Nelson Vergel
Founder, ExcelMale.com
Validity of Midday Total Testosterone Levels in Older Men with Erectile Dysfunction; Welliver R, Wiser H, Brannigan R, Feia K, Monga M, Köhler T; Journal of Urology (Feb 2014)
INTRODUCTION: Based on studies demonstrating the circadian rhythmicity of testosterone levels, the optimal time of day to draw total testosterone (TT) in men has classically been reported as between 8 and 11 AM. However, further studies have demonstrated that the circadian rhythmicity of testosterone levels becomes blunted with age.
METHODS: Charts of 2,569 men presenting with erectile dysfunction (ED), were retrospectively reviewed for TT and draw times and were compared by age group. Men were grouped to: less than 40, and then by 5 year groupings. TT was analyzed for variability over the most common draw time hours (7 AM - 2 PM).
RESULTS: The mean TT for 7-9 AM versus 9 AM-2 PM were both clinically and statistically different only for men in the age groups of<40 and 40-44, with mean TT differences of 207 ng/dL [95% CI 98-315 p = 0.0004], and 149 ng/dL [95% CI 36-262 p = 0.01]respectively. All other groupings did not demonstrate both a clinically and statistically significant difference between those time periods.
CONCLUSION: A TT level in men with ED who are younger than 45 years should be drawn as close to 7 AM as possible as a statistically and a clinically relevant drop in testosterone levels will occur over the course of the day. Men older than age 45 years with ED can have their TT drawn at any time before 2 PM without fear of misleading results.
INTRODUCTION: Based on studies demonstrating the circadian rhythmicity of testosterone levels, the optimal time of day to draw total testosterone (TT) in men has classically been reported as between 8 and 11 AM. However, further studies have demonstrated that the circadian rhythmicity of testosterone levels becomes blunted with age.
METHODS: Charts of 2,569 men presenting with erectile dysfunction (ED), were retrospectively reviewed for TT and draw times and were compared by age group. Men were grouped to: less than 40, and then by 5 year groupings. TT was analyzed for variability over the most common draw time hours (7 AM - 2 PM).
RESULTS: The mean TT for 7-9 AM versus 9 AM-2 PM were both clinically and statistically different only for men in the age groups of<40 and 40-44, with mean TT differences of 207 ng/dL [95% CI 98-315 p = 0.0004], and 149 ng/dL [95% CI 36-262 p = 0.01]respectively. All other groupings did not demonstrate both a clinically and statistically significant difference between those time periods.
CONCLUSION: A TT level in men with ED who are younger than 45 years should be drawn as close to 7 AM as possible as a statistically and a clinically relevant drop in testosterone levels will occur over the course of the day. Men older than age 45 years with ED can have their TT drawn at any time before 2 PM without fear of misleading results.
