The ionic composition of interstitial and intravascular fluids is the same. Proteins, however, are kept with the vascular compartment, at least to a degree, by the vascular wall, which is a semi-permeable membrane. The concentration of proteins is much higher in the plasma sector than in the interstitial sector.
Detection of marijuana using swab drug test can vary from person to person taking into account the different conditions like general health, different fluid intake, metabolism, etc.
Mouth swab drug test facts indicate that the test can be used to test for usage of drugs such as cocaine, marijuana, opiates, methadone, phencyclidine, benzodiazepines, amphetamines, and methamphetamines.