Final answer:
Lactic acid tests measure the level of lactate produced by lactic acid fermentation, an anaerobic process aided by the enzyme LDH, and do not involve oxygen in the process.
Step-by-step explanation:
The lactic acid tests are performed to measure the concentration of lactate in the blood, which is a product of lactic acid fermentation. This anaerobic process occurs in muscle cells during intense exercise when oxygen is scarce, as well as in red blood cells that lack mitochondria. The key enzyme involved in this reaction is lactate dehydrogenase (LDH). The resulting lactic acid must be transported out of the muscles by the blood circulation and brought to the liver, where it can be converted back into pyruvic acid and used for further energy production. A lactic acid test typically does not use a process involving oxygen, as the reaction takes place under anaerobic conditions.