URINE&

BODY FLUIDANALYSIS

CSF ANALYSIS

CONTENTS

INTRO TO CSF

SPECIMEN COLLECTION &

STORAGE

PHYSICAL EXAMINATION

MICROSCOPIC EXAMINATION

BACTERIOLOGIC EXAMINATION

CHEMICAL EXAMINATION

IMMUNOLOGIC EXAMINATION

INTRO TO CSF CNS covered by 3 membranes

[meninges].

Outer most membrane dura mater

Center membrane arachnoid mater (“spider-web like”)

Inner membrane pia mater

CSF between pia and arachnoid maters

• subarachnoid space.

CSF produced by ventricular capillary blood vessels • choroid plexuses

Small volume CSF produced by ependymal cells • line the spaces of the brain and

meningesCSF is a “selective” ultrafiltrate of

plasma.

Total CSF volumes:Adult 85 - 150 mlNeonate 10 - 60 mlAdult Rate of Formation 500 ml/day

Turn over = 20 mL/hour

Action:CNS ProtectionCNS Waste ManagementCNS LubricationCNS Nutrition

CSF VOLUMES & FUNCTION

SPECIMEN COLLECTION

Lumbar puncture : perform in the 3rd and 4th in adult or 4th and 5th interspace in children.

Puncture site may vary if an infection present at preferred site.

Locally infected site must be avoided to prevent introduction of the infection into the CNS.

Procedures :o Cleansing the patient skino Application of local anesthetic.o Spinal needle is advanced into the lumbar interspace, and

often a pop is heard on penetration of the Dura mater.o Physician take the “opening” pressure using the

manometer. Normal pressure for adult : 180 mm Hg.o If CSF pressure is less than or greater than normal, only 1

to 2 ml should be removed.o After CSF has been removed, takes “closing” CSF pressure.o Record both: opening and closing pressure.

SPECIMEN COLLECTION

CSF is collected by lumbar puncture between third, fourth, fifth lumbar vertebrae. It requires certain precautions and careful technique to prevent the introduction of infection or the damaging of neural tissue.

CSF usually collected in three sterile tubes• Label 1 / Tube 1 – used for chemical and serologic

test ( tubes are frozen)

• Label 2 / Tube 2 – used for microbiology lab( room temp.)

• Label 3 / Tube 3 – used for hematology (cell count)

( refrigerated)

Chemistry

Microbiology

Hematology1 23

4Other

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Handling and transportationBacteria• Preferably in trans-isolate medium,

pre-warmed to 25-37°C before inoculation

OR • Transport at ambient temperature

(relevant pathogens do not survive at low temperatures)

Viruses• Transport at 4-8oC (if up to 48hrs or -

70oC for longer duration)

CSF

PHYSICAL EXAMINATION

Parameters Observation InferenceColour Clear, watery and transparent

Red

Dull red / brownish

Yellow (xanthochromic)

Grayish or greenish

Normal

Puncture of blood vessel during collection

Intracranial hemorrhage, cranium fracture

Presence of bile pigments (jaundice), hemorrhage.

Due to infection leading to pus formation

Turbidity Clear / transparent

Hazy / ground glass like

Cloudy / purulent

Red turbid

Normal

Presence of cells/ white clots appearance

Increase in protein / lipid conc. , indicate infection due to presence of WBC.

Puncture of blood vessel during collection

Coagulation No coagulation

Coagulation

Blood (in large quantities)

Normal

Presence of abnormal amount of proteins especially fibrinogen in cases of meningitis

Internal hemorrhage or improper collection.

1

2 34

5

5

1 XANTHACHROMIC CSF

2 RED TURBID CSF

3 DULL RED CSF

4 HAZY CSF

5 CLEAR / NORMAL CSF

MICROSCOPIC EXAMINATION

* Cell counts* Total * Leukocyte* RBC

* Differential * Cytology

DIFFERENTIAL

• Performed on a stained* smear made from CSF.

• It is recommended that stained smears be made even when the total cell count is within normal limits.

• Count 100 cells in consecutive oil-power fields.

• Report percentage of each type of cell present.

Normal CSF Differential Cell Count

MICROBIOLOGY TESTFor positive identification, the microorganism must be

recovered from the fluid by growing it on the appropriate culture medium. Can take 24 hrs I cases of bacterial meningitis to 6 weeks for tubercular meningitis. In many instances, CSF culture is actually a confirmatory test

GRAM STAINIs routinely performed on CSF from all suspected cases of

meningitis although its value lies on the detection of bacterial and fungal organisms.

