Lumbar Puncture and Cerebrospinal Fluid Exam

This is a procedure in which a small needle is put into the lower portion of the back and a small amount of clear fluid is removed. This is the fluid that surrounds the brain and spinal cord. A pressure is also taken of the spinal fluid. Your caregiver looks at the spinal fluid to determine whether it looks normal. It is then examined under a microscope to search for anything that may look unusual. Some of the unusual things that can be found would be blood in the spinal fluid or an elevation of white blood cells. It also tells what type of cells are present which would help determine if there could be encephalitis or meningitis, and whether the infection would be caused by a germ or a virus. It also reveals other blood chemistries which could indicate other problems present.


No preparation or fasting is necessary.


  • Pressure: less than 20 cm H2O

  • Color: clear and odorless

  • Blood: none

  • Cells: RBC: O

  • WBC: Total

  • Neonate: 0-30 cells/μl

  • 1-5 years: 0-20 cells/ìl

  • 6-18 years: 0-10 cells/ìl

  • Adult: 0-5 cells/ìl

  • Differential

  • Neutrophils: 0%-6%

  • Lymphocytes: 40%-80%

  • Monocytes: 15%-45%

  • Culture and sensitivity: no organisms present

  • Protein: 15-45 mg/dl CSF (up to 70 mg/dl in elderly, adults and children)

  • Protein electrophoresis

  • Prealbumin: 2%-7%

  • Albumin: 56%-76%

  • Alpha1 globulin: 4%-12%

  • Alpha2 globulin: 4%-12%

  • Beta globulin: 8%-18%

  • Gamma globulin: 3%-12%

  • Oligoclonal bands: none

  • IgG: 0-4.5 mg/dl

  • Glucose: 50-75 mg/dl CSF or 60% to 70% of blood glucose level

  • Chloride: 700-750 mg/dl

  • Lactate dehydrogenase (LDH): less than 2-7.2 U/ml

  • Lactic acid: 10-25 mg/dl

  • Cytology: no malignant cells

  • Serology for syphilis: negative

  • Glutamine: 6-15 mg/dl

Ranges for normal findings may vary among different laboratories and hospitals. You should always check with your doctor after having lab work or other tests done to discuss the meaning of your test results and whether your values are considered within normal limits.


Your caregiver will go over the test results with you and discuss the importance and meaning of your results, as well as treatment options and the need for additional tests if necessary.


It is your responsibility to obtain your test results. Ask the lab or department performing the test when and how you will get your results.