OVERVIEW
What is lactate level (CSF) lab test?
Lactate is substance made by muscle tissues and is produced when body turns food into energy (cell metabolism). Depending upon pH, it can be present in lactic acid form as well, but mostly because of neutral body pH, the lactate form is present in blood. Lactate levels are normally very low in CSF (cerebrospinal fluid). However, if there are inadequate cellular oxygen levels, or when primary ways of energy production are disrupted, then it leads to excess lactate production by muscle cells/RBCs/brain or other tissues. This laboratory test is used to measure concentration of lactate found in CSF (cerebrospinal fluid).
Why is lactate level (CSF) lab test done?
Initially this test is done to distinguish among viral & bacterial meningitis (inflammation of meninges). It is performed:
- For identifying increased anaerobic glycolysis or hypoxia (body deprived of oxygen) associated with bacterial meningitis
- In stroke (cerebral infarction)
- In cerebral arteriosclerosis (thickening and hardening of walls of the arteries in brain)
- In intracranial hemorrhage (brain bleed)
- In traumatic brain injury
- In cerebral edema (fluid builds up around the brain)
- Epilepsy (central nervous system disorder).
- What can happen if there is high lactate?
Having higher than normal lactic acid levels leads to condition called lactic acidosis. If severe enough, then it will upset body’s pH balance.
- What is considered normal lactate level?
Levels less than 1.0 mmol/L in both venous & arterial blood is normal lactate.
- What are critical lactate levels?
Normal lactate concentration in blood of unstressed patient is 0.5 to 1 mmol/L, while, in critical illness patient normal lactate levels are less than 2 mmol/L.
- What do blood lactate levels denote?
Having high lactate levels in blood indicates that a disease is causing lactate to accumulate. Also, greater increase in lactate means greater severity in disease condition.
- What does CSF protein high indicate?
Having abnormal protein level in CSF indicates CNS problem i.e. it could be sign of tumor, bleeding, nerve inflammation or injury.
INTERPRETATION OF THE RESULTS:
CSF lactate concentrations should be interpreted in combination with other laboratory results and clinical findings. Its normal ranges as per age are:
- Age 0-2 days: 1.1 – 6.7 mmol/L
- Age 3-10 days: 1.1 – 4.4 mmol/L
- Age 11 days to 17 years: 1.1 – 2.8 mmol/L
- Age > 17 years: 1.1 – 2.4 mmol/L
The CSF lactate with blood lactate level test is ordered when you feel symptoms of meningitis like severe headache, fever, delirium & loss of consciousness.