## 4 Discussion
analyzed BHB values in VH and CSF collected from the cerebral ventricular system and lumbar region in 20 autopsies [31; 32]. Even though no significant differences were found between BHB values in fluids collected from the three sites, [PERSON] et al. made no suggestion concerning the optimal site for BHB determination, as all values were within physiological limits [31; 32]. When analyzing individual values obtained in our research, we observed that the lowest BHB values were obtained from lumbar CSF. Unlike the values quantified in the cisterna magna CSF, those obtained from the lumbar CSF correlated less with the values obtained from the other body fluids. Thus, we consider that determination of BHB in CSF collected by lumbar puncture should be avoided in favor of that collected from cisterna magna. We were unable to identify any other study that compared BHB values in CSF collected from the two sites. Detection of abnormal BHB values above the threshold led to the identification of nine cases of ketoacidosis using the MAK041 test kit and 11 cases using the handheld multi-purpose \(\beta\)-analyzer. All nine cases of ketoacidosis identified using the MAK041 kit were also confirmed with the portable \(\beta\)-analyzer. These results demonstrate once again the reliability of the methods used in our study, especially the determinations performed using the MAK041 kit. For the 2 cases of ketoacidosis identified only by using the portable \(\beta\)-analyzer, the values obtained from the MAK041 kit were at the upper limit of the normal range (0.42-0.47). In these 2 cases, we cannot exclude a possible overestimation of ketoacidosis when only using the rapid test. A recent study published by [PERSON] et al. highlights the excellent specificity and sensitivity of BHB values obtained with a portable analyzer operating according to the same principle as the one used in our research [27]. Moreover, [PERSON] et al. recommend the routine use of a portable analyzer in forensic practice, especially for cases of suspected metabolic imbalance [27]. Our results support this suggestion, as the nine ketoacidosis cases did not occur secondary to diabetes or alcohol abuse and require the investigation of other causes of death. A significant advantage of BHB determination is the post-mortem stability of this biochemical marker for 24-72 h. Our results are consistent with those published in the literature, which emphasize the post-mortem stability of BHB compared to Ac or other biochemical markers as mean values obtained at various PMI did not significantly differ [1; 6; 9; 19]. In terms of the applicability, the usage of the MAK041 test kit is more laborious, as more samples need to be collected to perform the actual determinations. Also, it has been developed for research purposes and our study is the first to use it for forensic analysis. At the opposite, the portable multifunctional monitoring system-XPER-Technology II, is easy to use and fast, the results being obtained while performing the autopsy or immediately after. The major limitation of this research is the lack of baseline control values, the relative small number of cases included, as well as the fact that one of the applied methods for determining BHB is experimental and used for the first time in the forensic field. Even though in our study we did not determine BHB from VH using the portable multifunctional analyzer, it is worth pointing out the controversies in the literature: [PERSON] et al. identified excellent sensitivity and low specificity, while [PERSON] et al. identified the same sensitivity but much better specificity (0.72 vs. 0.50) [27; 33]. Of course, further studies employing similar methods are needed to provide even greater credibility. Given the limitation underlined above, we plan to continue this study direction and validate the multiple analyzer for use in forensic determination of BHB on a large sample of cases with and without antimortem causes of ketoacidosis.