Blood Testing Guide
Why Blood Tests Are Essential
Blood tests are the single most important harm reduction practice for DIY HRT. Without them, you are dosing blind - you have no way of knowing whether your levels are in range, too low (wasting money and getting no results), or too high (increasing health risks).
| Benefit | Why It Matters |
|---|---|
| Confirm your dose works | Are your levels in target range? |
| Detect problems early | Liver strain, high haematocrit, high prolactin - all treatable if caught early. |
| Adjust with evidence | Changes should be based on data, not guesses. |
| Peace of mind | Knowing your levels reduces anxiety about DIY. |
What to Test
Baseline (Before Starting HRT)
| Test | What It Shows |
|---|---|
| Estradiol (E2) | Baseline oestrogen level |
| Testosterone (total and free) | Baseline T level |
| LH, FSH | HPG axis function (pituitary response) |
| SHBG | Hormone-binding protein |
| CBC (complete blood count) | Red/white blood cells, platelets |
| Comprehensive metabolic panel | Liver function (ALT, AST), kidney function (creatinine), electrolytes |
| Lipid panel | Cholesterol, triglycerides |
| Prolactin | Baseline (especially important if using CPA) |
On HRT — First Year (Every 3 Months)
| Test | Target (Trans Feminine) | Target (Trans Masculine) |
|---|---|---|
| E2 | 100–200 pg/mL (367–734 pmol/L) | < 50 pg/mL (< 184 pmol/L) |
| Total T | < 50 ng/dL (< 1.73 nmol/L) | 300–1,000 ng/dL (10.4–34.7 nmol/L) |
| Free T | — | Mid-to-upper normal range |
| SHBG | 40–120 nmol/L (> 150 nmol/L signals excess binding) | 10–50 nmol/L |
| CBC | Normal | HCT < 54% |
| CMP | Normal | Normal |
| Prolactin | < 25 ng/mL (< 530 mIU/L) | N/A |
| Lipid panel | Monitor changes | Monitor changes |
After Stabilisation (Every 6–12 Months)
Same panel as above, plus any additional markers your specific regimen requires (e.g. prolactin for CPA users, haematocrit for T users).
Tips for Accurate Results
TEST AT TROUGH — NOT PEAK
For injectable hormones, blood must be drawn immediately before your next dose (trough).
- Estradiol injections: trough = just before next injection (e.g., day 5 or 7)
- Testosterone injections: trough = just before next injection (typically day 7)
Do not test within 48 hours of an injection. Testing at peak gives misleadingly high results and can cause you to lower your dose incorrectly.
| Tip | Detail |
|---|---|
| Test at trough for injectable E2 | For injections, test just before your next injection (lowest point). Optionally test at peak (24–48 h post-injection for EV; 3–5 days post-injection for EC/EEn) to confirm your E2 is not supraphysiologic (> 400 pg/mL / 1,470 pmol/L). |
| Test at trough | The lowest point in your dosing cycle - just before your next dose for injections, first thing in the morning for transdermal/oral. |
| Use the same lab | Different labs use different assays; consistency gives you comparable results over time. |
| Avoid biotin | Stop biotin-containing supplements 3–5 days before testing - it skews immunoassay results (LC-MS/MS is not affected by biotin, so if your lab uses LC-MS/MS this precaution is unnecessary). |
| Be consistent with timing | Always test at the same point in your cycle for meaningful comparisons. |
| Stay hydrated | Dehydration can concentrate blood and skew results. |
| Don't rush | If you change dose, wait 4–6 weeks before testing to reach steady state. |
Where to Get Blood Tests
Blood tests can be accessed through public healthcare systems (free or low-cost, but may require a GP referral), private lab services (pay directly, no referral needed), and direct-to-consumer companies (online ordering, home finger-prick or clinic visit). Below is a country-by-country breakdown of all options.