• Organisms most frequently encountered:• S. pneumoniae (gram positive cocci)• H. influenzae ( pleomorphic gram negative rods)• E. coli (gram negative rods)

MICROBIAL TEST

BACTERIOLOGIC EXAMINATION

• Important in identification of the causative agent in meningitis.• Tests:

• Use second tube because less likely than first tube to contain organism from puncture site.

• Organisms most frequently encountered in Gram Stain: S. pneumoniae (gram positive cocci) H. influenzae ( pleomorphic gram negative rods) E. coli (gram negative rods)

TESTS PURPOSE

GRAM STAIN & INDIAN INK Suspected cases of meningitis Detection of bacterial and fungal organisms

ACID FAST STAIN Identification of tuberculosis meningitis

CSF CULTURE For confirmation

LATEX AGGLUTINATION & ELISA

Latex Agglutination and ELISA provides a rapid means for detecting microorganisms in CSF.

CHEMICAL EXAMINATION

• Protein– 80% plasma

derived• LMW

– Transthyretin (prealbumin)» Albumin

– Transferrin– IgG – very

small amount– 20% intrathecal

synthesis– Reference range• 15 – 45 mg/dL

• Glucose– Need to know

plasma value– Increased• Hyperglycemia• Traumatic tap

– Decreased• Hypoglycemia• Meningitis• Tumors

Albumin and IgG

Albumin not made in CNS

ALB used to address blood-brain barrier integrity

Evaluate CSF/serum ALB indexIndex < 9 = normal9 – 14 minimal

impairment> 100 = not intact

barrier

IgG sourced from inside and outside CNS

ALB used as reference protein to ID intrathecal source of Ig

CSF IgG index = ratio IgGCSF/IgGserum X ALB serum/ALBCSFReference range 0.3 –

0.7• > 0.7 = CNS

sourced• < 0.3 =

compromised BBB

• Normal = 4 bands– ALB– Transthyretin– Transferrin

• b1• t = unique to CSF

– Oligobands ~ multiple sclerosis• Myelin basic

protein– Monitoring

disease progression

ELECTROPHORESIS

CLINICAL SIGNIFICANCE OF ELEVATED PROTEIN VALUES• Elevated total protein values are most

frequently seen in pathologic conditions. Abnormally low values will be present when fluid is leaking from the CNS. Cause of elevated CSF protein include the damage to the blood brain barrier

• Protein fractions• Electrophoreseis• Myelin basic protein

CSF GLUCOSE• Glucose enters the CSF by selective transport across the

blood-brain barrier, which result in a normal value that is approximately 60 – 70 percent that of the plasma glucose. The diagnostic significance of CSF glucose is confined to the finding of values that decreased in relation to plasma values.low CSF glucose can be considerable diagnostic value in determining the causative agents in meningitis.

CSF LACTATE• The determination of CSF lactate levels aid

in the diagnosis and management of meningitis cases. In bacterial, tubercular and fungal meningitis.elevations of CSF lactate greater than 25mg/dl. Destruction of tissue within the CNS owing to oxygen deprivation (hypoxia) causes the production of increaded CSF lactic acid levels.

CSF GLUTAMINE• Glutamine is produced in the CNS by the

brain cells from ammonia and alpha-ketoglutarate. This process serves to remove the toxic metabolic waste product ammonia from the CNS. Normal concentration of ammonia is 8-18 mg/dl. Elevated levelsassociated with liver disorders.

CSF FLUID ENZYMES• CSF enzyme that usually measured are

the lactic dehydrogenase & creatinine kinase isoenzymes.

• The LD isoenzymes appear in CSF following destruction of particular cells, primarily neutrophils, lymphocytes & brain cells.

• Measurement of CK enzymes CK BB in CSF after resuscitation from cardiac arrest-shown to reliably predict recovery when levels are below 17 mg/mL.

IMMUNOLOGIC EXAMINATION

Test Cerebrospinal Fluid Immunoglobulin GIndication Multiple scelerosisPhysiology This immunoglobulin is generally increased in the case of

central nervous system disorders and inflammations.Radial immunodifussion test is performed

Normal range 5-12%Interpretation Panic range-values greater than 12% indicate neurologic

disorders

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