This document provides information about cerebrospinal fluid (CSF) examination, including its formation, specimen collection via lumbar puncture, and indications for examination. It describes the typical appearance of normal CSF and how examination of CSF properties like cell count, differential, chemistry, and microbiology can help detect diseases like meningitis, tumors, and demyelinating diseases. Guidelines for examining other body fluids like synovial fluid, pleural fluid, and pericardial fluid are also summarized.

1. 1

2. Cerebrospinal Fluid
 Physiologic system to supply nutrients to
nervous tissue, move metabolic waste &
mechanical barrier to cushion the brain &
spinal cord against trauma
 Produce 500 ml/day
 Ultrafiltration and secretion through the
choroid plexus
 Obtained by lumbar puncture, cisternal
puncture, lateral cervical puncture or
ventricular cannulas
2

3. Formation of Cerebrospinal
Fluid
3

4. 4

5. Specimen Collection
 Routinely by lumbar puncture between
3rd, 4th or 5th vertebrae
 Up to 20 mL CSF may normally be moved
 Collected in 3 sterile tubes:
1. Tube 1: chemical & serologic tests
2. Tube 2: microbiology
3. Tube 3: cell count & differential
 Examination should be performed
immediately (<1 hr)
5

6. Indications
 Indications:
1. Meningeal infection
2. Subarachnoid hemorrhage
3. CNS malignancy
4. Demyelinating disease
Opening Pressure:
90-180 mmH2O
>200 mmH2O→20mL
<90 mmH2O →no withdrawn
6

7. Disease detected by CSF
Examination
 High sensitivity, high specificity
bacterial, TB, fungal meningitis
 High sensitivity, moderate specificity
viral meningitis, subarachnoid hemorrhage
 Moderate sensitivity, high specificity
meningeal malignancy
 Moderate sensitivity, moderate specificity
intracranial hemorrhage, viral encephalitis,
subdural hematoma
7

8. Gross Examination
 Normal CSF:
clear and colorless
viscosity similar to water
 Turbidity
leukocyte >200cells/µL
erithrocyte > 400cells/µL
 Clot formation
traumatic tap, complete spinal block,
suppurative and tuberculous meningitis
8

9. Gross Examination
 Viscous
metastatic mucin-producing
adenomacarcinomas
cryptococcal adenocarcinomas
 Xanthochromia
pink, orange or yellow
due to RBC lysis or Hb breakdown
bilirubin, protein >150mg/dL, carotinoids,
melanin, rifampicin therapi, contamination
of detergent or methiolate disinfectan
9

10. Microscopic Examination
Total Cell Count
 Leukocyte: normal 0-5 cells/µL, neonates <30 cells/µL
 Use Fuch Rosenthal or Neubauer counting chamber
Differential Count
 Performed on a Wright’s-stained smear
 Normal: primarily lymphocytes & monocytes
adult: lymphocytes : monocytes = 70:30
children: monocytes more prevalent (up to 80%)
 Neutrophil: e.g bacterial meningitis
 Lymphocytes: e.g viral & Tb meningitis
 Eosinophil: e.g parasitic & fungal infections
10

11. Chemical Analysis
 Total Protein
Derived from plasma, concentration<1%
blood level (15-45 mg/dL)
elevated CSF protein:
Increased permeability of BBB (meningitis,
hemorrhage)
Decreased resorption at arachnoid villi
Mechanical obstruction (tumor)
Increase intrathecal immunoglobulin
synthesis (Guillain-Barre synd, multiple
sclerosis)
Method: Turbidimetric, colorimetric
11

12. Chemical Analysis
 Glucose
derived from blood glucose
fasting CSF glucose 50-80mg/dL
60% plasma values, normal ratio 0.3-0.9
Hypoglycorrhacia:
bacterial, tuberculous and fungal
meningitis
12

13. Chemical Analysis
Lactate
 Reference: 9.0-26.0 mg/dL
 differentiating viral meningitis from
bacterial, mycoplasma, fungal & TB
meningitis
 Viral meningitis <35 mg/dL
 Bacterial meningitis >35 mg/dL
 Sensitivity & specificity 80-90%
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14. Chemical Analysis
 Enzymes
1. Lactate Dehydrogenase (LDH)
Normal < 40U/L
traumatic tap vs intracranial hemorrhage
elevated in bacterial meningitis
sensitivity & specificity 86% & 93%
2. Creatine Kinase (CK)
Normal < 5 U/L
elevated in demyelinating disease, seizures,
stroke, malignant tumors, meningitis & head injury
14

