Testosterone Therapy: Which Blood Tests Are Commonly Used?

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Blood tests for testosterone therapy serve two different purposes: confirming that testosterone treatment is appropriate in the first place, and monitoring whether treatment is working safely after it starts. The most common labs include total testosterone, sometimes free testosterone with sex hormone-binding globulin (SHBG), complete blood count (CBC) with hemoglobin and hematocrit, and prostate-specific antigen (PSA) for patients in whom prostate monitoring applies. Depending on the reason for therapy and the person’s health history, clinicians may also order LH, FSH, prolactin, estradiol, lipid testing, glucose or A1c, liver and kidney markers, and fertility-related testing.

Blood tests before starting testosterone therapy

Before prescribing testosterone, clinicians generally look for both compatible symptoms and consistently low measured testosterone. The Endocrine Society testosterone therapy guideline emphasizes appropriate diagnostic workup and monitoring rather than treating a single number in isolation. The American Urological Association guideline similarly frames testosterone deficiency as a clinical and biochemical diagnosis.

Test	Why it is used	Common timing
Total testosterone	Main test for confirming low testosterone and later checking whether the dose reaches the intended range.	Usually early morning for diagnosis; repeated on a separate day if low.
Free testosterone, SHBG, albumin	Helps when total testosterone is borderline or SHBG may be abnormal. Free testosterone may be measured directly or calculated from total testosterone, SHBG, and albumin.	Often baseline; sometimes repeated if clinical picture and total testosterone do not match.
LH and FSH	Help distinguish primary testicular causes from secondary pituitary or hypothalamic causes. FSH is also relevant when fertility is a concern.	Often after a low testosterone result is confirmed.
Prolactin	Can help evaluate pituitary-related causes, especially when LH is low or low-normal.	Baseline when indicated.
CBC with hemoglobin and hematocrit	Checks red blood cell concentration before treatment and provides a safety baseline.	Baseline before treatment, then repeated during therapy.
PSA	Assesses prostate-related risk in patients for whom prostate monitoring is appropriate.	Baseline in many men over 40 or in higher-risk groups, depending on guideline and clinician judgment.
Estradiol	Useful with gynecomastia, breast tenderness, use of aromatase inhibitors, or when a clinician wants a baseline.	Baseline or symptom-triggered.
Lipid panel, glucose, A1c, CMP	Assesses cardiovascular and metabolic context; may be used to monitor related risks or other medications.	Baseline and periodically based on risk factors.

Total testosterone: the anchor test

Total testosterone measures bound and unbound testosterone in blood. It is the most common testosterone test and is usually the first lab ordered when evaluating symptoms such as low libido, erectile dysfunction, infertility, anemia without another clear cause, loss of muscle mass, or low bone density. MedlinePlus explains that total testosterone measures both bound and free testosterone, while free testosterone measures only the unattached portion.

A single low value is usually not enough to justify treatment because testosterone varies by time of day, sleep, illness, calorie restriction, medications, and laboratory method. Many clinicians repeat a low early-morning level before diagnosing testosterone deficiency. This is especially important when a result is near the lower limit of the lab’s reference range.

Free testosterone, SHBG, and albumin

Most testosterone in blood is attached to proteins, especially SHBG and albumin. When SHBG is unusually high or low, total testosterone may not reflect the amount of testosterone that is biologically available. Free testosterone testing may be helpful when total testosterone is borderline, symptoms are strong, or SHBG-altering conditions are present. Examples include obesity, aging, thyroid disease, liver disease, HIV, some seizure medicines, glucocorticoids, and certain endocrine disorders.

Free testosterone can be measured by specialized methods or calculated using total testosterone, SHBG, and albumin. The method matters. Direct analog free testosterone immunoassays have known limitations, while equilibrium dialysis or validated calculated free testosterone is generally preferred when accuracy is important. Patients should avoid comparing free testosterone numbers across labs without checking units, method, and reference interval.

LH, FSH, and prolactin: finding the “why”

LH and FSH are pituitary hormones that help regulate testosterone production and sperm production. If testosterone is low and LH/FSH are high, the pattern can suggest primary testicular dysfunction. If testosterone is low and LH/FSH are low or inappropriately normal, the pattern can suggest secondary hypogonadism involving the pituitary or hypothalamus. The Endocrine Society guideline recommends distinguishing primary from secondary hypogonadism by measuring LH and FSH in men with hypogonadism.

