Lactic acidosis is a still relatively uncommon but very serious condition.
The prevailing view is that lactic acidosis represents a form of mitochondrial toxicity possibly due to the class of drugs known as the nucleoside reverse transcriptase inhibitors. Severe cases can be fatal. The lactic acid level measured in the blood can be raised by exercise prior to the blood draw so there are a number of issues relative to the accurate diagnosis of the condition. Mild cases without symptoms can be observed and often the level of lactic acid will go up and down. More severe cases with symptoms requires prompt attention.