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Lumbar Puncture (LP) Interpretation of Cerebrospinal Fluid 

  • Author: Gil Z Shlamovitz, MD, FACEP; more...
 
Updated: Aug 21, 2014
 
 

Cerebrospinal Fluid Analysis

This short reference guide provides generic information that may guide initial interpretation of cerebrospinal fluid (CSF) studies but should not be used alone for determination of normal or abnormal results. For further information, see Lumbar Puncture.

The patient’s specific factors (which are beyond the scope of this brief guide), as well as the reference range variability among different laboratories, must be considered by the treating provider when obtaining and interpreting tests.[1]

Caution is warranted in the routine clinical use of existing clinical predictive rules for bacterial meningitis until high diagnostic performance is prospectively validated.[2]

Approximately 90% of immunocompetent patients with culture-proven meningitis have CSF findings characteristic of acute community-acquired bacterial meningitis. Immunocompromised patients and patients with tuberculosis meningitis may present with acellular/low–white blood cell (WBC)–CSF meningitis.[3, 4]

Normal results in adults

See the list below:

  • Appearance: Clear
  • Opening pressure: 10-20 cm H 2 O
  • WBC count: 0-5 cells/µL (< 2 polymorphonucleocytes [PMN]); normal cell counts do not rule out meningitis or any other pathology
  • Glucose level: >60% of serum glucose
  • Protein level: < 45 mg/dL

Consider additional tests: CSF culture, others depending on clinical findings

Bacterial meningitis

See the list below:

  • Appearance: Clear, cloudy, or purulent
  • Opening pressure: Elevated (>25 cm H 2 O)
  • WBC count: >100 cells/µL (>90% PMN); partially treated cases may have as low as 1 WBC/µL
  • Glucose level: Low (< 40% of serum glucose)
  • Protein level: Elevated (>50 mg/dL)

Consider additional tests: CSF Gram stain and cultures, blood cultures, CSF bacterial antigens, CSF polymerase chain reaction (PCR), others depending on clinical findings

Aseptic (viral) meningitis

See the list below:

  • Appearance: Clear
  • Opening pressure: Normal or elevated
  • WBC count: 10-1000 cells/µL (lymph but PMN early)
  • Glucose level: >60% serum glucose (may be low in HSV infection)
  • Protein level: Elevated (>50 mg/dL)

Consider additional tests: CSF Gram stain and cultures, blood cultures, CSF bacterial antigens, CSF PCR (eg, herpes simplex virus [HSV], varicella-zoster virus [VZV]), others depending on clinical findings

Fungal meningitis

See the list below:

  • Appearance: Clear or cloudy
  • Opening pressure: Elevated
  • WBC count: 10-500 cells/µL
  • Glucose level: Low
  • Protein level: Elevated

Consider additional tests: CSF Gram stain and cultures, blood cultures, CSF bacterial antigens, CSF PCR, CSF India ink, others depending on clinical findings

Tuberculosis

See the list below:

  • Appearance: Clear or opaque
  • Opening pressure: Elevated
  • WBC count: 50-500 cells/µL (early PMN then lymph)
  • Glucose level: Low
  • Protein level: Elevated

Consider additional tests: CSF Gram stain and cultures, blood cultures, CSF bacterial antigens, CSF PCR, CSF tuberculosis culture/stain, others depending on clinical findings

Subarachnoid hemorrhage

See the list below:

  • Appearance: Xanthochromia, bloody, or clear
  • Opening pressure: Elevated
  • WBC count: (1 additional WBC per 1000 RBCs is considered normal correction)
  • Glucose level: Normal
  • Protein level: Elevated

Consider additional tests: CSF Gram stain and cultures, others depending on clinical findings

Multiple sclerosis

See the list below:

  • Appearance: Clear
  • Opening pressure: Normal
  • WBC count: 0-20 cells/µL (lymph)
  • Glucose level: Normal
  • Protein level: Mildly elevated (45-75 mg/dL)

Consider additional tests: Oligoclonal band analysis (serum and CSF), others depending on clinical findings

Guillain Barré syndrome

See the list below:

  • Appearance: Clear or xanthochromia
  • Opening pressure: Normal or elevated
  • WBC count: Normal or elevated
  • Glucose level: Normal
  • Protein level: Elevated

Consider additional tests: Others depending on clinical findings

 
Contributor Information and Disclosures
Author

Gil Z Shlamovitz, MD, FACEP Associate Professor of Clinical Emergency Medicine, Keck School of Medicine of the University of Southern California; Chief Medical Information Officer, Keck Medicine of USC

Gil Z Shlamovitz, MD, FACEP is a member of the following medical societies: American College of Emergency Physicians, American Medical Informatics Association

Disclosure: Nothing to disclose.

References
  1. Wright BL, Lai JT, Sinclair AJ. Cerebrospinal fluid and lumbar puncture: a practical review. J Neurol. 2012 Aug. 259(8):1530-45. [Medline].

  2. Kulik DM, Uleryk EM, Maguire JL. Does this child have bacterial meningitis? A systematic review of clinical prediction rules for children with suspected bacterial meningitis. J Emerg Med. 2013 Oct. 45(4):508-19. [Medline].

  3. Brouwer MC, Thwaites GE, Tunkel AR, van de Beek D. Dilemmas in the diagnosis of acute community-acquired bacterial meningitis. Lancet. 2012 Nov 10. 380(9854):1684-92. [Medline].

  4. Conly JM, Ronald AR. Cerebrospinal fluid as a diagnostic body fluid. Am J Med. 1983 Jul 28. 75(1B):102-8. [Medline].

 
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