Venous Dopplers Lower Ext

Are we coding correct? Medicare patient comes in for Venous Doppler Bilateral lower extremities and Arterial Doppler. Symptoms are pain in legs, pain while walking, history of PVD/PAD, claudication and stents, the CPT's we use are 93965-TC, 93970-TC and 93925-TC. Medicare always denies 93970-TC for more information and still deny after we send the info. What are we doing wrong?