🇬🇧 United Kingdom
| Provider | Type | Cost | Prescription Needed? | Notes |
|---|---|---|---|---|
| NHS GP | Public | Free | Yes (GP referral) | You can request blood tests from your GP. You do not have to disclose DIY HRT - you can say you are under private care or investigating symptoms. Some trans-friendly GPs will test without judgement. |
| Medichecks | Private (online) | £39–£129 | No | Finger-prick or venous at a clinic. Wide range of HRT-specific panels (e.g. "Female Hormone Blood Test", "Male Hormone Blood Test"). Results reviewed by a doctor. |
| Randox Health | Private (online) | £39–£150 | No | Venous blood tests at Randox clinics across the UK. Offers "Advanced Hormone Check" covering E2, T, LH, FSH, SHBG, prolactin. |
| Thriva | Private (online) | £29–£129 | No | Finger-prick home test kits. Convenient but limited volume - cannot test everything from one finger-prick. Good for routine monitoring. |
| Forth | Private (online) | £59–£199 | No | Venous or finger-prick. Wide range of biomarkers including hormones, thyroid, lipids. Results reviewed by a nurse. |
| Blue Horizon Medicals | Private (online) | £29–£99 | No | Offers steroid and hormone panels popular in the fitness community. Full hormone profiles including E2 sensitive. |
| London Transgender Clinic | Private (clinic) | £150–£300 | No | Trans-specific private clinic. Provides blood testing as part of HRT monitoring. Can provide a letter for NHS shared care. |
| GenderGP | Private (online) | £50–£150 | No | Online gender service. Offers blood test kits and result interpretation for DIY patients. |
| Local sexual health / GUM clinics | Public | Free | No (walk-in) | Some clinics will test hormone levels when you explain your situation. Results may take longer. |
🇺🇸 United States
| Provider | Type | Cost | Prescription Needed? | Notes |
|---|---|---|---|---|
| Medicare / Medicaid | Public | Free/low | Yes (doctor referral) | If you have public insurance, your PCP can order blood tests. Cost is covered or minimal. |
| Planned Parenthood | Public/Non-profit | $0–$200 (sliding scale) | No (informed consent) | Many locations provide trans healthcare including blood test monitoring. Sliding scale fees available. |
| Private MD Labs | Private (online) | $50–$150 | No | Order online, get tested at LabCorp. Wide range of panels. Popular in the trans community. Use code for discounts. |
| Jason Health | Private (online) | $40–$120 | No | Order online, get tested at Quest Diagnostics. Cheapest option for basic hormone panels. |
| Walk-In Lab | Private (online) | $55–$170 | No | Order online, choose LabCorp or Quest. Good customer service and panel descriptions. |
| Ulta Lab Tests | Private (online) | $60–$200 | No | Order online, test at LabCorp or Quest. Often has sales and coupon codes. |
| Health Testing Centers | Private (online) | $50–$180 | No | Order online, test at LabCorp or Quest. Simple ordering process. |
| Any Lab Test Now | Private (walk-in) | $50–$200 | No | Franchise with physical locations. Walk in, order a panel, get tested on the spot. Results in 1–3 days. |
| LabCorp (direct) | Private (walk-in) | Varies | No | Some LabCorp locations allow direct ordering without a doctor - call ahead to confirm. |
| Quest Diagnostics (direct) | Private (walk-in) | Varies | No | Similar to LabCorp - some locations accept self-referred patients. |
| Local community health centres | Public/Non-profit | Sliding scale | Varies | Many LGBTQ+ health centres offer blood testing as part of trans healthcare services. |
Note on US prices: Prices shown are for self-pay without insurance. If you have insurance, using a doctor's referral will be much cheaper (copay only). The online services above are primarily for people without insurance or who cannot get a doctor's referral.
