Hall and colleagues1 report that 88% of men with “symptomatic androgen deficiency” went untreated. This disease was defined as a serum total testosterone level lower than 300 ng/dL (to convert to nanomoles per liter, multiply by 0.0347) and the presence of symptoms.
The choice of this level is a bit arbitrary (low reference value for total testosterone ranged from 130 to 450 ng/dL in one study),2 is presumably based on a mean (SD) value, and is not discussed in the article. In the authors' words, the symptoms are “less specific”: low libido and 2 or more of sleep disturbance, depressed mood, lethargy, or diminished physical performance would qualify.
Finucane TE. Men, Androgen Deficiency, and Pharmaceutical Promotion. Arch Intern Med. 2009;169(1):87-89. doi:10.1001/archinternmed.2008.555