Amarillo Diagnostic Clinic 6700 W 9th AvenueBuilding BAmarillo, TX 79106 806.358.0200 Hours of Operation Mon – Fri 7:30 – 5:00 Amarillo Diagnostic Clinic medical marijuana clinic in Amarillo that certifies patients for their Texas MedCard. Please contact Amarillo Diagnostic Clinic’s office to schedule an appointment for initial visit, transfer, or follow up visit.