🇨🇦 Canada
| Provider | Type | Cost | Prescription Needed? | Notes |
|---|---|---|---|---|
| Provincial health (MSP, OHIP, etc.) | Public | Free | Yes (doctor referral) | Each province has its own health insurance plan. A GP or walk-in clinic can requisition blood tests at provincial labs (Lifelabs, Dynacare). Free if covered. |
| Lifelabs | Private (direct) | $50–$200 | No (in some provinces) | Lifelabs allows self-referred blood tests in BC and Ontario for certain panels. Call to confirm. |
| Dynacare | Private (direct) | $50–$200 | No (in some provinces) | Similar to Lifelabs - self-referred testing available in Ontario and other provinces. |
| Walk-In Lab (Canada) | Private (online) | $60–$180 | No | Order online, test at Lifelabs or Dynacare. Canadian-specific panels available. |
| Any Lab Test Now (Canada) | Private (walk-in) | $60–$200 | No | Walk-in locations in some Canadian cities. No appointment or prescription needed. |
| Blood Test Canada | Private (online) | $55–$170 | No | Online service with Canadian lab partners. Hormone panels available. |
| Local sexual health / trans clinics | Public/Non-profit | Free–$50 | Varies | Many cities have trans-specific clinics that can order blood tests (e.g., Sherbourne Health in Toronto, Three Bridges in Vancouver). |
| UBC AMS Peer Support | Free | Free | No | Offers free injection kits and can help connect students with blood testing resources. |
Note: In Canada, the most cost-effective path is usually to get a GP or walk-in clinic to requisition blood tests through the provincial system. If you do not have a doctor, telehealth services (e.g., Maple, Tia Health) can provide referrals.
🇦🇺 Australia
| Provider | Type | Cost | Prescription Needed? | Notes |
|---|---|---|---|---|
| Medicare (GP referral) | Public | Free (bulk billed) or $50–$100 (private GP) | Yes (GP referral) | See a GP, ask for blood tests. If they bulk bill, the test and visit are free. Some GPs are trans-friendly; search the TransHub provider directory. |
| Clinical Labs (direct access) | Private (direct) | $60–$200 | No | Some Clinical Labs locations accept self-referred patients without a doctor's form. Call ahead. |
| Laverty Pathology / Healius (direct access) | Private (direct) | $60–$200 | No | Some collection centres allow self-referred testing. Check with your local branch. |
| Australian Clinical Labs (direct access) | Private (direct) | $60–$200 | No | Similar to above - some locations accept walk-in self-referrals. |
| iMedical | Private (online) | $40–$120 | No | Online ordering for blood tests. Limited test menu compared to US/UK services. |
| Private Pathology (direct booking) | Private (walk-in) | $80–$250 | No | You can book directly with some private pathology providers without a referral - expect to pay full price. |
| Family Planning Clinics | Public/Non-profit | Free–$50 | No | Some family planning clinics (e.g., Family Planning NSW) provide trans healthcare including blood test referrals. |
| Local sexual health clinics | Public | Free | No (walk-in) | Free or low-cost STI and hormone testing available at sexual health clinics. Results within a week. |
| TransHub / ACON | Non-profit | Free | No | NSW-based trans health resources. Can help connect you with trans-friendly GPs and blood testing services. |
Note: Testosterone is a controlled substance in Australia. If you are on T, be cautious about disclosing DIY status to GPs. Oestrogen faces fewer restrictions.
