chamber is used.

Formula for Calculations

Results are calculated in number of cells per microliter
Count and record cells from both sides of the hemocytometer.
Average the two sides
Multiply by the dilution factor
Divide by the number of squares counted and the volume of each square (0.1 for large squares; 0.004 for small squares in center #5).
Expected results: 0 RBCs/µL in adults and newborns; WBC count: up to 5 mononuclear in adults, up to 30 in newborns, up to 20 (1-4 yrs), up to 10 (5+ yrs.)

WBC Counts

3% acetic acid can lyse RBCs; Methylene blue staining improves visibility.
Observed in the four corner and center squares of the hemocytometer (both sides). Number is multiplied by the dilution factor to determine WBC per microliter.

Differential Count

Usually performed on cytocentrifuged preparations stained with Wright stain.
Lymphocytes and monocytes are the predominant cells. Neutrophils are not common.
Adults usually have a ratio of lymphocytes to monocytes of 70:30, while children usually have a ratio of 30:70.

Differential Count (Cytocentrifuge)

Specimens are concentrated using centrifugation.
The supernatant fluid is removed, and saved for further tests.
Slides are made from the suspended sediment, air dried, and stained with Wright's stain.

CSF Smear Evaluation

Evaluate the entire smear for abnormal cells, inclusions, clusters of intracellular organisms.
Normal differential values for adults (70% lymphocytes, 30% monocytes); Children/newborns: monocyte.
Other cells include neutrophils; macrophages (increase following CVA); ependymal cells and other normal lining cells.

Other Cells

Eosinophils: often associated with parasitic or fungal infections
Ependymal cells: normal cells unique to CSF, line ventricles, produce CSF.
Suspicious/unclassified or malignant cells should be sent for pathology consultation with a hematologist or pathologist.

CSF Chemistry Tests (Protein)

Normal CSF contains very little protein (15-45 mg/dL) and contains protein fractions similar to serum.
Albumin is the majority of CSF protein; prealbumin follows.
Alpha globulins consist mainly of haptoglobin and ceruloplasmin.
Transferrin is the major beta globulin.
Gamma globulins are mainly IgG; IgA is also present in small amounts.
IgM, fibrinogen, and beta lipoprotein are not usually found in normal CSF.

CSF Protein Values Significance

Decreased levels are not clinically significant.
Elevated levels can indicate blood-brain barrier damage (meningitis, hemorrhage), production of immunoglobulins within the CNS, multiple sclerosis, or neural tissue degeneration.

CSF Methods (Protein)

Turbidity production methods
Dye-binding ability methods (preferred): alkaline biuret, Coomassie brilliant blue--color proportional to protein (Beers Law)
Electrophoresis: looks for oligoclonal bands
Myelin basic protein: evaluates for neuron demyelination (MS) and effectiveness of treatment

CSF Glucose

Normal CSF glucose level is approximately 60-70% of the plasma glucose.
Blood glucose should be drawn 2 hours prior to the spinal tap. STAT procedure.
Glycolysis quickly reduces the CSF glucose level.
Decreased levels can signify bacterial or fungal meningitis, hypoglycemia, brain tumors, leukemias, or disorders causing CNS damage.

CSF Lactate

Normal range is 11-22 mg/dL.
Valuable in diagnosing and managing meningitis cases.
Levels above 35 mg/dL suggest bacterial meningitis; below 25 mg/dL suggests viral meningitis.
Higher levels are associated with hypoxia. Monitor in head injuries. Levels can be falsely elevated with xanthochromia or hemolysis.

CSF Glutamine

Normal range is 8-18 mg/dL.
Increased levels are connected to elevated ammonia (toxin).

CSF Enzymes

Lactate dehydrogenase (LD): 5 isoenzyme types; LD1 and LD2 are in brain tissue.
Creatine kinase (CK): CK3/CK-BB originates from brain tissue.

Major Lab Results for Meningitis Differential Diagnosis

(Clinical Correlations) - Bacterial, Viral, Tubercular, Fungal meningitis

Key elements include WBC, protein, glucose and lactate comparison values (see page 55/56 in original document)

Microbiology Tests

Gram stain: crucial for early bacterial meningitis diagnosis; 10% false negatives possible even with proper technique. Cytospin concentrates specimens, improving sensitivity.
Cultures (aerobic and anaerobic)
Organisms (newborns: E. coli & group B Strep; children: Streptococcus pneumoniae, Hemophilus influenzae, Neisseria meningitidis; adults: Neisseria meningitidis, Streptococcus pneumoniae, Staph. aureus (if shunt)).
Immunocompromised individuals may have Cryptococcus neoformans, Candida albicans, Coccidioides, or any opportunistic organism.

Serologic Testing

VDRL (Veneral Disease Research Laboratory): for neurosyphilis; low sensitivity on CSF, but high specificity.
Fluorescent treponemal antibody absorption (FTA-ABS) test: more sensitive than VDRL.

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Description

Test your knowledge on the properties and analysis of cerebrospinal fluid (CSF). This quiz covers various topics, including protein levels, cellular composition, and indications of abnormalities in CSF following cerebrovascular accidents. Perfect for students and professionals in the medical field!