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Test Code LASF1 Lactic Acid, Spinal Fluid


Specimen Required


Specimen Type: Spinal fluid

Container/Tube: Sterile container

Specimen Volume: 1 mL

Collection Instructions: Centrifuge to remove any cellular material.


Useful For

Aid in differentiating between bacterial and viral meningitis

 

Aid in identifying increased anaerobic glycolysis or hypoxia associated with bacterial meningitis, cerebral infarction, cerebral arteriosclerosis, intracranial hemorrhage, hydrocephalus, traumatic brain injury, cerebral edema, epilepsy, and inborn errors of metabolism

Method Name

Colorimetric

Reporting Name

Lactic Acid, CSF

Specimen Type

CSF

Specimen Minimum Volume

0.5 mL

Specimen Stability Information

Specimen Type Temperature Time Special Container
CSF Frozen (preferred) 60 days
  Refrigerated  24 hours
  Ambient  3 hours

Reject Due To

Gross hemolysis OK
Gross lipemia OK

Clinical Information

Anaerobic glycolysis markedly increases lactate concentrations. Lactate concentrations in cerebrospinal fluid (CSF) are increased in the presence of cerebral glycolysis or hypoxia associated with bacterial meningitis, cerebral infarction, cerebral arteriosclerosis, intracranial hemorrhage, hydrocephalus, traumatic brain injury, cerebral edema, epilepsy, and inborn errors of metabolism. Lactate found in CSF is predominantly produced by central nervous system anaerobic glycolysis and is independent of blood lactate. Lactate measurement in CSF has been proposed as a test to differentiate bacterial from viral meningitis.

Reference Values

0-2 days: 1.1-6.7 mmol/L

3-10 days: 1.1-4.4 mmol/L

11 days-17 years: 1.1-2.8 mmol/L

>17 years: 1.1-2.4 mmol/L

Interpretation

In addition to reference intervals, published meta-analysis of 33 studies concluded concentrations greater than 3.9 mmol/L are suggestive of bacterial meningitis, with lower concentrations suggestive of viral meningitis.(1)

Cautions

Cerebrospinal fluid (CSF) lactate concentrations should be interpreted in conjunction with clinical findings and other laboratory results.

 

CSF lactate concentrations decrease after treatment with antibiotics; therefore, specimens should be collected prior to initiation of antibiotics in order to differentiate bacterial from aseptic meningitis.

Method Description

Lactate concentration is determined using an enzymatic colorimetric method. L-lactate is oxidized to pyruvate by the specific enzyme lactate oxidase. Peroxidase is used to generate a colored dye using the hydrogen peroxide generated in the first reaction. The intensity of the color formed is directly proportional to the L-lactate concentration. It is determined by measuring the increase in absorbance.(Package insert: Roche Diagnostics Cobas 6000; LACT2 reagent package insert; Indianapolis, IN 46256. 02/2016)

Day(s) Performed

Monday through Sunday

Report Available

Same day/1 to 2 days

Specimen Retention Time

1 week

Performing Laboratory

Mayo Clinic Laboratories in Rochester

Test Classification

This test has been cleared, approved, or is exempt by the US Food and Drug Administration and is used per manufacturer's instructions. Performance characteristics were verified by Mayo Clinic in a manner consistent with CLIA requirements.

CPT Code Information

83605

LOINC Code Information

Test ID Test Order Name Order LOINC Value
LASF1 Lactic Acid, CSF 2520-5

 

Result ID Test Result Name Result LOINC Value
LASF1 Lactic Acid, CSF 2520-5