🇪🇺 Europe
🇩🇪 Germany
| Provider | Type | Cost | Prescription Needed? | Notes |
|---|---|---|---|---|
| Gesetzliche Krankenkasse (public insurance) | Public | Free (covered) | Yes (doctor referral) | If you have public insurance, a doctor can order blood tests. Free or minimal copay. |
| Die Laborärzte | Private (direct) | €30–€100 | No | Direct-to-consumer lab testing. Wide range of hormone panels available without a prescription. |
| GanzImmun | Private (online) | €40–€150 | No | Online blood test ordering with clinic visits across Germany. Hormone panels including E2, T, LH, FSH. |
| Medlanes | Private (online) | €35–€120 | No | Online lab service. Choose your panel, visit a participating clinic for blood draw. |
| Berlin-Chemie / Synlab | Private (direct) | €40–€150 | No | Large lab network. Some locations accept self-referred patients. |
| Local trans counselling centres | Non-profit | Free–€20 | No | Many German cities have trans counselling centres (e.g., Berliner CSD, TransInterBeratung) that can connect you with trans-friendly doctors. |
🇫🇷 France
| Provider | Type | Cost | Prescription Needed? | Notes |
|---|---|---|---|---|
| Sécurité Sociale (public insurance) | Public | Free (covered) | Yes (doctor referral) | Public insurance covers blood tests with a doctor's order. Copay may apply. |
| Cerba | Private (direct) | €30–€120 | No | Large French lab network. Some locations accept self-referred patients without a prescription. |
| Biomnis | Private (direct) | €30–€120 | No | Similar to Cerba. Direct access testing available at some locations. |
| Labos du drive / drive labs | Private (direct) | €25–€80 | No | Participating labs that accept self-referred walk-ins. Check their website for participating locations. |
| France Assos Santé | Non-profit | Free | No | Can help you find trans-friendly providers in the healthcare system and find trans-friendly providers. |
🇳🇱 Netherlands
| Provider | Type | Cost | Prescription Needed? | Notes |
|---|---|---|---|---|
| Zorgverzekering (public insurance) | Public | Free (covered, own risk applies) | Yes (GP referral) | GP can refer you to a lab. Covered by insurance after the deductible (€385 eigen risico in 2025). |
| Bloedwaardentest.nl | Private (online) | €35–€130 | No | Online blood test ordering. Home finger-prick or visit a participating lab. Hormone panels available. |
| Labplus | Private (online) | €40–€150 | No | Online ordering for lab visits. Wide range of biomarkers. |
| GenderGP | Private (online) | £50–£150 | No | UK-based but serves EU patients. Provides blood test referrals and result interpretation. |
| Local trans health clinics | Public/Private | Varies | Varies | Gender clinics (e.g., PsyTrans, Stepwork) can order blood tests as part of care. |
🇪🇸 Spain
| Provider | Type | Cost | Prescription Needed? | Notes |
|---|---|---|---|---|
| Seguridad Social (public) | Public | Free | Yes (doctor referral) | Public system covers blood tests with a doctor's order. |
| Synlab Spain | Private (direct) | €30–€120 | No | Large lab network with direct access testing at many locations. |
| Analiza.es | Private (online) | €30–€90 | No | Online platform for booking blood tests without a prescription. |
| Local trans associations | Non-profit | Free | No | Groups like Fundación Triángulo, Chrysallis, or local LGBT centres can help connect you with trans-friendly healthcare. |
🇮🇹 Italy
| Provider | Type | Cost | Prescription Needed? | Notes |
|---|---|---|---|---|
| Servizio Sanitario Nazionale (public) | Public | Free (ticket may apply) | Yes (doctor referral) | Public system covers blood tests with a doctor's prescription (ricetta). |
| Lifebrain | Private (direct) | €30–€100 | No | Private lab network. Direct access testing available without a prescription. |
| Biontech / Biotekna | Private (direct) | €30–€100 | No | Some private labs accept self-referred patients. Call ahead. |
| Local trans clinics | Public/Private | Varies | Varies | Some hospitals have gender clinics (e.g., Careggi in Florence, San Camillo in Rome) that can order blood tests. |
General note on Europe: In most EU countries, the cheapest option is through public healthcare with a doctor's referral. If you cannot get a referral, the private online services listed above work across multiple EU countries. Let's Get Checked also ships to many EU countries.
