Which blood tests for TRT, before and during
Two guidelines set the TRT blood test schedule in the US: the Endocrine Society's 2018 guideline on testosterone therapy and the American Urological Association's testosterone deficiency guideline (2018, validity confirmed 2024). They agree on the core: testosterone to confirm the dose is right, hematocrit because testosterone raises red cell counts, and PSA in men in the prostate screening age range.
| Marker | Why it matters | What a result suggests | On SiPhox |
|---|---|---|---|
| Total testosterone | Confirms the dose reaches the target | AUA aims for the middle third of the normal range, about 450 to 600 ng/dL; Endocrine Society says mid-normal | Hormone Focus, Longevity (men), Ultimate 360, GLP (men) |
| Free testosterone and SHBG | Useful when SHBG is high or low | Explains a total T that does not match how you feel | Longevity (men), Thyroid Focus, Hormone Focus, Ultimate 360, GLP |
| Hematocrit and hemoglobin | Testosterone stimulates red cell production | Above 54%: Endocrine Society says stop until it falls to a safe level | Longevity, Heart & Metabolic, Ultimate 360, GLP; or CBC add-on ($45) |
| PSA | Testosterone can unmask prostate disease | Rise over 1.4 ng/mL within 12 months or a confirmed PSA over 4.0: urology referral | Hormone Focus (men), Ultimate 360 (men) |
| Estradiol | Testosterone converts to estradiol | AUA: measure if there are breast symptoms; routine targets are not set by either guideline | Hormone Focus, Ultimate 360, GLP |
| LH and FSH | Before TRT, show the cause; on TRT, show suppression | Suppressed LH and FSH on TRT are expected and mean sperm production is suppressed too | Hormone Focus, Ultimate 360 |
| Prolactin | Before TRT, when LH is low or normal | High prolactin needs a pituitary workup first | Hormone Focus, Ultimate 360 |
| Lipids, HbA1c, liver enzymes | Not required by the guidelines, but a sensible yearly check | Baseline for heart and metabolic health | Longevity, Heart & Metabolic, Ultimate 360, GLP |
The TRT monitoring schedule
Source: Endocrine Society 2018 testosterone therapy guideline. After year one, testosterone and hematocrit are checked yearly; the AUA checks testosterone every 6 to 12 months.
| When | Endocrine Society | AUA |
|---|---|---|
| Before starting | Two morning total T; hematocrit; PSA and prostate exam for men 55 to 69, or 40 to 69 at higher risk, who choose monitoring | Two morning total T under 300 ng/dL; LH; prolactin if LH low or normal; hemoglobin and hematocrit; PSA in men over 40; estradiol if breast symptoms |
| 3 to 6 months | Testosterone (aim mid-normal); hematocrit | Testosterone to confirm a therapeutic level |
| 3 to 12 months | PSA and prostate exam; review symptoms and side effects | Follow-up visit |
| Every year after | Testosterone, hematocrit, symptoms; PSA per screening guidelines | Testosterone every 6 to 12 months; hematocrit monitored |
| Action levels | Hematocrit above 54%: stop until safe. PSA up more than 1.4 ng/mL in 12 months, a confirmed PSA above 4, or a prostate abnormality: urology | Adjust dose toward 450 to 600 ng/dL |
The Endocrine Society also recommends against testosterone therapy in men planning a pregnancy in the near term, because it suppresses sperm production. If fertility matters, raise it before the first dose. For how low testosterone is diagnosed in the first place, see our low testosterone blood test guide.
Why hematocrit is the number to watch
Testosterone stimulates red blood cell production, and the Endocrine Society lists a significantly higher rate of erythrocytosis (hematocrit above 54%) among the adverse effects seen in testosterone trials. Thicker blood is the concern, which is why 54% is treated as a stop sign rather than a number to watch. Two things push a reading up without any change in dose: dehydration and living at altitude. A capillary hematocrit, like the calculated value SiPhox reports, can also differ from a venous one, so any result approaching 54% should be repeated on a venous CBC before a decision is made.
When to draw blood on TRT
- Injections (cypionate or enanthate): the Endocrine Society measures testosterone midway between injections. Many prescribers also ask for a trough, just before the next dose. Pick one and keep it the same.
- Gels, patches, pellets and oral forms each have their own timing; follow your prescriber's instructions.
- Same day of the week and time of day every test, so changes reflect the dose, not the timing.
- Hydrate normally. Dehydration concentrates blood and nudges hematocrit up. For a SiPhox draw, drink about 16 oz of water beforehand, which also helps the device fill.
- Tell the reader about biotin, which the FDA warns can interfere with hormone immunoassays.