Prolactin is commonly added when secondary hypogonadism is suspected. A high prolactin result can point toward medication effects, hypothyroidism, kidney disease, pituitary disorders, or other causes that may need evaluation before testosterone is considered. This is one reason direct-to-consumer testosterone screening can be incomplete if it stops at a single testosterone number.

Blood tests used during testosterone therapy

Once therapy starts, monitoring focuses on three questions: Is the testosterone level in the intended range? Are symptoms improving? Are safety markers changing in a concerning way? The answer depends partly on the formulation, dose, age, prostate risk, fertility goals, sleep apnea risk, cardiovascular risk factors, and baseline lab values.

Monitoring test	What clinicians are watching for	Typical action if abnormal
Total testosterone	Low levels may mean underdosing, missed doses, poor absorption, or wrong draw timing. High levels may increase side-effect risk.	Confirm timing and adherence; adjust dose, interval, or formulation if needed.
CBC: hemoglobin/hematocrit	Excess red blood cell concentration, sometimes called erythrocytosis or polycythemia.	Evaluate causes, consider dose reduction or holding therapy; many guidelines flag hematocrit above 54%.
PSA	Unexpected PSA rise or values needing urology evaluation.	Repeat to confirm; consider urology referral based on PSA level, rise from baseline, exam, and risk factors.
Estradiol	Breast tenderness, gynecomastia, fluid retention, or monitoring while using aromatase inhibitors.	Assess symptoms first; avoid treating a number alone unless clinically appropriate.
Lipids, glucose, A1c	Metabolic and cardiovascular risk context.	Lifestyle, primary care management, medication review, or therapy adjustment based on overall risk.
CMP or liver/kidney markers	General medical monitoring and medication safety; particularly relevant with some oral drugs or comorbidities.	Evaluate non-testosterone causes; adjust medications if needed.

CBC, hemoglobin, and hematocrit

CBC is one of the most important safety tests for testosterone therapy because testosterone can stimulate red blood cell production. Hematocrit is the percentage of blood volume occupied by red blood cells; hemoglobin is the oxygen-carrying protein inside them. If these rise too far, blood viscosity increases and the clinician must consider risk factors such as smoking, dehydration, high altitude, lung disease, and obstructive sleep apnea.

The Endocrine Society monitoring table recommends checking hematocrit at baseline, 3 to 6 months after starting therapy, and then annually, with action if hematocrit is above 54%. The AUA guideline also recommends baseline hemoglobin/hematocrit before offering therapy and ongoing monitoring to keep hematocrit below 54%. These numbers are not meant for self-adjusting medication; they are thresholds for clinician review.

PSA and prostate-related monitoring

PSA is a protein produced by prostate tissue. It can rise for reasons that include benign prostate enlargement, inflammation, infection, recent ejaculation, procedures, and prostate cancer. Testosterone therapy may increase PSA modestly in some hypogonadal men, and monitoring is intended to identify changes that require evaluation without assuming every PSA change is cancer.

The Endocrine Society recommends discussing prostate monitoring with appropriate patients and, for those who choose monitoring, checking PSA and performing prostate evaluation before treatment and again 3 to 12 months after starting, then following standard prostate cancer screening guidance. The same guideline recommends urology consultation for a confirmed PSA increase greater than 1.4 ng/mL within 12 months, a confirmed PSA above 4.0 ng/mL, or an abnormal prostate exam. The AUA guideline states that PSA should be measured before testosterone therapy in patients over 40 to reduce the risk of prescribing testosterone to someone with occult prostate cancer.

Estradiol: useful, but not always routine

Some testosterone is converted to estradiol by aromatase enzymes. Estradiol is important for bone and sexual health, so the goal is not necessarily to drive it as low as possible. Estradiol testing is most useful when symptoms suggest it is clinically relevant, such as breast tenderness or gynecomastia, or when a patient is taking an aromatase inhibitor. The AUA guideline notes estradiol measurement for testosterone-deficient patients with baseline gynecomastia and for patients who develop breast symptoms while on therapy.

Because symptoms and lab methods vary, estradiol should be interpreted with the clinical picture. Treating estradiol solely because it is outside a preferred online “optimal range” can create new problems, including low estradiol symptoms and potential bone-health concerns.

