Adherence may be understood as the extent to which a person’s behavior corresponds to recommendations from health care providers. In clinical toxicology, the monitoring of 2 types of adherence is important. The first is pharmacological abstinence from drugs of abuse (DOA), ethanol, or misused prescription drugs in the context of substance use disorders. The second is pharmacological adherence, which means that the patient takes the medication as prescribed. Bioanalytical measurements of drugs, metabolites, or biological markers in different specimens allow direct monitoring of patient adherence. The progress in bioanalytics provides us the opportunity to use alternative biosamples to venous blood and urine for toxicological investigations. One example are dried capillary blood samples. The sampling is minimally invasive as venipuncture is not required. Nonvolumetric sample collection can be performed by free falling or touching a filter paper resulting in dried blood spots (DBS). Urine can also be dried on filter paper resulting in dried urine spots. Meanwhile, numerous specific devices also allow volumetric sample collection. However, the low-volume sample collection strategy claims sensitive analysis techniques. The talk will give an overview of applications of dried matrix samples in clinical toxicology with focus on adherence monitoring, discuss current studies, and highlight advantages and disadvantages of the sampling strategies.
