Lactate (lactate) is the end product of anaerobic glycolysis (breakdown of glucose occurring without consumption of oxygen). Lactates are salts and esters of lactic acid.Lactate formation occurs primarily in skeletal muscle, but also in the brain, erythrocytes (red blood cells), adrenal medulla, intestine, and skin, and is used for energy production. 60 to 70 % of the lactate produced is transported to the liver and is used in gluconeogenesis (formation of new glucose/sugar, e.g. in the case of a low-carbohydrate or carbohydrate-free diet). The kidneys are also capable of gluconeogenesis to a small extent. The heart meets more than half of its energy needs from the reoxidation of lactate (aerobic metabolic process) during high exercise. Normally, the body prefers aerobic (taking place with the consumption of oxygen) energy production, which takes place in the mitochondria (“power plants of the cells”) and ultimately produces the body’s main energy source, ATP (adenosine triphosphate). However, in the initial phase of short and intense exercise, the circulatory system is unable to supply the muscle cells with sufficient oxygen. In order to be able to quickly replenish the ATP stores, glucose is therefore broken down anaerobically to lactate, thereby gaining energy. This is very crucial for strength endurance and speed endurance sports, e.g. for a sprint. The required energy is quickly available, but the energy yield is low. During aerobic carbohydrate breakdown, a greater amount of energy is released, but at a slower rate. If the amount of lactate in the blood increases significantly, this is referred to as hyperlactemia, which can lead to lactic acidosis (lactate-induced hyperacidity/low pH in tissue and blood) in the further course.The increase in lactate concentration after heavy physical work or intensive sport, but also after epileptic seizures, is physiological and reversible, i.e. the increased lactate values quickly return to normal. However, a permanently elevated lactate concentration is pathological (pathological). Causes include hypoxia (insufficient oxygen supply to the organism or individual parts of the body), e.g., due to heart failure (cardiac insufficiency), shock, CO (carbon monoxide) poisoning, or reduced perfusion (reduced blood supply) to tissues, e.g., due to occlusion of the mesenteric artery (intestinal artery), trauma, and burns.
The procedure
Material required – depending on the indication.
- 1 ml sodium fluoride plasma or
- 0.5 ml cerebrospinal fluid (brain water) or
- 0.5 ml of punctate
Preparation of the patient
- Venous blood sampling should be done from the unstagnated vein, because the lactate concentration is higher in the stagnated vein than in the unstagnated vein.
- The patient should not pump by hand before blood collection, as this leads to increased lactate levels.
Collection instructions
Even in vitro (outside a living organism), erythrocytes degrade glucose to lactate. Consequently, the lactate values are distorted by this process. To inhibit glycolysis in the sample material immediately and permanently, mannose and sodium fluoride (NaF) are added to the sample material (glycolysis inhibitors). Addition of NaF alone also stops glycolysis, but only after two hours (full efficacy after 4 hours). Such samples must be taken immediately to the laboratory and centrifuged. Interfering FactorsIf the patient is taking any of the agents listed below therapeutically, the blood sample should be taken before the drug is administered because these agents cause falsely low lactate values:
- Acetaminophen (“paracetamol“/nonopiod analgesic (antipyretic and analgesic)).
- Metamizole (non-opiod analgesic).
- N-acetylcysteine (expectorant; used as an expectorant in respiratory diseases).
Normal values
| Material | mg/dl | mmol/l |
| Plasma [venous] | 5-20 | 0,5-2,2 |
| CSF | 11-19 | 1,2-2,1 |
| Punctate | 9-16 | 1-1,8 |
Indications
- Performance diagnostics in sports (see “Lactate test” below).
- Diagnostics of hidden tissue hypoxia
- Diagnosis of acute intestinal vascular occlusion (e.g., of the mesenteric arteries (intestinal arteries)).
- Bacterial meningitis (meningitis caused by bacteria).
- Prognosis and progression assessment of metabolic acidosis (metabolic acidosis).
- Prognosis and course assessment in circulatory shock and poisoning.
- Recognition of fetal distress at birth.
- Diagnostics in children with suspected inborn errors of metabolism.
Special indications for lactate in the cerebrospinal fluid.
- To differentiate the cause of diseases of the central nervous system.
- Inflammatory (inflammatory)
- Vascular (affecting the vessels)
- Metabolic (affecting the metabolism)
- Neoplasmic
Specific indications for lactate in the punctate.
- For the differentiation of inflammatory diseases
Interpretation of elevated values
- Acute alcohol intoxication [plasma].
- Acute inflammation, especially bacterial [punctate].
- Acute infections, e.g., HIV [plasma].
- Apoplexy (stroke) [cerebrospinal fluid]
- Chronic inflammation [punctate]
- CO poisoning [plasma]
- Seizure disorder (“grand mal seizure”) [CSF].
- Hypoglycemic (hypoglycemia-related) coma [CSF].
- Hyperlactemia with acidosis (lactacidosis) [plasma].
- Treatment with biguanides (in diabetes mellitus disease, eg, metformin).
- Heart failure (cardiac insufficiency).
- Cardiovascular failure
- Congenital (inborn) metabolic disorders.
- Fructose intolerance (fructose intolerance).
- Fructose-1,6-diphosphatase deficiency
- Pyruvate decarboxylase deficiency
- Shock
- Sepsis (blood poisoning)
- Burns
- Hyperlactemia without acidosis [plasma].
- High insulin levels
- Carbohydrate infusions
- Compensatory in hyperventilation (increased breathing beyond what is needed).
- Heavy physical activity and sports
- Postoperative
- Malignant processes [punctate; pleural punctate]
- Meningitis (meningitis) [CSF.]
- Partially treated meningitis [CSF].
- Bacterial meningitis [CSF].
- Systemic inflammatory response syndrome (SIRS) [plasma].
- Trauma [cerebrospinal fluid]
- Riboflavin (vitamin B2) deficiency [plasma].
| Material | mg/dl | mmol/l |
| Plasma [venous] | ||
| Hyperlactemia with acidosis (lactacidosis). | 45[and pH <7.35] | 5 |
| CSF | ||
| Meningitis (inflammation of the meninges)/encephalitis (inflammation of the brain) | ||
|
< 21 | < 2,4 |
|
> 30 | > 3,5 |
| Apoplexy (stroke) | 18-72 | 2-8 |
| Hypoglycemic coma | 18-36 | 2-4 |
| Seizure disorder | 18-54 | 2-6 |
| Punctate | ||
| Ascites (abdominal dropsy) | ||
|
14 ± 3 | 1,55 ± 0,3 |
|
22 ± 8 | 2,5 ± 0,9 |
| Pleural effusion | ||
|
5-45 | 0,65-5,2 |
|
45-200 | 5-22 |
| Synovial fluid | ||
|
< 37 | < 4,18 |
|
< 60 | < 6,82 |
|
9-17 | 1,0-1,8 |
Conversion factor
- Mmol/l x 9.008 = mg/dl
Interpretation of lowered values
- McArdle disease (synonyms: McArdle’s disease, McArdle myopathy, McArdle syndrome) – glycogen storage disease (glycogenosis) type V [plasma].
- Decreased lactate formation [plasma].