Lipids, glucose, A1c, liver, and kidney tests

Not every testosterone guideline requires a full metabolic panel at every follow-up, but these tests are commonly used in real-world care. A lipid panel measures cholesterol patterns that contribute to cardiovascular risk. Fasting glucose and hemoglobin A1c assess diabetes risk or control. A comprehensive metabolic panel can include liver enzymes, kidney markers, electrolytes, albumin, and glucose.

These tests are especially relevant for patients with diabetes, obesity, hypertension, sleep apnea, cardiovascular disease, liver disease, kidney disease, or multiple medications. They can also help distinguish symptoms caused by low testosterone from symptoms caused by thyroid disease, anemia, diabetes, depression, medication effects, poor sleep, or other common conditions.

Gender-affirming testosterone therapy

For transmasculine and some nonbinary patients using testosterone as gender-affirming hormone therapy, the lab categories overlap but the goals and reference ranges are individualized. The Endocrine Society guideline for gender-dysphoric/gender-incongruent persons highlights monitoring testosterone levels, hematocrit or hemoglobin, weight, blood pressure, and lipids, with attention to adverse effects such as erythrocytosis. Cancer screening depends on organs present, age, risk factors, and surgical history. Patients should use a clinician experienced in gender-affirming care when possible, because interpretation may differ from hypogonadism protocols for cisgender men.

When to draw testosterone labs

Timing is one of the most common reasons testosterone results are misleading. For diagnosis, morning draws are preferred because testosterone often peaks earlier in the day. MedlinePlus describes morning collection, often between 7 and 10 a.m., for testosterone levels testing. Acute illness, poor sleep, heavy alcohol use, severe calorie restriction, and some medications can temporarily lower levels, so clinicians may delay testing until a person is back to baseline health.

During treatment, timing depends on the product:

• Testosterone cypionate or enanthate injections: clinicians often choose a consistent point in the injection cycle, such as midway between injections or just before the next dose, depending on what question they are trying to answer.
• Long-acting testosterone undecanoate injections: levels are commonly assessed near the end of the dosing interval.
• Gels: levels are usually checked after the patient has used the gel long enough to reach steady use, with timing relative to application specified by the prescriber.
• Patches: blood draw timing is based on hours after patch application.
• Pellets: levels are often checked later in the dosing interval to decide when another insertion is needed.
• Oral testosterone undecanoate: absorption depends on food and product instructions, so timing should follow the prescribing plan.

The key is consistency. A testosterone result drawn at a trough cannot be compared directly with a peak result unless the clinician knows when it was collected.

How results are interpreted

Testosterone therapy blood work is interpreted against the treatment goal, the lab’s reference interval, the method used, and the patient’s symptoms. For adult men with hypogonadism, the Endocrine Society describes aiming for testosterone concentrations in the mid-normal range for healthy young men, while the AUA recommends follow-up levels to ensure target levels are achieved and maintained. In practice, clinicians also consider side effects, fertility goals, sexual function, energy, mood, anemia, bone health, and whether symptoms improved after levels normalized.

Low on-treatment testosterone may reflect underdosing, missed doses, application problems with gel, injection timing, drug interactions, obesity-related distribution changes, or lab variation. High on-treatment testosterone may occur when injections peak too high, doses are too large, intervals are too long, or a blood draw was taken at the wrong point in the cycle. Dose decisions should not be based on a single unexpected number without confirming the context.

Hematocrit deserves special attention. A rising hematocrit may be managed by reducing dose, changing injection frequency, switching formulation, evaluating sleep apnea or lung disease, addressing smoking, or temporarily holding therapy. Therapeutic phlebotomy is sometimes used, but it should not substitute for identifying why hematocrit is rising.

PSA interpretation is also contextual. A modest PSA change may be repeated to confirm it is real, while a larger confirmed rise, a PSA above a threshold, or an abnormal exam may prompt urology referral. Patients should tell the ordering clinician about urinary symptoms, prostatitis history, recent urinary procedures, cycling, ejaculation, or infections that may affect PSA timing.

Cost and ordering considerations

The cost of testosterone therapy lab monitoring varies widely. A single total testosterone test is usually less expensive than a broad hormone and metabolic panel, but the effective cost to the patient may include a lab draw fee, a clinician visit, a telehealth follow-up, repeat testing, and any required authorization fee. Insurance may cover testing when medically necessary, but coverage can depend on diagnosis codes, network labs, prior authorization, and whether testing is ordered by an in-network clinician.