🇮🇳 India
| Provider | Type | Cost | Prescription Needed? | Notes |
|---|---|---|---|---|
| Government hospitals | Public | Free–₹500 | Yes (doctor referral) | Public hospitals offer blood tests at very low cost. Wait times can be long. |
| Thyrocare | Private (direct) | ₹500–₹2,000 | No | Large pan-Indian lab network. Offers "Health Check" and "Wellness" packages including hormone panels (T3, T4, TSH, E2, T, LH, FSH). Home collection available. |
| Dr. Lal PathLabs | Private (direct) | ₹600–₹3,000 | No | Wide network across India. Direct walk-in or home collection. Hormone-specific packages available. |
| SRL Diagnostics | Private (direct) | ₹500–₹2,500 | No | Pan-Indian lab. Self-referred testing accepted. Offers "Hormone Profile" packages. |
| Metropolis Healthcare | Private (direct) | ₹600–₹3,000 | No | Large lab chain with home collection. Full hormone panels. |
| 1mg | Private (online) | ₹400–₹2,000 | No | Online booking platform. Schedule home collection or visit a lab. Wide range of tests. |
| PharmEasy | Private (online) | ₹400–₹2,000 | No | Similar to 1mg. Book blood tests online with home collection. |
| Practo | Private (online) | ₹500–₹2,500 | No | Online healthcare platform. Book blood tests from partner labs with home collection. |
| Apollo Diagnostics | Private (direct) | ₹500–₹2,500 | No | Part of the Apollo hospital network. Direct walk-in testing available. |
| Local pathology labs | Private (direct) | ₹300–₹1,000 | No | Most cities have small local pathology labs that do blood tests at very low cost without a prescription. Quality varies. |
Note on India: Blood testing in India is significantly cheaper than in Western countries. A full hormone panel (E2, T, LH, FSH, prolactin, SHBG, CBC, CMP) can cost as little as ₹1,500–₹3,000 ($18–$36 USD) through Thyrocare or Dr. Lal PathLabs. Home collection is widely available in major cities.
🌍 Global & Online Services (Ship Internationally)
| Provider | Headquarters | Ships To | Type | Cost (USD) | Prescription Needed? | Notes |
|---|---|---|---|---|---|---|
| Let's Get Checked | Ireland | Most countries (US, UK, EU, CA, AU, NZ) | Home finger-prick kit | $89–$249 | No | Well-known direct-to-consumer service. Hormone and health panels available. Results reviewed by a nurse. Ships internationally. |
| Forth | UK | UK, some EU | Home finger-prick or venous | £59–£199 | No | Offers "Ultimate Performance" and hormone panels. International shipping expanding. |
| Medichecks | UK | UK, some EU | Home finger-prick or venous | £39–£129 | No | Ships to some EU countries. Check their international delivery page. |
| Walk-In Lab | US | US, Canada (limited) | Lab visit (LabCorp/Quest) | $50–$170 | No | International customers can order and use affiliated labs if available in their region. |
| Private MD Labs | US | US (LabCorp) | Lab visit (LabCorp) | $50–$150 | No | US-only (LabCorp network). Requires travel to a LabCorp location. |
| iMedical | Australia | Australia | Lab visit (partner labs) | $40–$120 | No | Australia-only. Must visit a local partner lab. |
| GanzImmun | Germany | Germany, Austria, Switzerland | Lab visit | €40–€150 | No | EU-focused. Must visit a participating clinic. |
| Local private labs | Varies | Local | Lab visit | Varies | No | Search for "private blood test [country/city]" or "direct access lab [country]". Many countries have private lab networks that accept self-referred patients. |
Key Markers Explained
For Trans Feminine People
| Marker | Target | If Too Low | If Too High |
|---|---|---|---|
| E2 | 100–200 pg/mL (367–734 pmol/L) | Poor feminisation, low mood, hot flushes | Elevated VTE risk, mood changes, high SHBG (binding E2, reducing effectiveness) |
| Total T | < 50 ng/dL (< 1.73 nmol/L) | N/A — lower is the goal | Continued masculinisation, androgenic side effects |
| E1 (Estrone) | Not routinely needed | — | WPATH SOC8: E1:E2 ratio need not be measured; no evidence it impairs feminisation. Parenteral routes avoid high E1. |
| SHBG | 40–120 nmol/L | Below 40: free E2 may be higher than expected | > 150 nmol/L: binds too much E2 — paradoxically, reducing E2 dose may free up more bioavailable E2 |
| Prolactin | < 25 ng/mL (< 530 mIU/L) | Normal | CPA side effect; risk of prolactinoma if persistently > 100 ng/mL (> 2,120 mIU/L) |
