Men's Lab Testing

Understanding Men's Testosterone Lab Testing

Recognizing Low Testosterone Symptoms

Low testosterone can affect multiple aspects of your health and wellbeing. Common symptoms include:

  • Difficulty achieving or maintaining erections
  • Decreased interest in sex
  • Loss of muscle mass
  • Persistent fatigue and low energy
  • Increased body fat, especially around the midsection
  • Reduced bone density
  • Thinning body hair
  • Feelings of depression or mood changes
  • Development of breast tissue

Don't ignore these symptoms. While they don't automatically mean you have low testosterone—they could indicate other medical conditions—they're worth investigating with proper testing.

Getting Tested for Low Testosterone

The Right Tests at the Right Time

Blood tests are the only accurate way to measure testosterone levels. We don't recommend saliva tests as they're unreliable.

Best timing: Schedule your blood draw between 7 and 10 a.m., when testosterone levels peak. We typically confirm low results with a second test to ensure accuracy.

NRG Clinic's Comprehensive Hormone Panel

At NRG Clinic, we offer the most comprehensive hormone test in the market through our partnership with Labcorp. Our Men's Complete Hormone Test includes:

Hormone Markers:

  • Free and total testosterone
  • Estrogen levels
  • Sex hormone binding globulin (SHBG)
  • Follicle-stimulating hormone (FSH)
  • Luteinizing hormone (LH)
  • Prolactin

Thyroid Function:

  • Thyroid test with Free T3

Metabolic and General Health:

  • Complete blood count (CBC)
  • Complete metabolic panel (CMP)
  • Lipid panel

Men's Health Specific:

  • Prostate specific antigen (PSA)

Understanding Your Test Results

What's the difference between total and free testosterone?

Your body contains testosterone in two forms: bound and free. The vast majority—over 98%—is bound to proteins in your bloodstream, while less than 2% circulates freely. Only the free testosterone can actually work in your body.

Here's why: After your testes produce testosterone, it enters your bloodstream where it attaches to carrier proteins. These proteins help transport testosterone throughout your body and prevent it from being eliminated too quickly. The main carriers are sex hormone binding globulin (SHBG) and albumin.

While bound testosterone isn't biologically active, there's an important distinction: testosterone attached to albumin releases easily and becomes readily available for your tissues to use. We call this "bioavailable." In contrast, testosterone bound to SHBG stays locked up and unavailable.

Why this matters: Your free testosterone level can be just as important—or even more important—than your total level. We've seen patients with normal total testosterone but low free testosterone, and vice versa. That's why we test both.

What Are Normal Testosterone Levels?

Total Testosterone

For men, typical total testosterone ranges from approximately 300 to 1,050 ng/dL. Different medical organizations suggest various thresholds for treatment:

  • The Endocrine Society notes that 300 ng/dL is a common threshold where many men experience symptoms
  • American Association of Clinical Endocrinologists suggests men with symptoms and levels below 200 ng/dL may benefit from therapy
  • European Association of Urology uses 350 ng/dL as their guideline
  • Japanese Urological Association recommends focusing primarily on free testosterone rather than total

Free Testosterone

Normal free testosterone typically ranges from 5 to 21 ng/dL in men. However, different labs use different testing methods, so your results may look different depending on which assay is used. Always compare your results to the reference range provided by the specific laboratory that processed your test.

Important Considerations About "Normal"

The range is wide. One man can have three to four times the testosterone of another man, and both fall within "normal" limits. This is why your individual symptoms matter so much.

Your personal baseline matters. Some men start experiencing low testosterone symptoms even when their levels are technically normal. Why? Because their levels have dropped significantly from their personal peak. We've worked with patients who felt symptomatic at 450 ng/dL because they'd previously maintained levels around 800 ng/dL.

Age changes everything. Testosterone naturally declines with age—total levels drop about 30% between ages 25 and 75, while free testosterone plummets by nearly 50%. Unfortunately, there's no age-adjusted "normal" range, which is one reason why low testosterone becomes increasingly common as men get older.

At NRG Clinic, we evaluate each patient individually, considering your age, symptoms, overall health, and testosterone levels together to determine the best treatment approach.

Understanding the Cause: Primary vs. Secondary Hypogonadism

If your tests confirm low testosterone, we'll investigate the underlying cause. There are two main types:

Primary Hypogonadism

The testes themselves aren't producing enough testosterone, even though the signaling system is working correctly. This is a testicular issue.

Secondary Hypogonadism

The problem lies elsewhere in your endocrine system—typically the hypothalamus or pituitary gland isn't properly signaling your testes to produce testosterone. Your testes could function normally if they received the right signals.

How We Determine the Cause

We measure LH and FSH levels, which are the hormones that tell your testes to produce testosterone. Here's what different patterns tell us:

  • Low testosterone + Low LH/FSH = Likely secondary hypogonadism (signaling problem)
  • Low testosterone + High LH/FSH = Likely primary hypogonadism (testicular problem)

Investigating Secondary Causes

If you have secondary hypogonadism, we'll look deeper:

  • Prolactin levels: Elevated prolactin suppresses testosterone production and can cause breast enlargement and erectile dysfunction
  • Thyroid function: Hypothyroidism suppresses LH secretion, which in turn reduces testosterone production
  • Estrogen levels: Imbalanced estrogen can affect testosterone production and overall hormone health
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