DEFY Blog
search the defy medical knowledge base:"Effective July 17, 2017 the LabCorp reference range for total testosterone measurement in adult males will be changing (DECREASING) to 264 - 916 ng/dL (previously 348 - 1197 ng/dL). Please note the METHODOLOGY for the assay is not changing in any way, only the reference range is changing.
Reasons for this change, as cited by LabCorp, include pressure from the CDC for standardization (harmonization) across labs of testosterone reference range and, ultimately, a different study/patient population used for the two ranges. The low end cut-off for both ranges is the bottom 2.5 percentile of the patient population. As stated by LabCorp, "the lower numeric range in the new standardized reference interval reflects a difference in average subjects with higher BMIs as well as harmonization to the CDC reference method". This is essentially stating higher BMIs (overweight) is the new norm and the new testosterone reference range is taking this into account with a "lower numeric range". Indeed, this is a step AWAY from normal, let alone optimal.
As I already know what OPTIMAL testosterone levels are for most males (based upon treating over 10,000 of them), this simple change in reference range is not going to negatively impact our patients. However, I fear this change is going to lead to even more men walking in to their PCP or other provider with classic hypogonadal symptoms but T levels "in range" (now all the way down to 264!) and being told they're "normal" and given an SSRI + Viagra and sent out the door to continue to suffer."- Justin Saya, M.D.