| HCT | < 48% | Normal | Polycythaemia risk — rare on E alone |
For Trans Masculine People
| Marker | Target | If Too Low | If Too High |
|---|---|---|---|
| Total T | 300–1,000 ng/dL (10.4–34.7 nmol/L) | Poor masculinisation, fatigue, low libido | Polycythaemia, irritability, acne, scalp hair loss, high E2 (aromatisation) |
| Free T | Mid-to-upper normal range | Symptoms of low T despite normal total T | Androgenic side effects — check SHBG if disproportionate |
| E2 | < 50 pg/mL (< 184 pmol/L) | N/A | High T → aromatisation → possible oestrogenic effects (mood changes, water retention) |
| HCT | < 54% | Normal | Polycythaemia — donate blood if elevated; reduce T dose if persistent |
| SHBG | 10–50 nmol/L | May cause high free T symptoms | Lowers free T availability |
Understanding Your Results
E2 (Estradiol) - Trans Fem Special Considerations
| Scenario | Likely Cause | Action |
|---|---|---|
| E2 low despite moderate dose | Oral E2 has low bioavailability; high SHBG binding; dose too low | Increase dose or switch to parenteral route (sublingual, transdermal, injection) |
| E2 high despite moderate dose | Injectable E2 produces high peaks; sensitive to E2 | Reduce dose; check trough levels only |
| E2 low and SHBG high | Too much E2 causing SHBG to rise, which then binds E2 | Reduce E2 dose - paradoxically, less E2 can free up more bioavailable E2 |
| E1 much higher than E2 | Taking oral oestradiol - high first-pass conversion | Switch to sublingual/buccal, transdermal, or injectable if desired. Note: WPATH SOC8 states E1:E2 ratio need not be measured as recent evidence does not support it affecting outcomes. |
T (Testosterone) - Trans Masc Special Considerations
| Scenario | Likely Cause | Action |
|---|---|---|
| T low despite standard dose | Poor absorption (gel); wrong injection frequency | Switch to injections or increase gel dose; shorten injection interval |
| T high despite standard dose | Genetics; injecting too frequently for your ester | Reduce dose or lengthen injection interval |
| T peak too high, trough too low | Injection interval too long for your ester | Divide dose (e.g. once weekly -> twice weekly) |
| HCT rising | T stimulating erythropoiesis | Donate blood; if persistent, reduce T dose |
SHBG Explained
Sex hormone-binding globulin (SHBG) is a protein produced by the liver that binds to oestradiol and testosterone, making them unavailable to tissues. Only the unbound (free) fraction is biologically active.
SHBG: target vs. interpretation
The "On HRT" table above shows 40–120 nmol/L as the typical range for trans feminine people. This is a typical range, not a strict target — values slightly outside this range may still be fine depending on your overall picture. The interpretation table below gives clinical meaning to values below 40, within 40–120, and above 150 nmol/L.
How HRT Affects SHBG
| Regimen | Effect on SHBG | What It Means |
|---|---|---|
| Oral oestradiol | Raises SHBG significantly | High first-pass liver metabolism stimulates SHBG production |
| Injectable oestradiol | Raises SHBG moderately | Less liver impact than oral |
| Transdermal oestradiol | Raises SHBG minimally | Lowest liver impact |
| Testosterone therapy | Lowers SHBG | T suppresses SHBG production |
| CPA (cyproterone acetate) | May raise SHBG | Adds to oestrogen's effect |
Interpreting SHBG
| SHBG Level | What It Suggests |
|---|---|
| < 40 nmol/L (trans fem) | Low SHBG can mean free E2 is higher than expected for a given total E2. May cause androgenic symptoms if T is not fully suppressed. |
| 40-120 nmol/L (trans fem) | Normal range. Total E2 roughly reflects free E2. |
| > 150 nmol/L (trans fem) | High SHBG binds too much E2. You may need a higher total E2 to achieve adequate free E2. Paradoxically, reducing the E2 dose can lower SHBG and free up more bioavailable E2. |
| < 10 nmol/L (trans masc) | Low SHBG means free T is high relative to total T. Can cause androgenic side effects even if total T is in range. |
| 10-50 nmol/L (trans masc) | Normal range. |
| > 50 nmol/L (trans masc) | Uncommon on T therapy (T lowers SHBG). May indicate thyroid issue or other condition. |
Assay Types: LC-MS/MS vs Immunoassay
Not all lab tests are equally accurate. The type of assay used matters, especially at low or high hormone concentrations.
