Normal testosterone levels for 26 year old male?

Anyone know what's normal for a 26 year old??? The test normal range is 280+ but this is for all men of all ages. My husband is only 26 and his was just 298. This seems low to me and I'd like them to help us raise his testosterone, it's the weekend so I cannot discuss the results with his Dr yet. But he stated he was sure my husband's levels would be just fine, only tested at my request. My husband has all the symptons of low testosterone plus our secondary infertility issues.