For cash-pay testing, compare the total cost rather than the advertised test price alone. Ask whether the price includes the blood draw, physician order, result report, taxes or service fees, and repeat testing if the sample is rejected. Also check whether the test is available in your state and whether results can be used by your treating clinician. Some direct-access labs can provide useful screening information, but a prescriber may still require repeat or confirmatory testing through a specific lab before starting or changing therapy.

A practical approach is to ask your clinician three questions before each lab order: Which results will change the treatment plan? When should the sample be drawn relative to my dose? And what result would require urgent follow-up or holding treatment? These questions keep testing focused on decisions rather than collecting numbers without a plan.

Practical checklist before your next testosterone lab draw

• Confirm whether the test is for diagnosis, dose adjustment, or safety monitoring.
• Ask whether you need a morning draw or dose-specific timing.
• Bring the exact testosterone product, dose, route, and dosing schedule.
• List all medications and supplements, including biotin, steroids, opioids, finasteride, aromatase inhibitors, SERMs, hCG, and thyroid medication.
• Tell the clinician about sleep apnea, smoking, high-altitude residence, dehydration, prostate symptoms, fertility goals, and recent illness.
• Use the same lab when possible for serial comparisons, especially for testosterone and PSA.
• Do not stop or change prescribed testosterone solely because of an unexpected lab value unless your clinician instructs you to do so.

 

FAQs

What blood tests are commonly ordered before testosterone therapy?

Common baseline tests include early-morning total testosterone repeated on a separate day, free testosterone with SHBG and albumin when indicated, LH and FSH, prolactin when secondary hypogonadism is suspected, CBC with hemoglobin and hematocrit, PSA for appropriate patients, and selected metabolic tests such as lipids, glucose or A1c, and a comprehensive metabolic panel.

How often should blood work be checked while on testosterone therapy?

Schedules vary. Endocrine Society guidance for men with hypogonadism includes testosterone and hematocrit monitoring about 3 to 6 months after starting, at 12 months, and then annually. AUA guidance commonly checks testosterone every 6 to 12 months once stable, with hematocrit monitoring to keep levels below 54%. Clinicians may test more often during dose changes or when risk factors are present.

Do I need free testosterone or just total testosterone?

Total testosterone is the main starting test. Free testosterone is useful when total testosterone is borderline, symptoms and total testosterone do not match, or SHBG may be abnormal. The best free testosterone method depends on the lab, and results should be interpreted with the reference interval and clinical context.

Why do clinicians order CBC for testosterone therapy?

CBC measures hemoglobin and hematocrit. Testosterone can increase red blood cell production, and high hematocrit may increase safety concerns. A hematocrit above 54% is a common action threshold in major guidelines.

Should estradiol be tested every time?

Not necessarily. Estradiol is most useful when there are breast symptoms, gynecomastia, use of aromatase inhibitors, unexplained fluid retention, or a clinician wants a baseline. It is usually not helpful to treat estradiol as an isolated number without symptoms and a clear plan.

Can testosterone therapy affect blood pressure or cardiovascular monitoring?

Yes, monitoring may include blood pressure and cardiovascular risk review. In 2025, the FDA announced class-wide testosterone labeling changes that included adding product-specific or class warnings about increased blood pressure while removing boxed-warning language related to increased adverse cardiovascular outcomes after review of newer evidence. Blood tests do not replace blood pressure checks and risk-factor management.

Can I order testosterone therapy blood tests myself?

In many U.S. states, adults can self-order certain lab tests through direct-access services, but rules and availability vary. Self-ordered labs can help you understand your numbers, but treatment decisions should be made with a licensed clinician who can interpret results, evaluate risks, and manage abnormal findings.

Sources

• Endocrine Society: Testosterone Therapy for Hypogonadism Guideline Resources
• Bhasin S, et al. Testosterone Therapy in Men With Hypogonadism: An Endocrine Society Clinical Practice Guideline
• American Urological Association: Evaluation and Management of Testosterone Deficiency Guideline
• MedlinePlus: Testosterone Levels Test
• U.S. Food and Drug Administration: Class-wide labeling changes for testosterone products
• Endocrine Society: Endocrine Treatment of Gender-Dysphoric/Gender-Incongruent Persons