Lactate or pyruvate disorders: lactate

CLAPY

Chemical Pathology - Routine Laboratory

Lactate formation occurs when there is insufficient oxygen present to allow complete oxidation of glucose to CO2 and H2O. Elevated circulating lactate can occur when there is increased metabolism as is seen in intense muscular activity, or if there is poor tissue perfusion as occurs in oxygen starvation, septicaemia, shock diabetes and in liver disease. It can also be observed in mitochondrial defects. Elevated blood lactate results in an acidosis, characterised by low plasma CO2 concentration and high anion gap. In body tissue, lactate is converted to pyruvate by lactate dehydrogenase, the normal equilibrium being about 10:1 in favour of lactate. This ratio rises in anoxia as tissue NADH raises during the equilibrium of the reaction below to the left

1. 2ml fluoride oxalate plasma or

2. perchloric acid precipitation (see appendix for protocol) or

3. 0.2ml clear CSF

1. Separate plasma assay ASAP

2. Freeze immediately. Send frozen

3. Freeze immediately. Send frozen

1. 6 hours

2. 1 to 2 weeks

3. 1 to 2 weeks

Not applicable

Yes