Medicare patient in for screening colonoscopy, the physician documents doing a random biopsy that came back as benign mucosa.

Am I correct in thinking that this should still be coded as G0121? A "diagnostic colonoscopy with biopsy (45380)" is finding a lesion or polyp to biopsy for diagnostic reasons. Since there is no reason, but "random" biopsy, there is nothing to lead me to diagnostic. Therefore, still screening?

Thank you in advance.