Abuses of new psychoactive substances have recently become serious social problems. When synthetic cannabinoids are consumed, most of the drugs are not detected in unchanged form from the urine. In that cases, it is difficult to determine what drug was consumed in drug testing. If blood and saliva of suspects are obtained immediately after drug consumption, unchanged drugs could be detected from the specimens. Therefore, on-site sampling of these specimens are effective to determine the consumed drugs. We examined how police officers easily obtain blood and saliva of suspects on site and what drug concentrations are needed to detect drugs in blood and saliva obtained by the sampling methods. First, blood and saliva sampling methods were examined using various collecting tools. For blood sampling method, it was effective to bleed from a fingertip with a lancet and then to absorb the blood to paper pulp. Blood of approximately 5 μL was obtained by this safe and simple method. For saliva sampling method, dropping saliva directly into a 25 mL centrifuge tube (direct sampling method) was convenient for drug analysts. However, because some subjects felt it unpleasant that the sampling situation was watched by the observer, the alternative sampling method, absorbing saliva in a mouth with a cotton swab was also used. Saliva of at least 50 μL was obtained by the two methods. Next, five drugs (JWH 018, 5F-APINACA, 4-MeO α-PVP, 4-Cl AMP and MeBP) in blood and saliva were analyzed using a liquid chromatograph-ion trap mass spectrometer to estimate the concentrations required for drug detection. The limits of detection of five drugs were in the range of 0.1-10 ng/mL for blood (5 μL) and 0.01-1 ng/mL for saliva (50 μL) obtained by the direct sampling method. On the other hand, absorbing saliva by a swab made drug detection difficult because synthetic cannabinoids, JWH 018 and 5F-APINACA, were strongly adsorbed in the swab. It is considered that saliva obtained by the direct sampling method is effective for drug testing because the sampling is rapid and simple, a large volume of saliva is obtained, and the drug concentrations in abusers' saliva are generally high as compared with those in blood.