Plasma
CSF
Adult patient:
Fluoride tube
Minimum blood volume: 2 mL
Adult patient:
Fluoride tube
Minimum blood volume: 2 mL
Paediatric patient:
Paediatric fluoride tube
Number of vials: 1
Minimum blood volume: 1.3 mL
Paediatric patient:
Paediatric fluoride tube
Number of vials: 1
Minimum blood volume: 1.3 mL
Authorisation code required
No
24 Hr available service
Yes
Yes
Precaution
Blood samples should be drawn from a stasis-free vein. However, minimal haemostasis (less than 30 sec) will not affect lactate levels. Avoid the use of a tourniquet, if possible. Blood or CSF samples should be sent in ice without delay.
Method
Spectrophotometry
Reference interval
Plasma: < 2.2 mmol/L
(Source: modified from manufacturer's reagent insert)
CSF: 1.1 - 2.8 mmol/L
(Source: Privitera MD, Kohler C. Nervous System. In: Kaplan LA, ed. Clinical Chemistry: Theory, Analysis, Correlation. 3rd Edition. Mosby, 1996: P832)
Clinical indication
Plasma:
Investigation of metabolic acidosis with an increased anion gap
Cerebrospinal fluid (CSF):
Aid in differentiation between bacterial and aseptic meningitis.
Result interpretation
Plasma:
Lactate levels may be increased in association with diabetes mellitus, shock, hypoxia, congestive heart failure, phenformin therapy and in numerous other pathological states and metabolic disorders.
Lactic acidosis in children may have a genetic origin.
Cerebrospinal fluid (CSF):
In bacterial and cryptococcal infection, an increased CSF lactate is found earlier than a reduced glucose.
In viral meningitis, lactate levels remain normal, even when neutrophils are present in the CSF.
Raised levels may also occur with severe cerebral hypoxia or genetic lactic acidosis.
Measurement of uncertainty
Frequency of measurement
Daily