Lactate

A lactate test can identify oxygen deficiency or other conditions that cause excess production of lactate, the ionic (electrically-charged) form of lactic acid. In HIV infection, lactic acidosis is rare, but hyperlactataemia is common. It can be caused by mitochondrial toxicity or an inherited metabolic disorder.

Most nucleoside analogue drugs used in HIV treatment can cause elevated lactate levels. Once the condition is identified, it can usually be treated by switching to another drug in the NRtI class.

Symptoms of excess lactate include shortness of breath, fatigue, nausea, and excess sweating.

Sometimes fasting is required, but not always. The test is usually done using a blood sample drawn from a vein in the arm. The test can also be performed on a sample drawn from an artery or from cerebrospinal fluid (CSF). A CSF sample for lactate might be taken if someone had symptoms of meningitis such as severe headache, fever, delirium, and loss of consciousness or as an add-on to another test requiring that method. Point of care devices are available at relatively low cost and have improved diagnosis and treatment of excess lactate in Haiti and South Africa.^{1 2}

Test results are used to detect and quantify oxygen shortage (hypoxia) from lactic acidosis. If there is an excess of lactate, a change of ARV regimen will probably be made. Lactate levels are also used to monitor heart conditions and shock.