CSF ANALYSIS 3

RBC, WBC, TOTAL, DIFF., CELL COUNT. MICROBIOLOGIC SEROLOGIC EXAMINATION

RBC Count Performed when there is:

(1) traumatic tap,

(2) a need for leukocyte correction, and

(3) a need for protein correction.

Total Cell Count are counted in the four corner squares and the center square of the

Improved Neubauer hemocytometer

In total cell count, ____________ is used to load the hemocytometer

Pasteur pipet

Diluent for total cell count

Normal Saline Solution (NSS)

Routinely performed among cell counting for CSF

WBC Count

Normal WBC count: Adult

0 to 5 WBCs/uL

Normal WBC count: Children =

values are higher

Normal WBC count: Neonates =

0 to 30 mononuclear cells/uL

Diluent for WBC count

3% glacial HAc

WBC count stain

Methylene blue

Sample is undiluted and examined using a phase-contrast microscope

Fuchs-Rosenthal Counting Chamber

With 16 large squares and 0.2 mm depth

Fuchs-Rosenthal Counting Chamber

Specimens are concentrated and stained

Differential Count

Differential Count Number of cells counted:

100

Specimen Concentration for differential count

Sedimentation

Filtration

Cytocentrifugatio

causes less cell distortion; not routinely performed

Sedimentation:

causes less cell distortion; not routinely performed

Filtration:

0.1 ml CSF + 1 drop 20% albumin (↑cell yield and ↓distortion) ——→ centrifugation for 5 to minutes ———→ Wright’s staining

Cytocentrifugation

Performed to identify the causative agent in meningitis

MICROBIOLOGIC EXAMINATION

MICROBIOLOGIC EXAMINATION Specimen:

CSF and blood

MICROBIOLOGIC EXAMINATION Specimens should be concentrated by centrifugation at

1500xg for 15 minutes

Duration of incubation: 24 hours

bacterial meningitis

Duration of incubation: 6 weeks

tubercular meningitis

Confirmatory procedure rather than diagnostic

Blood Culture

Routinely performed on CSF from all suspected cases of meningitis

Gram Staining

Recommended method for the detection of organisms

Gram Staining

______ of organism should be present for adequate Gram stain results

10⁵/ml

Organisms most frequently observed Gram (+):

Streptococcus pneumoniae (cocci)

Streptococcus agalactiae (cocci) in newborns

Listeria monocytogenes (bacilli) in newborns

Organisms most frequently observed Gram (-):

Escherichia coli (bacilli)

Neisseria meningitides (cocci)

Haemophilus influenza (pleomorphic bacilli)

Organisms most frequently observed Star burst pattern:

Cryptococcus neoformans

Performed when tubercular meningitis is suspected

Acid Fast/Fluorescent Antibody Stains

Detect the presence of a thickly encapsulated Cryptococcus neoformans

India Ink

More sensitive method in the detection Cryptococcus neoformans in serum and CSF

Reverse Latex Agglutination

Reverse Latex Agglutination Should be confirmed by

culture and India ink

In reverse Latex Agglutination False positive reactions occur mainly due to

rheumatoid factor

Used in combination with hematology and clinical chemistry results

Bacterial Antigen Test

Provide rapid means for detecting and identifying microorganisms in CSF

Latex Agglutination Tests and ELISA

Test kits available for the detection of Streptococcus group B, Haemophilus influenzae type B, Streptococcus pneumoniae, Neisseria meningitidis A, B, C, Y, W135, and Escherichia coli K1 antigens.

Latex Agglutination Tests and ELISA

Diagnosis of meningitis caused by Gram (-) organisms

Limulus Lysate Test

Limulus Lysate Test principle: The ________ produced by the cell walls of Gram (-) organisms will coagulate the _____________ within ___________

endotoxin, amebocyte lysate, 1 hour incubated at 37oC.

Limulus Lysate Test Reagent

Blood cells (amebocyte) of horseshoe crabs (Limulus polyphemus)

Limulus Lysate Test positive color result

Blue

Performed for the diagnosis of neurosyphilis

Venereal Disease Research Laboratories (VDRL)

Most sensitive and specific for syphilis diagnosis

Fluorescent Treponemal Antibody-Absorption

(FTA-ABS)