The answer is not necessarily. Although blood testing for marijuana is available, it is unlikely your blood would be tested if you did not end up in the hospital due to an accident.
However, there are other ways that the state can seek to prove you were under the influence of cannabis. Police have specialized field sobriety tests for marijuana that are separate from the field tests for alcohol. For example, the Romberg test examines if you can maintain your balance with your eyes closed. Another example is the horizontal gaze nystagmus test which tests whether your eyes bounce up and down when following an object from side to side. This later test is often used for alcohol DUI.
If you are charged with a cannabis-related DUI or similar offense, contact an experienced attorney immediately. An attorney can review your case for your best possible defense. Was the officer certified as a drug expert? Are there other reasons that you might have performed poorly on the test? Was any cannabis recovered from you or the car? Even if the evidence against you is overwhelming and nearly impossible to challenge, an attorney who is respected in the courthouse may be able to negotiate a more favorable plea agreement than you could on your own.
If you have questions about this or another related Illinois criminal or traffic matter, please contact Matt Keenan at 847-568-0160 or email firstname.lastname@example.org.
(Besides Skokie, Matt Keenan also serves the communities of Arlington Heights, Chicago, Deerfield, Des Plaines, Evanston, Glenview, Morton Grove, Mount Prospect, Niles, Northbrook, Park Ridge, Rolling Meadows, Wilmette and Winnetka.)