This test measures the amount of lactate in the blood or, more rarely, in the cerebrospinal fluid. Lactate is the ionic (electrically charged) form of lactic acid. It is produced by muscle cells, red blood cells, brain, and other tissues during anaerobic (oxygen deficient) energy production and is usually present at low concentrations in the blood. Aerobic energy production is the body’s preferred process, but it requires an…This test measures the amount of lactate in the blood or, more rarely, in the cerebrospinal fluid. Lactate is the ionic (electrically charged) form of lactic acid. It is produced by muscle cells, red blood cells, brain, and other tissues during anaerobic (oxygen deficient) energy production and is usually present at low concentrations in the blood. Aerobic energy production is the body’s preferred process, but it requires an adequate supply of oxygen. Aerobic energy production occurs in the mitochondria, tiny power stations inside each cell of the body that use glucose and oxygen to produce ATP (adenosine triphosphate) which is the body’s main source of energy. When cellular oxygen levels are low, or the mitochondria are not working properly, the body must turn to less efficient anaerobic energy production to metabolise glucose and produce ATP. In this process, the primary by-product is lactic acid, which can build up faster than the liver can break it down. When lactic acid levels increase a lot in the blood, the affected person is said to have first hyperlactataemia and then lactic acidosis (LA). The body can often compensate for the effects of hyperlactataemia, but lactic acidosis can be severe enough to disrupt a person’s acid/base (pH) balance and cause symptoms such as muscular weakness, rapid breathing, feeling sick, vomiting, sweating, and even coma.Lactic acidosis is separated into two types: A and B. Type A is more common and may be due to inadequate oxygen uptake in the lungs and/or to decreased blood flow (hypoperfusion) resulting in decreased transport of oxygen to the tissues. The most common reason for this is shock from a variety of causes including trauma and blood loss, but LA may also be due to conditions such as heart attack, congestive heart failure, and pulmonary oedema (fluid in the lungs). Type B is caused by conditions that increase the amount of lactate/lactic acid in the blood but are not related to a decreased availability of oxygen. This includes liver and kidney disease, diabetes, leukaemia, AIDS, glycogen storage diseases (such as glucose-6-phosphatase deficiency), drugs and toxins, severe infections (both systemic sepsis and meningitis), and a variety of inherited metabolic and mitochondrial diseases (forms of muscular dystrophy that affect normal ATP production). Strenuous exercise can also result in increased blood lactate concentrations. How is the sample collected for testing? A blood sample is obtained by inserting a needle into a vein in the arm. Sometimes, an arterial sample is collected by inserting a needle into an artery. Occasionally, a sample of cerebrospinal fluid is collected from the spinal column during a procedure called a lumbar puncture. Is any test preparation needed to ensure the quality of the sample? Fasting may or may not be required. Ask your doctor. You may also be told not to exercise for a period of time before this test. See MoreSee Less