Worked example: month four on weekly injections
Illustrative numbers. A 52-year-old on weekly testosterone cypionate tests mid-week, four months in. His baseline PSA was 0.8 ng/mL and hematocrit 45%.
| Marker | Result | Reading |
|---|---|---|
| Total testosterone | 780 ng/dL | Above the AUA 450 to 600 ng/dL target |
| Hematocrit | 51% | Up 6 points; below the 54% stop level but rising |
| PSA | 1.3 ng/mL | Up 0.5 ng/mL, under the 1.4 ng/mL referral rise |
| Estradiol | 48 pg/mL | Higher than baseline; no breast symptoms |
Nothing here is an emergency, but the pattern (testosterone above target, hematocrit climbing) is exactly what monitoring is for. His prescriber may lower the dose or split it, then recheck testosterone and hematocrit in a few months. Because SiPhox reports a hematocrit calculated from capillary hemoglobin, a value near 54% should be confirmed with a venous CBC before any decision.
What a year of TRT monitoring costs at home
| Plan | What you get | Per year, with shipping |
|---|---|---|
| Hormone Focus + CBC, quarterly | T, SHBG, estradiol, PSA and hematocrit every test | $776 |
| Alternate Hormone Focus and Longevity, quarterly | T every test; PSA and estradiol twice; hematocrit, HbA1c and ApoB twice | $596 |
| Ultimate 360, twice a year | Everything, including hematocrit, PSA, iron and lipids | $548 |
| Hormone Focus + CBC, twice a year | The guideline core once stable | $388 |
Our arithmetic from SiPhox prices checked 29 Sep 2026: $124 per test, $25 shipping, CBC +$45, Ultimate 360 +$125. Check the CBC add-on is offered for your panel at checkout, and see our HSA and FSA guide for paying pre-tax. Many men on TRT compare SiPhox with Rythm Health; our SiPhox vs Rythm comparison covers that.
What an at-home test can and cannot do on TRT
- Measure testosterone, estradiol, PSA and hematocrit between clinic visits
- Keep draw timing consistent because you choose the day
- Show trends your prescriber can act on
- Diagnose anything or set a dose: a diagnosis and every dose change need a clinician
- Replace a venous CBC when hematocrit is near 54%
- Do a prostate exam or semen analysis
Best-fit SiPhox panel for TRT monitoring
| If you want | Test | Choose |
|---|---|---|
| The guideline core in one draw | Testosterone, SHBG, estradiol, PSA, plus hemoglobin and hematocrit | Hormone Focus + CBC add-on |
| Testosterone plus heart and blood markers | Total and free T, SHBG, hemoglobin, hematocrit, ApoB, HbA1c | Longevity Essentials |
| A yearly full check | All hormones, PSA, hematocrit, lipids, liver, kidney, iron | Ultimate 360 |
| A confirming venous CBC or PSA | Venous lab | Your prescriber |
Hormone Focus
Sex hormones for men and women, including PSA for men and progesterone for women.
Check price
Longevity Essentials
The default panel: heart, metabolic, hormone and inflammation markers in one draw.
Check price
Ultimate 360
Everything on the four core panels plus iron studies, B12 and folate, GGT and PSA.
Check price
Frequently asked questions
What blood work is needed for TRT?
Before starting: two morning total testosterone tests, LH, prolactin if LH is low or normal, hemoglobin and hematocrit, and PSA in men over 40. On treatment: testosterone and hematocrit at 3 to 6 months and yearly, and PSA at 3 to 12 months.
How often should blood be checked on TRT?
The Endocrine Society checks testosterone and hematocrit 3 to 6 months after starting, then yearly. The AUA measures testosterone every 6 to 12 months. Your prescriber may test more often after dose changes.
When should I get blood drawn on testosterone injections?
The Endocrine Society measures midway between injections. Some prescribers prefer a trough before the next dose. Keep the timing the same every test.
What hematocrit is too high on TRT?
The Endocrine Society says to stop testosterone if hematocrit rises above 54% until it falls to a safe level. Confirm a high capillary value with a venous CBC.
Do I need to check estradiol on TRT?
Neither guideline sets routine estradiol targets. The AUA recommends measuring it in men with breast symptoms or breast enlargement. Many prescribers check it anyway; interpret it with your prescriber.
Sources
- Bhasin S et al. Testosterone therapy in men with hypogonadism: an Endocrine Society clinical practice guideline. J Clin Endocrinol Metab 2018
- Endocrine Society: Testosterone therapy guideline, full text and recommendations
- American Urological Association: Evaluation and management of testosterone deficiency (2018, validity confirmed 2024)
- Travison TG et al. Harmonized reference ranges for circulating testosterone levels in men. J Clin Endocrinol Metab 2017
- MedlinePlus: Testosterone levels test
- MedlinePlus: Prostate-specific antigen (PSA) test
- MedlinePlus: Complete blood count (CBC)
- FDA: Biotin interference with lab tests
- SiPhox Health: Hormone Focus panel (checked 29 Sep 2026)
- SiPhox Health: Longevity Essentials panel and add-ons (checked 29 Sep 2026)
- SiPhox Health: Ultimate 360 panel (checked 29 Sep 2026)