| Assay Type | How It Works | Accuracy | Best For |
|---|---|---|---|
| LC-MS/MS (liquid chromatography-tandem mass spectrometry) | Separates molecules by mass and charge | Gold standard - highly accurate at all levels | Low E2 (< 50 pg/mL), low T (< 50 ng/dL), free T by equilibrium dialysis |
| Immunoassay (CLIA, ECLIA, RIA) | Uses antibodies to detect hormones | Less accurate at extremes; can overestimate at low levels | Routine monitoring at moderate-to-high levels; cheaper |
Which Assay Should You Get?
- Trans women: If you are testing E2, immunoassay is usually fine above 50 pg/mL. For T suppression (< 50 ng/dL), LC-MS/MS is more reliable - immunoassay can overestimate low T.
- Trans men: For total T, immunoassay is usually adequate in the 300-1000 ng/dL range. For free T, ask for equilibrium dialysis (the most accurate method).
- If your levels do not match your symptoms: Consider retesting with LC-MS/MS. Immunoassay errors are a common cause of confusing results.
Checking Your Lab Report
Look at your lab report for method notation. LC-MS/MS is often labelled as "LC/MS/MS", "Mass Spectrometry", or "Tandem Mass Spec". Immunoassay may be labelled as "ECLIA", "CLIA", "Chemiluminescent", or simply "Immunoassay".
Free vs Bound Hormones
Standard blood tests measure total hormone levels (bound + free). But only the free fraction is biologically active.
| Marker | What It Measures | When to Check |
|---|---|---|
| Total T | All testosterone (bound to SHBG + bound to albumin + free) | Standard monitoring |
| Free T | Testosterone not bound to any protein | If total T seems inconsistent with symptoms (e.g. low T symptoms despite normal total T) |
| Free T by equilibrium dialysis | Gold standard for free T | Most accurate method |
| Free androgen index (FAI) | Calculated from total T and SHBG | Rough estimate only - less accurate than direct measurement |
| Bioavailable T | Free T + albumin-bound T (albumin binding is weak, so this T is still active) | Sometimes calculated instead of free T |
Rule of thumb: If your SHBG is within the normal range, total hormone levels are a reasonable guide. If SHBG is high or low, free hormone levels give a truer picture.
Prolactin Management
Prolactin is a pituitary hormone that can rise on oestrogen therapy, especially when combined with cyproterone acetate (CPA).
Prolactin Levels and Action
| Level | Risk | Action |
|---|---|---|
| < 25 ng/mL (< 530 mIU/L) | Normal | No action needed |
| 25–50 ng/mL (530–1,060 mIU/L) | Mild elevation | Monitor. Common on E + CPA. Recheck in 3 months. |
| 50–100 ng/mL (1,060–2,120 mIU/L) | Moderate elevation | Consider reducing CPA dose or switching AA. Rule out other causes (stress, sleep, other meds). |
| > 100 ng/mL (> 2,120 mIU/L) | Significant elevation | Stop CPA. Switch to bicalutamide or monotherapy. Consider MRI to rule out prolactinoma. |
| > 200 ng/mL (> 4,240 mIU/L) | High concern | Likely prolactinoma. Needs endocrinology workup and MRI. |
Reducing Prolactin
- Reduce or stop CPA - The most common cause in trans women. CPA at 12.5 mg/day or less is safer than 25-50 mg/day.
