An essential part of the laboratory in Therapeutic Drug Monitoring (TDM) is clinical drug analysis and a careful clinical-pharmacological evaluation of pharmacotherapy. Internal and external quality assurance in this laboratory is carried out in accordance with the “Guideline of the German Medical Association for the Quality Assurance of Quantitative Laboratory Medical Examinations 2023” and on participation in ring control examinations – round robin tests (since 1976). Since 26.05.2022, the QM system of the TDM laboratory meets the requirements of the IVDR2022 for the use of in-house in-vitro diagnostics (IH-IVD). In August 2021, in the course of tendering and procurement of a laboratory information system software, the TDM laboratory was completely connected to the laboratory information system (LIMS), and thus also to the Centre for Laboratory Diagnostics (CLD).
For the TDM, the measurement of a trough concentration of pharmaceuticals and partly also their active metabolites in the blood, plasma, serum or saliva is required in order to be able to monitor the treatment of drugs with a narrow therapeutic range. Currently, more than 50 substances (partially plus metabolites) are routinely analysed using HPLC-UV-Vis and HPLC-MS/MS analysis methods. The TDM method spectrum includes a larger number of different substances mainly in the field of psychotropic drugs, antiepileptic drugs, cardiaca, anti-infectives (antimycotics/-biotics), tyrosine kinase inhibitors (midostaurin, axitinib, cabozantinib, lenvatinib) and oral anticoagulants (DOACs). Pharmaceuticals are particularly important for pharmacotherapy in the field of intensive care (amiodarone and desmethyl-amiodone, levetiracetam and antibiotics): in these functional areas, a rapid analysis and the short-term clinical-pharmacological evaluation and thus the so-called turn-around-time (TAT) is of relevance for therapy optimization.
A sole transmission of results does not correspond to the understanding of a TDM. Rather, in the clinical context, a written clinical-pharmacological report in a briefly matter is created in a short form based on a software-assisted evaluation (e.g. MwPharm+, DoseMe) afterwards, taking into account all demographic data and times. This is the rule! In this report all time-concentration profiles are simulated and assessed individually taking into account the dosage, codification, body weight, as well as kidney and liver function parameters of the serum concentration course. The following information and questions are of relevance: evaluation of subtherapeutic, therapeutic or toxic concentrations, interactions with comedic medication, completeness of absorption, bioavailability, elimination half-life, regularity of intake (non-adence) and, if necessary, the dosage change in order to achieve target concentrations.