15. Microbiological Examination
 Gram stain, bacterial antigen test, Limulus
Lysate assay
 Bacterial Meningitis
group B Streptococcus and Gram negative rods
Hemophilus influenza
Neisseria meningitidis & Streptococcus
pneumonia
 Viral meningitis
Enteroviruses (polioviruses)
 Fungal meningitis
Cryptococcus (in AIDS patients)
 Tuberculous meningitis 15

16. Differential Diagnosis of Meningitis
Bacterial Viral Tubercular Fungal
WBC count Elevated
1000-
100,000
Elevated
5-300
Elevated
100-600
Elevated
40-400
Cell present neutrophil Lympho-
cytes
Lympho-
cytes &
monocytes
Lympho-
cytes &
monocytes
Protein
elevated
Marked
80-500
Moderate
30-100
Moderate to
marked
50-300
Moderate to
marked
50-300
Glucosa Decreased
<40mg/dL
normal Decreased<4
5 mg/dL
Normal to
decrease
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Transudates & Exudates
Transudates: case3
increased capillary hydrostatic pressure or decreased
plasma oncotic pressure
 Congestive heart faillure
 Hepatic cirrhosis
 Hypoproteinemia
Exudates: case4
Increase capillary permeability or decreased lymphatic
resorption
 Infections: Tb, bacterial, viral pneumonia
 Neoplasms: metastatic Ca
 Extrapleural sources: pancreatitis, ruptured esophagus

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Light’s Criteria
Exudate: 1/more of following criteria
1. PF/S protein >0.5
2. PF/S LD > 0.6
3. PF LD >2/3 serum upper limit of normal
Sensitivity 98%, specificity 80%

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Gross Examination
Transudates Exudates
Color Pale yellow to
straw
Turbidity Clear Turbid/milky/
bloody
Odor - Fecalent:
anaerobic inf
Clot - +

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Microscopic Examination
Transudates Exudates
Cell counting < 1000/µL > 1000/µL
Differential count :
Mesothelial cell
Neutrophilia (>50%)
Lymphocytosis
(>50%)
Eosinophilic (>10%)
negative
10% case
30% case
Cong heart
failure, trauma
Tb, empiema,
rheumatoid
Bacterial pneu,
pancreatitis
Tb, viral inf,
malignancy, SLE
parasitic/fungal
inf, drug rx,
rheumato

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Chemical Analysis
Transudates Exudates
Protein <3.0 g/dL >3.0 g/dL
Glucose = serum < 60mg/dL :
purulent
LDH PF/S <0.6
<200 IU/L
PF/S >0.6
>200 IU/L
Amylase ≤ serum ≤ serum
pH >7.4 >/<7.3

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Immunologic & Microbiological
Examination
 Immunologic:
1. Rheumatoid Factor
2. ANA titers
3. Complement levels
 Microbiological:
1. Gram’s stain
2. Acid-fast stain
3. culture

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Synovial Fluid
 Viscous liquid found in the joint cavities
 Ultrafiltrate of plasma combined with
hyaluronic acid produced by the synovial
cell
 Normal: < 3.5mL
 Functions:
1. Acts as lubricant and adhesive
2. Provides nutrients for the avascular
articular cartilage

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Synovial Fluid

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Specimen Collection
 Arthrocentesis
 Steril, disposable needles and plastic syringe
 Specimen:
1. EDTA: cell count & diff count
2. Na-Heparinized : chemical & immunologic test
3. Plain: microbiologic test & crystal examination
 Oxalate, Li-heparin and EDTA powder avoided

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Gross Examination
Color
 evaluated in a clear glass tube against a white
background
 Normal: colorless to pale yellow
 noninflammatory/ inflammatory dis: straw to
yellow (xanthochromia)
 Septic: yellow, brown, green

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Clarity
 Related to the number and type of particles
within synovia
 Normal: transparent
 Translucent: leukocytes
 Opaque: massive crystals
 Milky opalescent: abundance of cholesterol
crystal
Gross Examination

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This is the colorless, clear
synovial fluid from a patient with
osteoarthritis accompanied by a
low synovial-fluid white cell count.

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Cloudy but translucent
inflammatory synovial fluid were
taken from a patient with
rheumatoid arthritis (left) and
Gout (right).

32. 32
This bloody fluid with a
thicker layer of lipid
material separated after
centrifugation was
aspirated from a patient
with a tibial fracture into
the joint space.

