L-lactate is a biomarker used to assess tissue hypoxia and ischaemia, which can be caused by gastrointestinal dysfunction. Lactate exists is two stereoisometric forms; the two isomers are known as L-lactate and D-lactate. L-lactate is the predominant form in the human body. L-lactate is a metabolite in the two main energy producing processes in the human body, glycolysis and oxidative phosphorylation. L-lactate is disposed via the liver and kidneys following coversion to pyruvate by L-lactate dehydrogenase. Hyperlactatemia occurs if the rate of lactate production exceeds the rate of removal. The most common cause of hyperlactatemia is increased production from anaerobic glycolysis due to reduced oxygen delivery to the cells.
Feasibility/Equipment: Routinely measure on blood gas samples in critical care units.
Scoring information: Normal lactate levels are less than two mmol/L, with hyperlactatemia defined as lactate levels between 2 mmol/L and 4 mmol/L. Severe levels of lactate are 4 mmol/L or higher.
Cost: Low/routinely measured.
Evidence: A study investigating the predictive and prognostic value of L-lactate in diagnosis of acute mesenteric ischemia (AMI) found L-lactate had no predictive value in diagnosis of AMI. Another study found the value of serial lactate to predict the length of necrotic bowel is very limited, however lactate values were independent risk factors for mortality
Accuracy / measurement properties: Non-specific to GI dysfunction/GI tissue hypoxia.
References:
Destek S, Yabacı A, Abik YN, Gül VO, Değer KC. Predictive and prognostic value of L-lactate, D-dimer, leukocyte, C-reactive protein and neutrophil/lymphocyte ratio in patients with acute mesenteric ischemia. Ulus Travma Acil Cerrahi Derg. 2020 Jan;26(1):86-94.
Studer P, Vaucher A, Candinas D, Schnüriger B. The value of serial serum lactate measurements in predicting the extent of ischemic bowel and outcome of patients suffering acute mesenteric ischemia. J Gastrointest Surg. 2015 Apr;19(4):751-5.