Cerebrospinal Fluid Analysis


CSF analysis, lumbar puncture with analysis of CSF, spinal tap.

To assist in the differential diagnosis of infection or hemorrhage of the brain. Also used in the evaluation of other conditions with significant neuromuscular effects, such as multiple sclerosis.

Patient Preparation
There are no food, fluid, activity, or medication restrictions unless by medical direction.

Normal Findings
Method: Macroscopic evaluation of appearance; spectrophotometry for glucose, lactic acid, and protein; immunoassay for myelin basic protein; nephelometry for immunoglobulin G (IgG); electrophoresis for oligoclonal banding; Gram stain, India ink preparation, and culture or polymerase chain reaction (PCR) for microbiology; microscopic examination of fluid for cell count; flocculation for Venereal Disease Research Laboratory (VDRL).

Lumbar PunctureConventional UnitsSI Units
Color and appearanceCrystal clear
Protein(Conventional Units × 10)
  0–1 moLess than 150 mg/dLLess than 1,500 mg/L
  1–6 mo30–100 mg/dL300–1,000 mg/L
  7 mo–adult15–45 mg/dL150–450 mg/L
  Older adult15–60 mg/dL150–600 mg/L
Glucose(Conventional Units × 0.0555)
  Infant or child60–80 mg/dL3.3–4.4 mmol/L
  Adult/older adult40–70 mg/dL2.2–3.9 mmol/L
Lactic acid(Conventional Units × 0.111)
  Neonate10–60 mg/dL1.1–6.7 mmol/L
  3–10 d10–40 mg/dL1.1–4.4 mmol/L
  AdultLess than 25.2 mg/dLLess than 2.8 mmol/L
IgG(Conventional Units × 10)
Less than 3.4 mg/dLLess than 34 mg/L
Myelin basic protein(Conventional Units × 1)
Less than 4 ng/mLLess than 4 mcg/L
Oligoclonal bandsAbsentAbsent
Gram stainNegativeNegative
India inkNegativeNegative
CultureNo growthNo growth
RBC count00
WBC count(Conventional Units × 1)
Neonate–1 mo0–30/microL0–30/mm3
  1 mo–1 yr0–10/microL0–10/mm3
  1–5 yr0–8/microL0–8/mm3
  5 yr–adult0–5/microL0–5/mm3
CytologyNo abnormal cells seenNo abnormal cells seen
RBC = red blood cell; VDRL = Venereal Disease Research Laboratory; WBC = white blood cell.CSF glucose should be 60%–70% of plasma glucose level.Color should be assessed after sample is centrifuged.
WBC DifferentialAdultChildren

Critical Findings and Potential Interventions

  • Positive Gram stain, India ink preparation, or culture
  • Presence of malignant cells or blasts
  • Elevated WBC count
  • Adults: Glucose less than 37 mg/dL (SI: Less than 2.1 mmol/L); greater than 440 mg/dL (SI: Greater than 24.4 mmol/L)
  • Children: Glucose less than 31 mg/dL (SI: Less than 1.7 mmol/L); greater than 440 mg/dL (SI: Greater than 24.4 mmol/L)

Timely notification to the requesting health-care provider (HCP) of any critical findings and related symptoms is a role expectation of the professional nurse. A listing of these findings varies among facilities.

Important signs to note include allergic or other reaction to the anesthesia, bleeding or CSF drainage at the puncture sight, changes in level of consciousness, changes to or inequality of pupil size, or respiratory failure.

Specific infectious organisms are required to be reported to local, state, and national departments of health. Lists of specific organisms may vary among facilities. State health departments provide information regarding reportable diseases, which can be accessed at each state health department Web site. The CDC provides information regarding national notifiable diseases at https://ndc.services.cdc.gov/search-results-year/.

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