Introduction: when patients with chronic back pain seek general surgery, it's typical to see them abusing opioids and other medicines. There have been reports of substance abuse and misuse among these patients as a result of the excruciating pain. Patients who have abused opioids and other medications over an extended period of time have begun to experience painful postoperative adverse effects. Planning for appropriate preoperative optimization and perioperative management is aided by toxicology screening tests (TST). Aim of the study to determine whether TST is feasible and whether it could deliver information that is more trustworthy than self-reporting.Method: we created a cross section research to track the accuracy of these patients' self-reports and TST tested all abused substances. Results: There was a statistical significant strong positive correlation between number of drugs detected in TST and induction dose of propofol (Spearman correlation r=0.78), suggesting that the dose of propofol should be raised when the number of drugs used was increased, pain score in the last week (r=0.84), as well as length of hospital stay (r=0.71) with p value <0.001. Conclusion: Larger prospective, randomized investigation to establish the clinical basis for routine preoperative TST and to put recommendations into practice in chronic back pain patient undergoing elective surgeries.