Perioperative anaphylaxis is a potentially life-threatening drug allergic reaction that can occur during anesthetic procedures. The purpose of this research is to determine the maximal nonirritating skin testing concentrations of midazolam, ketamine and ondansetron. These drugs are FDA approved and commonly used before, during and after surgical procedures.

Inclusion Criteria:

• Not have a history of an adverse reactions to midazolam, ketamine or ondansetron
• Ability to understand study procedures and to comply with them for the entire length of the study.
• Contraception is not necessary, and we will include women of reproductive capability.

Exclusion Criteria:

• Unstable patients.
• History of any adverse reaction (allergy or sensitivity) to midazolam, ketamine or ondansetron.
• Pregnant and Pediatric patients
• Inability or unwillingness of individual or legal guardian/representative to give written informed consent.