- Switch to bicalutamide - Bicalutamide does not raise prolactin.
- Switch to oestrogen monotherapy - High enough E2 levels suppress T without an AA.
- Check for other causes - Stress, sleep deprivation, chest wall stimulation, hypothyroidism, and certain medications (antipsychotics, antidepressants) can all raise prolactin.
Home Finger-Prick vs Venous Blood Draw
Many direct-to-consumer services offer home finger-prick kits. These are convenient but have limitations compared to venous blood draw.
| Aspect | Finger-Prick (Capillary) | Venous Draw |
|---|---|---|
| Sample volume | Very small (a few drops) | Larger (several mL) - can run many tests |
| Accuracy | Can be affected by squeezing, haemolysis, or contamination | More reliable, less prone to collection errors |
| Number of tests | Limited by volume | Can run a full panel from one draw |
| Convenience | High - do it at home, mail it in | Requires clinic visit |
| Cost | Usually lower | Usually higher |
| Turnaround | 3-7 days (includes shipping time) | 1-3 days |
Recommendation: Finger-prick tests are fine for routine monitoring of a few key markers (E2, T, SHBG) after you are stable. For your first test, a full panel, or if results seem off, use venous draw for accuracy.
Tracking Results Over Time
Keeping a log of your blood test results helps you spot trends and make informed dose decisions.
What to Track
| Field | Example |
|---|---|
| Date | 2026-04-15 |
| Days since last dose | 7 days (trough) |
| Current dose and route | 4 mg EV IM every 5 days |
| E2 | 147 pg/mL |
| Total T | 18 ng/dL |
| SHBG | 85 nmol/L |
| Prolactin | 12 ng/mL |
| HCT | 42% |
| Notes | Feeling good, no side effects |
Using a Spreadsheet or App
A simple spreadsheet (Google Sheets, Excel) or a notes app works well. Plotting E2 and T values over time on a chart makes it easy to see whether your levels are trending up, down, or stable. Many community members share template spreadsheets on r/TransDIY.
Troubleshooting Common Problems
| Problem | Solution |
|---|---|
| GP refuses to test | Switch to a private online service (Medichecks, Thriva, Private MD Labs). Some GPs respond better if you say you are "investigating symptoms" rather than monitoring DIY HRT. |
| Results seem wrong | Rule out lab error - retest at a different lab or at a different point in your cycle. Check if you took biotin recently. Consider assay type (immunoassay error is common at low T levels). |
| Can't get trough timing right | For injections, test immediately before your next shot. For gel, test in the morning before applying. For patches, test just before changing. |
| Cost is prohibitive | Check if your country has free sexual health clinics; use sliding-scale services; find community members who pool tests (buy one panel, share the cost). |
| Different labs give different results | Labs use different assays. Stick to one lab for consistency. If switching labs, do one test at both to calibrate. |
| Doctor says your levels are "normal" but they are not in target range | Many labs use cisgender reference ranges. Explain that you are on HRT and need transsexual-specific targets. Bring the WPATH or Endocrine Society targets. |
References
- UCSF Transgender Care. Guidelines for the Primary and Gender-Affirming Care of Transgender and Gender Nonbinary People. https://transcare.ucsf.edu/guidelines
- Hembree WC, et al. (2017). Endocrine Treatment of Gender-Dysphoric/Gender-Incongruent Persons: An Endocrine Society Clinical Practice Guideline. JCEM, 102(11):3869–3903. https://academic.oup.com/jcem/article/102/11/3869/4157558
- WPATH. Standards of Care, Version 8. International Journal of Transgender Health, 23(S1). https://www.tandfonline.com/doi/full/10.1080/26895269.2022.2100644
- TransHarmReduction. Blood Testing Guide. https://www.transharmreduction.org/