Although the COVID-19 pandemic still had an impact on the medical biology department in 2021 – 3 fixed-term contracts and 4 temporary staff members were recruited during the year to manage the registration of tests from the various screening centres set up by the Laboratoire national de santé (LNS) – thus allowing the other units to continue their development. The toxicology unit recorded an increase in activity of 27% in 2021 compared to 2020. Amongst the new features, the department now offers antibiotic testing to optimise the treatment of patients in intensive care units, as well as a new panel for the identification of 80 drugs and medicines in urine samples. The department has also been accredited by the OLAS, amongst others, for determining the quantity of cannabis in urine.
Fine tuning of antibiotic dosing
Sepsis is a major cause of morbidity and mortality in intensive care units (ICUs), resulting in a 10-fold increase in antibiotic consumption in these units compared to other hospital departments. Adapting the dosing of these molecules allows both to increase the chances of therapeutic success by taking into account the specificities of each patient, as well as to rationalise the use of these molecules in order to combat the problems caused by antibiotic resistance.
The clinical toxicology service of the LNS’s medical biology department has initiated the development of antibiotic dosing for patients in intensive care at the request of resuscitators. “This shows that we have become a real partner in medical toxicology for prescribers,” says Dr pharm, Dr sc. Patricia Borde, Head of Department.
The application of standard dosing regimens for patients in intensive care may result in concentrations that are too low or, on the contrary, toxic for many of them. This is where therapeutic drug monitoring (TDM) can be useful: the concentration of antibiotics is measured for the patient in question and the dosage can be adjusted accordingly. “This makes it possible to distinguish between the effective dose and the toxic dose, to avoid over- or under-dosing, whether the patient is seriously ill, obese, with reduced renal function or a very young child, for example,” explains Patricia Borde.
This ensures that medicines are used appropriately, improving patient outcomes, and reducing costs for the hospital.
Traditionally, immunoassays were used in TDM due to the rapidity of the tests, because of a high degree of automation. However, the reliability of the test results can sometimes be questioned. The antibodies used in the assay may be cross-reactive, resulting in falsely high values. The separative techniques (HPLC, LC-MS) used at the LNS are reference methods and offer the best performance in terms of analytical sensitivity and specificity.
Toxicological screening in urine: implementation of an expanded panel of 80 drugs and medications
Drug abuse is one of the most important public health problems in the world, both in terms of illicit drug use and prescription drug misuse. Cannabis is by far the most widely used drug in Europe. Stimulants such as cocaine, MDMA and amphetamines are far behind. Within the opioid category, heroin remains the most widely used drug.
The LNS’ medical biology department is also involved in the detection of drug addiction. When treating patients undergoing drug detoxification, the department checks for abstinence from illicit drugs during substitution treatments. In occupational medicine, drug testing is used to verify abstinence and to determine whether or not a patient is suitable to drive or not. Finally, accurate testing can also help save lives when an intoxicated person arrives at A&E in an unconscious state.
The new panel includes 80 drugs and metabolites. It allows for these molecules to be identified and quantified in a relatively short analysis time. The technique used (LC-MSMS) has a high specificity and sensitivity. “The benefits are not necessarily immediately apparent to doctors, but for us in the laboratory, it makes our lives much easier and is a great technical advance,” states Patricia Borde.
Accredited for the quantification of cannabis in urine
Another of the toxicology service successes: the department is now certified for establishing the quantity of cannabis in urine by mass spectrometry. This assay is used to monitor the evolution of consumption in patients who are addicted or undergoing detoxification. As cannabis remains in the body for a very long time, this analysis makes it possible to differentiate between the normal release of THC after its elimination, and a resumption of consumption.
Overall, all these innovations have certainly contributed to the increase in activity of the toxicology service in 2021,” says Patricia Borde. “We hope to be able to maintain this trend for the whole department and the LNS in general in the future in order to continue to best serve Luxembourg’s population.”