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Cerebrospinal Fluid (CSF) Chemical Tests

Fluid CSF

Test Codes

Glucose, CSF: EPIC: LAB5268, Beaker: GLCSF, Lactate Dehydrogenase (LD), CSF: EPIC: LAB5081, Beaker: LDCSF, Lactic Acid, CSF: EPIC: LAB5079, Beaker: LACSF, Protein, CSF: EPIC: LAB5109, Beaker: PRCSF

Department

Chemistry

Instructions

Cerebrospinal Fluid (CSF) Chemical Test is available for the following analytes: Glucose, Lactate Dehydrogenase (LD)*, Lactic Acid*, and Protein. This testing is not a panel and analytes are ordered individually. Testing of fluid analytes or sources not listed in the Lab Test Directory must be approved by a Medical Director. Please contact the Laboratory for more information.

*Not performed at Farmington Hills or Grosse Pointe.

Specimen Collection Criteria

Collect: Cerebrospinal fluid (CSF) in CSF Collection Tube #1. (Minimum: 2.0 mL)

• For more information, please see the Specimen Collection Manual: CSF.
• Send specimen for processing immediately after collection.

Physician Office/Draw Specimen Preparation

Refrigerate (2-8°C or 36-46°F) specimen immediately after collection and maintain refrigerated prior to transport. If LD, CSF is ordered, a separate aliquot maintained at room temperature (20-26°C or 68-78.8°F) is preferred.

Preparation for Courier Transport

Transport: CSF in Collection Tube #1, refrigerated (2-8°C or 36-46°F). If LD, CSF is ordered, a separate aliquot at room temperature (20-26°C or 68-78.8°F) is preferred.

Rejection Criteria

• Specimens grossly contaminated with blood.
• Specimens collected in a container or tube with an additive.

Inpatient Specimen Preparation

Transport specimen STAT, on wet ice, to the STAT Laboratory (Royal Oak) or to the Chemistry Laboratory (Canton, Dearborn, Farmington Hills, Grosse Pointe, Taylor, Trenton, Troy and Wayne).

In-Lab Processing

Before chemistry testing, centrifuge to remove cellular material.

Storage

Specimen Stability for Testing:

Room Temperature (20-26°C or 68-78.8°F): Unacceptable (7 days for LD, CSF)
Refrigerated (2-8°C or 36-46°F): 7 days
Frozen (-20°C/-4°F or below): Undetermined

Specimen Storage in Department Prior to Disposal:

Refrigerated (2-8°C or 36-46°F): 30 days*

*Add-on testing for LD, CSF is not available on specimens that have been refrigerated or frozen. 

Laboratory

Canton Chemistry Laboratory
Dearborn Chemistry Laboratory
Farmington Hills Chemistry Laboratory 
Grosse Pointe Chemistry Laboratory 
Royal Oak STAT Laboratory 
Taylor Chemistry Laboratory
Trenton Chemistry Laboratory
Troy Chemistry Laboratory
Wayne Chemistry Laboratory 

Performed

Sunday – Saturday, 24 hours a day.
STAT results available within 1 hour of receipt in the Laboratory.
Routine results available within 4 hours of hours of receipt in the Laboratory.

Reference Range

Glucose, CSF: 50-80 mg/dL.
Lactic Acid, CSF: 0.5-2.0 mmol/L.
LD, CSF: 5-30 U/L.
Protein, CSF: 15-45 mg/dL.

Test Methodology

Spectrophotometry, Enzymatic Spectrophotometry.

Interpretation

• A fasting CSF glucose is usually 50-80 mg/dL (about 60% of plasma glucose). CSF glucose below 40 mg/dL or having a ratio of CSF glucose/plasma glucose of less than 0.3 is considered abnormal. Low glucose in CSF is seen with bacterial, tuberculous, and fungal meningitis. Low glucose may also be seen in other disorders, e.g., viral infection, malignancy, and rheumatoid meningitis.
• Elevated lactate levels in CSF reflect CNS anaerobic metabolism due to tissue hypoxia. Lactic acid levels in CSF are also elevated (typically greater than 3.9 mmol/L) in bacterial meningitis. CSF and blood lactate levels are largely independent of each other.
• LD level in CSF may be helpful in distinguishing a traumatic tap from intracranial hemorrhage. A traumatic tap with intact RBCs is not usually associated with an increased LD. LD is higher in bacterial meningitis than in aseptic meningitis. LD may also be elevated in CNS leukemia, lymphoma, and metastatic carcinoma.
• Increased total protein in CSF is found with bacterial meningitis, tuberculous meningitis, brain abscess, meningovascular syphilis, diabetes mellitus, CVA, subarachnoid hemorrhage, some cases of multiple sclerosis, encephalomyelitis, other degenerative processes causing neurologic disease, some neoplastic diseases, some cases of myxedema, traumatic tap, and in CSF obtained from below the level of an obstruction of the spinal cord. Decreased total protein in CSF may be observed with dilution from water intoxication, CSF leak (CSF rhinorrhea or otorrhea), and hyperthyroidism.

Clinical Utility

Evaluation of meningitis, neoplastic involvement of meninges, and other neurological disorders.

Reference

1. Henry's Clinical Diagnosis and Management by Laboratory Methods, 22^nd Ed. 2011.

CPT Codes

82945 (Glucose), 83615 (LD), 83605 (Lactic Acid), 84157 (Protein, Total).

Contacts

Last Updated

10/30/2023