Detection of AC in blood or urine samples, or in body tissues collected post-mortem, is key for the diagnosis of clinical cases and a requirement for surveillance of secondary toxicosis, including potential cases in wild animals (5). At the time when the reports of suspected secondary AC-poisoning in cats were emerging, reports on poisoning of humans and non-laboratory animals confirmed by the detection of AC were available. Reports on clinical cases of AC-poisoning in cats were however rare. Furthermore, reports on clinical cases in domestic animals rarely report quantifications of AC in blood or body tissues. In a Swedish study performed by Windahl et al., the validation of a quantitative ultra high performance liquid chromatography--tandem mass spectrometry (UHPLC--MS-MS) method, fit for use in cases of suspected AC poisoning in cats, was described (5). The method was used in a study on AC poisoning in cats in Sweden, quantifying AC concentration in blood samples from 25 suspected cases (2). In the study, the intoxication severity was scored, and this correlated with the detected AC concentration. The validated method was also used later in the study by Windahl et al. (1) on AC-poisoning in cats in Nordic countries where the lowest measured serum concentration of AC was 127 ng/mL and the highest 70 100 ng/mL (fig. 3). The mean and median concentrations were 5 597 and 3 740 ng/mL, respectively.