A large number of new psychoactive substances are available at the illicit drug market and the synthetic cannabinoids (SCs) are among the substances that have led to serious side effects and death. Knowledge about common concentrations of these drugs are however sparse. Concentrations of APINACA and 5F-APINACA in biological matrixes have previously not been reported, and concentrations of UR-144 and its degradant product in blood samples from driving under the influence of drug (DUID) cases have not been published. The aims of this study were to report concentrations of APINACA, 5F-APINACA, UR-144 and UR-144 degradant from DUID cases analyzed at the Norwegian Institute of Public Health (NIPH), and also previously unpublished concentrations of AM-2201 in cases from our Institute. We have further summarized all the former published studies where concentrations of SCs have been reported, to compare with the results from these newer SCs. In whole blood from one driver we have found 5F-APINACA and from three drivers both APINACA and 5F-APINACA in concentrations from 0.24 to 24.5 and 0.9 to 6.5 µg/L, respectively, and UR-144 in two cases in concentrations of 0.22 and 0.47 µg/L. UR-144 degradant in a concentration of 0.15 µg/L was found in one of the cases. A summary of the literature reveals major deficiencies regarding concentrations of most of the SCs. The SCs most frequently detected in DUID cases were (n=8) AM-2201, JWH-122, JWH-018 and JWH-210. In intoxication cases AM-2201 (n=517) was the most often detected SC, followed by JWH-122, JWH-210, UR-144, JWH-018, and MAM-2201 (n>100). Four studies regarding concentrations in autopsy cases have been published, and concentrations of four different SCs have been reported (JWH-018, JWH-073, JWH-210, AM-2201 and the metabolites of AM-2201; 4-OH-pentyl, JWH-018 5-OH-pentyl and JWH-018 pentanoic acid). Pharmacokinetic data are only available for JWH-018 (n=3), JWH-073 (n=1) and the metabolites of AM-2201; 4-OH-pentyl, 6-OH-indole, JWH-018 5-OH-pentyl and JWH-018 pentanoic acid (n=1).