The aim of toxicological screening is to detect drugs of abuse and other drugs, or to demonstrate that they have not been taken. It is performed with a variety of tests capable to detect certain substance or a group of substances. Urine is a sample of choice for toxicological screening because of less invasive sampling and the prolonged detection time of substances in urine. The Department of Laboratory Diagnostics at the University Hospital Centre Zagreb used to perform screening with thin-layer chromatography and confirm results with GC-MS analysis. Since September 2014, the Department has been using GC-MS for toxicological screening 24 hours a day. Compared to the previous period, the experience acquired so far has shown that there are a significantly lower number of samples with unknown substances that cannot be confirmed with certainty.
Key words: gas chromatography, mass spectrometry, toxicological screening