Should we Order Testosterone Labs for Erectile Dysfunction?
Before we get into the case, there are different testosterone tests to order - this post will focus on total testosterone.
A note on total testosterone vs. free testosterone:
(1)
Case: you are seeing a 45 year-old male patient requesting testosterone bloodwork because he has been experiencing erectile dysfunction.
Testosterone testing is often requested by patients experiencing erectile dysfunction (ED), among other reasons.
Question: Should we routinely order testosterone in male patients with erectile dysfunction?
Answer: Only if there are signs and symptoms of hypogonadism (testosterone deficiency) (2, 3). Why? Let’s get into it!
What is erectile dysfunction?
It is the inability to achieve or maintain an erection sufficient for satisfactory sexual performance, and is highly prevalent in North America (4). It is a presentation with a long lost of differential diagnoses.
What are our differential buckets for ED?
I like to use the mechanism framework.
(4)
When should we order testosterone in male patients with ED?
Total testosterone should be ordered if a hormonal etiology of ED (i.e. hypogonadism or testosterone deficiency) is suspected (4). In other words, if your pre-test probability for testosterone deficiency is moderate to high, it is worthwhile ordering. Also consider ordering total testosterone if 1-2 trials of phosphodiesterase type-5 inhibitors (e.g. sildenafil, tadalafil) has failed (4).
BOTTOM LINE: Only order total testosterone in male patients with erectile dysfunction if there are signs and symptoms specific / strongly supportive of testosterone deficiency.
What causes hypogonadism?
There are primary and secondary causes.
Primary hypogonadism (testicles are not producing hormones): persistently low testosterone measurements with above-normal LH levels. Some causes include Klinefelter syndrome, undescended testicles, mumps orchitis, hemochromatosis, cancer treatment, and normal aging (5).
Secondary hypogonadism (pituitary is not producing hormones): is characterized by low serum testosterone with normal or low LH levels. Some causes include Kallman syndrome, pituitary disorders, HIV, obesity, surgery, trauma, and stress-induced hypogonadism (5).
When should we suspect testosterone deficiency as the cause for ED?
Look for signs & symptoms specific to testosterone deficiency: loss of body hair (axillary, facial, pubic), very small testes (<6ml) (1).
Look for signs & symptoms that are supportive of testosterone deficiency: breast discomfort, gynecomastia, infertility, low sperm count, low bone density, loss of height, hot flushes, sweats, decrease in libido, erectile dysfunction, decreased frequency of morning erections or spontaneous erections (1).
Signs & symptoms that are NOT specific of testosterone deficiency: fatigue, depression, poor concentration or memory, sleep disturbance, anemia, decreased muscle mass or strength, increased BMI (1).
Back to the case: after a thorough history and physical exam, there are no specific or supportive signs or symptoms of testosterone deficiency. Other risk factors for ED identified include pre-diabetes and significant psychosocial stress. He asks again whether testosterone levels should be checked.
What is the initial test of choice for male patients with suspected testosterone deficiency? total testosterone (1,4,5).
When should we check total testosterone levels in males with ED? Testosterone should be checked if there are specific and/or supportive clinical signs and symptoms of testosterone deficiency. That way, if testosterone biochemical levels are low, this will correlate clinically, and testosterone therapy can be considered. Testosterone therapy should only be considered for patients who exhibit signs and symptoms consistent with clinical hypogonadism. In the absence of symptoms—even if total testosterone levels are low—treatment is not recommended (2,5).
Practical Tips for Ordering Total Testosterone
Early morning (8 AM to 10 AM, or within 3 hours of waking) - due to diurnal variation of testosterone (1)
Ideally fasting
Avoid if the patient is jet-lagged or acutely ill as this can skew results
If the initial level is low, a second measurement is recommended to confirm hypogonadism (5).
If levels are repeated, go to the same lab, as testing and lab reference ranges vary
Total Testosterone Test limitations
Specificity concerns: Total testosterone levels are not highly specific for diagnosing hypogonadism, particularly when levels are between 9.7-12.1 nmol/L (280 and 350 ng/dL) (i.e. risk of false positive results) (5). A total testosterone level above 12.1-13.8nmol/L (350-400 ng/dL) is generally needed to reliably predict normal free testosterone level (6).
Results are not always accurate in older men (due to SHBG changes), with obesity, and chronic illness. Results may not reflect bioavailable testosterone, which is more correlated with symptoms (6).
Testosterone levels fluctuate throughout the day, there are monthly variations, and levels naturally decline with age (especially after age 30).
Certain lifestyle factors like sleep, diet, stress, exercise, and health conditions affect testosterone levels.
All of these factors can make it difficult to interpret results!
Back to the case: you decide against ordering total testosterone, because there are no specific signs or symptoms of testosterone deficiency, and instead investigate other etiologies of ED.
Key take home point: Total testosterone is a lab test often requested by patients experiencing erectile dysfunction. However, if a patient does not have signs or symptoms suggestive of testosterone deficiency, treatment is not recommended—even if biochemical levels are low. As with any test, it’s important to ask: will this result change my management plan?
ReferencesBritish Columbia Guidelines. Testosterone Testing - Protocol. 2022. [Internet]. [cited 2025 June 24]The Endocrine Society. Testosterone Therapy in Adult Men with Androgen Deficiency Syndromes: An Endocrinology Society Clinical Practice Guideline [Internet]. 2010 [cited 2025 June 24].Choosing Wisely. Urology - Five Tests to and Treatments to Question [Internet]. 2024. [cited 2025 June 24].Domes, T. ., Najafabadi, B. T. ., Roberts, M. ., Campbell, J. ., Flannigan, R. ., Bach, P. ., … Violette, P. D. . (2021). Canadian Urological Association guideline: Erectile dysfunction. Canadian Urological Association Journal, 15(10), 310–22. https://doi.org/10.5489/cuaj.7572Sizar O, Leslie SW, Schwartz J. Male Hypogonadism. [Updated 2024 Feb 25]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2025 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK532933/Anawalt BD, Hotaling JM, Walsh TJ, Matsumoto AM. Performance of total testosterone measurement to predict free testosterone for the biochemical evaluation of male hypogonadism. J Urol. 2012 Apr;187(4):1369-73. doi: 10.1016/j.juro.2011.11.095. Epub 2012 Feb 15. PMID: 22341266; PMCID: PMC10368284.