A practical checklist to get clean, comparable labs
Pre-Injection Bloodwork Checklist
If you test at random times, your results will lie to you. This checklist standardises timing and markers so you can compare labs across months and make changes based on real signals—not noise.
Want the full pathway? Go back to the Bloodwork category overview (start → interpret markers → monitor trends).
Why “pre-injection” bloodwork matters
“Pre-injection” (often called trough) bloodwork is the most repeatable reference point for people on injections. If you always test the same way, you can actually tell whether changes are helping.
If timing changes, you cannot compare results. Standardise first, then interpret. If you’re planning a schedule change, model it first with the TRT dose calculator so your “before vs after” is clean.
The checklist (do this before your blood draw)
1) Lock your protocol for long enough
- No protocol changes for 6–8 weeks before testing (dose, frequency, ester, injection route).
- Keep training, sleep, and alcohol reasonably consistent the week prior.
2) Pick the correct timing window
- Injection day? Test before your injection (same morning is ideal).
- Every N days schedule? Test on the morning your next dose is due (true trough).
- Daily micro-dosing? Test at your normal dose time, before dosing.
3) Control the obvious confounders (24–48 hours)
- Avoid an extreme leg session the day before (can affect inflammation markers and how you “feel”).
- Hydrate normally (dehydration can inflate hematocrit).
- Fast if you’re doing a lipid panel or glucose markers (follow your lab instructions).
4) Decide “what you’re trying to answer”
- Stability: “Is my baseline safe and steady?”
- Symptoms: “Do labs match what I feel?”
- Change planning: “If I change X, what baseline am I starting from?”
What to test (minimum viable panel)
These cover safety, hormone balance, and the most common drift points.
Hormones
- Total Testosterone (TT)
- Free Testosterone (FT) — if you have TT + SHBG (and albumin), you can estimate FT using the free testosterone calculator.
- SHBG
- Estradiol (E2, sensitive)
Safety & health
- CBC (hematocrit/hemoglobin/RBC)
- CMP (liver/kidney markers, electrolytes)
- Lipid Panel
Situational add-ons (use when relevant)
- Prolactin (libido/ED issues, nipple sensitivity, weird mood swings)
- TSH + Free T4 (± Free T3) (fatigue, cold intolerance, unexplained weight changes)
- PSA (age/risk factors—use your clinician’s guidance)
- HbA1c (metabolic health, weight/fat gain concerns)
After the draw, use How to read common lab markers to interpret the panel in context.
How to use results (without doing dumb stuff)
- Compare to your last trough test, not random “best day” results.
- Track trends (2–3 data points) before big decisions.
- Don’t chase a single number—symptoms + safety markers matter.
- Make one change at a time so you know what caused what.
Changing dose because E2 “looks high” without controlling timing is how people create chaos. If you’re about to change dose or frequency, do the order properly: checklist → draw → interpret → plan. Then use the TRT dose calculator to map the new schedule before you implement it.
Common questions
Should I test at trough or peak?
For repeatable monitoring, trough is the default. Peaks can be useful for specific questions, but trough is what lets you compare one set of labs to the next without guessing.
What if I missed a dose or injected late?
Don’t test. Fix the schedule, run 1–2 consistent weeks, then test properly. Garbage timing = garbage data.
Do I need fasting labs?
If you’re ordering lipids or glucose markers, yes—follow your lab’s fasting instructions. If it’s hormones only, fasting is less critical than consistent timing.
Where does this fit in the bigger flow?
If you’re brand new, read What is TRT? before you start changing anything. If you’re using tools, this checklist should be linked from the “before you calculate” area in the TRT calculator guide.
Key takeaways
- Test before your next injection (true trough) for comparability.
- Hold protocol steady for 6–8 weeks before testing.
- Order a focused panel that covers hormones + safety markers.
- Use trends, not single results, to guide changes.
Read How to read common lab markers, then set your monitoring cadence with Ongoing monitoring & follow-up labs.