Only way to truly verify is to do an extensive test yourself where you record the SMART values, zero out the drive twice, then compare the SMART values again. It's too much work for most, so I usually just say to back up your most precious bits 1st. Then do either an image backup or backup the rest of your stuff. Then run the manufacturer's diagnosis utility. If it says the same thing, then RMA or replace it. If you're lucky the manufacturer's utility can remap new sectors to replace bad ones and your drive can be usable again so best of luck.