From the Research
Conventional laboratory tests for lactate typically detect only L-lactate, not D-lactate. Standard clinical lactate assays use the enzyme lactate dehydrogenase (LDH) or lactate oxidase, which are specific for L-lactate and have minimal reactivity with D-lactate, as demonstrated by a study published in 2023 1. This specificity is important because L-lactate is the predominant form produced in normal human metabolism through glycolysis, while D-lactate is not a significant metabolic product under normal conditions.
When clinicians order a "lactate level" in routine clinical practice, they are receiving information about L-lactate concentrations only. Specific testing for D-lactate requires specialized assays that are not routinely available in most clinical laboratories and must be specifically requested when D-lactic acidosis is suspected, such as in cases of short bowel syndrome or certain bacterial overgrowth conditions, as discussed in a review published in 2020 2.
This distinction is clinically relevant because elevated D-lactate can cause neurological symptoms but would be missed on conventional lactate testing. The development of new assays, such as the one described in the 2023 study 1, which can detect L-lactate with high selectivity and sensitivity, further highlights the importance of distinguishing between L-lactate and D-lactate in clinical practice.
Key points to consider:
- Conventional laboratory tests detect only L-lactate
- Specialized assays are required to detect D-lactate
- Elevated D-lactate can cause neurological symptoms and may be missed on conventional lactate testing
- New assays are being developed to improve the detection of L-lactate and distinguish it from D-lactate, as seen in the 2023 study 1 and the 2022 study 3.