33. 33
Synovial fluid taken from a
patient with an inflammation
process

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Microscopic Examination
Total Cell Count
 1 hour after arthrocentesis
 Hemacytometer or automated cell counter
 Incubated with hyaluronidase
 Normal: <150-200/ µL

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Differential Count
Normal:
 Neutrophils 20%
 Lymphocytes 15%
 Monocytes & macrophages 65%
 Eosinophilia 2%
Elevated:
 Neutrophils: inflammatory, Gout & RA
 Lymphocytes: early RA, chronic infection
 Monocytes: viral arthritis
 Eosinophilia: RA, metastatic carcinoma, parasitic inf
Microscopic Examination

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Crystal Examination
 Gout: crystal deposition in articular tissue
 1. monosodium urate monohydrate (MSU)
2. calcium pyrophosphate dihydrate (CPPD)
3. apatite
4. basic calcium phosphate (BCP)
 Polarized light microscope
 1. MSU: Gout, septic arthritis
2. CPPD: degenerative arthritis, hypo-Mg,
hemochromatosis
Microscopic Examination

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Synovial Fluid Crystal
Crystal Shape
Monosodium urate Needles
Ca pyrophosphate Rods
cholesterol Notched rhombic
plates
apatite Small needles
corticosteroid Flat, variable
shape plates

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Monosodium urate crystals
Ca pyrophosphate crystals

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Chemical Analysis
 Mucin clot test: add acetic acid
 Glucose: Normal <10 mg/dL
 Protein: Normal 1.38 g/dL
 Lipids:
1. cholesterol-rich psedochylous: chronic RA
2. lipid droplets: trauma
3. chylous effusion: RA, SLE, filariasis,
pancreatitis, trauma

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Immunologic & Microbiological
Examination
1. Immunologic studies
 Rheumatoid Factor (RF)
 Complement
2. Microbiological Examination
 Gram’s stain
 Ziehl-Neelson
 Culture

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Pleural Fluid
 Pleural cavity: between mesothelium of
visceral and parietal pleura
 Normal: small amount of fluid
 Plasma filtrate derived from capillaries of
the parietal pleura, reabsorbed through the
lympatics and venules of the visceral
pleura
 Effusion: accumulation of fluid
 Specimen collection: Thoracentesis
 In EDTA tube: cell counts & differential

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43. 43

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Pericardial Fluid
 Normal: 10-50 mL
 Produced by transudative process
 Effusion: Inflammatory, malignant,
hemorrhagic processes
 Obtained: pericardiotomy,
pericardiocentesis

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Gross Examination
 Normal: pale yellow and clear
 Infection: turbid effusion
 Uremia: clear & straw colored effusion
 Chylous effusion: milky appearance
Microscopic Examination
 Leukocyte count:
>10 000/µL: bacterial, TB, malignant
Pericardial Fluid

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Chemical Analysis
 Protein
>3.0g/dL: exudates
 Glucose
<40mg/dL: bacterial, TB, malignant
 pH
<7.10: rheumatic & purulent condition
7.20-7.40: malignant, uremia, TB
 Enzymes
LD >300U/dL & fluid/serum LD ratio>0.6:
exudates
Pericardial Fluid

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Peritoneal Fluid
 Ultrafiltrate of plasma
 Peritoneal effusion: ascites
 Normal: <50mL
 Paracentesis, Diagnostic Peritoneal
Lavage (DPL), peritoneal dialysis,
peritoneal washing
 Specimen collection:EDTA

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Abdomen symetrically distended secondary to fluid build up in
peritoneal cavity. Skin is also yellowed due to hyperbilirubinemia.

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Gross Examination
 Transudates: pale yellow & clear
 Exudates: cloudy/ turbid
 Acute pancreatitis & cholecystitis: green
 Malignancy & TB: bloody
 Chylous & pseudochylous: milky fluid
Peritoneal Fluid
 Microscopic Examination
 Bacterial peritonitis:
leukocyte >500/µL, >50% neutrophil
 Eosinophilia (>10%): chronic inflammatory process

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Chemical Analysis
 Protein: little value
 Low glucose: TB peritonitis & malignancy
 Elevated amylase: pancreatitis, gastrointestinal
perforation
 Elevated alkaline phosphatase: intestinal
perforation
 Elevated urea/ creatinine: ruptured bladder
Peritoneal Fluid

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References
1. Clinical Diagnosis and Management by
Laboratory Methods.Henry JB. 20th ed. 2001.
WB Saunders co: Philadelphia London
2. Urinalysis and Body Fluid. Strasinger SK. 2nd
ed.1989. F.A. Davis Co: Philadelphia
3. Basic Medical Laboratory Techniques.
Estridge BH, Reynolds AP, Walters NJ. 4th ed.
2000. Delmar: Africa Australia

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