Undetectable triglycerides related to the combined intake of ascorbic acid and tacrolimus.

Management of triglyceride (TG) levels is essential in intensive care units (ICU), especially to manage the risk of pancreatitis induced by propofol. However, some therapeutics in ICU such as intravenous ascorbic acid protocol, especially used in the context of Covid-19 could lead to false decrease of triglycerides by analytical disruption of Trinder reaction. We report here the case of a sample with unmeasurable triglyceride levels partly due to high plasma ascorbic acid levels. However, repeated measure on the same sample four days later revealed that interference mechanism on TG was still present whereas the level of ascorbic acid was very reduced by oxidation degradation. Hence, additional interference mechanism was suspected. After clinical investigation, we found that the patient had also received high doses of tacrolimus due to a transplant. As previous studies reported that tacrolimus treatment lead to a decrease of the measured plasma activity of lipoprotein lipase (LPL), we hypothesized that tacrolimus or related metabolites could also interfere by direct inhibition of LPL involved in TG analytical method used.

Antioxidants other than vitamin C may be detected by glucose meters: Immediate relevance for patients with disorders targeted by antioxidant therapies.

Owing to their ease of use, glucose meters are frequently used in research and medicine. However, little is known of whether other non-glucose molecules, besides vitamin C, interfere with glucometry. Therefore, we sought to determine whether other antioxidants might behave like vitamin C in causing falsely elevated blood glucose levels, potentially exposing patients to glycemic mismanagement by being administered harmful doses of glucose-lowering drugs. To determine whether various antioxidants can be detected by seven commercial glucose meters, human blood samples were spiked with various antioxidants ex vivo and their effect on the glucose results were assessed by Parkes error grid analysis. Several of the glucose meters demonstrated a positive bias in the glucose measurement of blood samples spiked with vitamin C, N-acetylcysteine, and glutathione. With the most interference-sensitive glucose meter, non-blood solutions of 1 mmol/L N-acetylcysteine, glutathione, cysteine, vitamin C, dihydrolipoate, and dithiothreitol mimicked the results seen on that glucose meter for 0.7, 1.0, 1.2, 2.6, 3.7 and 5.5 mmol/L glucose solutions, respectively. Glucose meter users should be alerted that some of these devices might produce spurious glucose results not only in patients on vitamin C therapy but also in those being administered other antioxidants. As discussed herein, the clinical relevance of the data is immediate in view of the current use of antioxidant therapies for disorders such as the metabolic syndrome, diabetes, cardiovascular diseases, and coronavirus disease 2019.