CSF ANALYSIS INTERPRETATION

Composition of Normal CSF

Protein-15 - 45 mg/dLGlucose-50 - 80 mg/dLUrea- 6.0 - 16 mg/dLUric acid- 0.5 - 3.0 mg/dLCreatinine- 0.6 - 1.2 mg/dLCholesterol- 0.2 - 0.6 mg/dLAmmonia-10 35 g/dL

Composition of Normal CSFSodium-135 150 mEq/LPotassium- 2.6 3.0 mEq/LChloride-115 130 mEq/LMagnesium - 2.4 3.0 mEq/LCells- 0 5 Lymph/L

Characteristics of normal CSFColor - ColorlessPH - 7.28 7.32Appearance- ClearSp. Gravity- 1.003 1.004No clot formation on standingTotal solids - 0.85 1.70 g/dLPO2 - 40 44 mmHg

Diagnosis by CSFHigh sensitivity, high specificityBacterial, TB, and fungal meningitisHigh sensitivity, moderate specificityViral meningitis, SAH, CNS syphilis, abscessModerate sensitivity, high specificityMeningeal malignancyModerate sensitivity, moderate specificityIntracranial hemorrhage, viral encephalitis, subdural hematoma

XanthochromiaPink, orange, or yellow discolorationRBC lysis or hemoglobin breakdownMay be seen within hours of LPPeak intensity at 24 - 36 hoursRBC > 6000/L (SAH, ICH, infarct, traumatic)Oxyhemoglobin, bilirubin, increased proteinCarotinoids, melanin, rifampin therapy

Reference Intervals for CSF

Cell type

Adults(%)

Neonates(%)

Lymphocytes

62

20

Monocytes

36

72

Neutrophils

2

3

Histiocytes

Rare

5

Ependymal

Rare

Rare

Eosinophils

Rare

Rare

Increased Neutrophils in CSFMeningitis (bacterial, early TB, fungal)Other infectionsFollowing seizuresFollowing CNS hemorrhageFollowing CNS infarctReaction to repeated LPForeign materialsMetastatic tumor

Increased Lymphocytes in CSFMeningitis (aseptic, viral, L monocytogenes)Parasitic infectionsDegenerative disordersEncephalopathy due to drugs, GBSOther inflammatory conditionsSarcoidosis, polyneuritis, periarteritis involving the CNS

Increased CSF Total Protein Increased blood-CSF permeabilityMeningitis (bacterial, fungal, TB)Hemorrhage (SAH, ICH)Endocrine disordersMechanical obstruction (tumor, disc, abcess)Neurosypilis, MS, CVD

Causes of decreased CSF glucose

Increased CSF glucose is of no clinical significance.Meningitis-Bacterial, fungal tubercular and syphilitic meningitis. Tumors involving the meninges.Subarachnoid hemorrhage.Cerebral ameobiasis.

Bacterial Meningitis0 - 1m: Group B strept & E. coli (GNR)1m - 5y: H. influenzae5 - 29y: N. meningitidis>29y: S. pneumoniaeListeria monocytogenes common in newborns, elderly, and other immunocompromised hosts

TestAppearancePressureWBC/LProtein mg/dLGlucose mg/dLChlorideNormal CSFClear90 180 mm 0-8 lymph.15-4550-80115-130 mEq/LAcute bacterial meningitisTurbidIncreased1000 -10000100 500< 40DecreasedViral meningitisClearNormal to moderate increase5-300, rarely >1000Normal to mild increasedNormalNormalTubercular meningitisSlightly opaque cobweb formation Increased/ decreased, spinal block100-600 mixed or lymph.50-300 due to spinal blockDecreasedDecreasedFungal meningitisClearIncreased40-400 mixed50-300DecreasedDecreasedAcute syphiliticClearIncreasedAbout 500 lymphIncreased but