Across the blood work we see from athletes and AAS users, patterns show up again and again — not in the marker values themselves, but in how the panels were collected. The same handful of mistakes show up repeatedly, quietly undermining the value of what would otherwise be actionable data.
Six blood work mistakes show up more often than anything else we see in practice. They're ranked below by how much they distort your results.
1. Training Before the Draw
This is by far the most frequent and impactful mistake. Training within 48 to 72 hours of a blood draw causes measurable elevations in creatinine, AST, and CK. These markers leak from exercised muscle tissue into the bloodstream, creating a picture that looks like kidney stress or liver damage, when in reality, you simply trained too close to the draw.
CK clears from circulation slowly, so a single rest day is not enough. A heavy leg day can push CK well above 2,000 U/L, and values that high can take five to seven days to fully normalize. Even light cardio can bump AST and creatinine slightly. If you are on orals, liver enzymes will be elevated anyway, so you need a clean baseline to separate drug effects from training effects. The practical rule: schedule your draw for a Monday morning after a completely sedentary weekend. If you cannot skip training, at least avoid lower body work and high volume for 72 hours. A short walk is fine, but anything that leaves you sore will skew the panel.
This is a recurring pattern, not an edge case: a user with perfectly healthy kidneys shows up with creatinine at 1.3 to 1.5 mg/dL and AST at 60 to 80 U/L, and a standard reading flags both as abnormal. The result: unnecessary worry, unnecessary follow-up testing, and sometimes even unnecessary medication changes.
The Fix
2. Incomplete Panels
A standard comprehensive metabolic panel (CMP) plus lipid panel leaves out three markers that are critical for AAS users.
ApoB is a direct count of atherogenic particles, while LDL is often calculated, not measured. When triglycerides are above 200 mg/dL, the Friedewald equation becomes unreliable and LDL can be underestimated by 20% or more. Cystatin C is not affected by muscle mass, but it is also more sensitive to early declines in GFR, which makes it ideal for athletes. GGT is induced by alcohol and oral AAS, so it helps you see if your liver is stressed by compounds rather than training. These three markers cost about $40 to $80 total and can be added to any standard panel without a licensed medical professional's order in most countries.
- ApoB: the single best predictor of cardiovascular risk, and almost never included in standard lipid panels.
- Cystatin C: the only kidney marker unaffected by muscle mass. eGFR from creatinine systematically underestimates kidney function in athletes.
- GGT: the only liver enzyme that does not rise from muscle damage. When AST and ALT are elevated but GGT is normal, the source is likely muscle, not the liver.
Without these three markers, you're flying blind on cardiovascular risk, kidney function, and liver origin assessment. They cost around $40 to $80 total and provide more actionable information than the entire standard panel combined.
You can order these tests directly from private labs. In the US, LabCorp and Quest run ApoB for about $30, Cystatin C for $40, and GGT for $15. In Europe, services like Medichecks and Blutwerte offer them as add-ons. If you are on a budget, prioritize ApoB and GGT. Cystatin C is most useful if you have high muscle mass or a history of kidney issues. Do not skip ApoB because your standard lipid panel shows normal LDL. Many users with LDL under 100 still have elevated ApoB, and that is the number that predicts cardiovascular events.
3. Testing at the Wrong Time
Timing errors come in two categories, and both are common.
Not fasting. A non-fasted lipid panel is essentially useless. Triglycerides can spike sharply after a meal, LDL calculations become unreliable, and glucose readings say nothing about metabolic health. A tell-tale sign in a report is implausibly high triglycerides paired with an otherwise unremarkable LDL — a pattern that shows up often enough to be worth checking for before trusting a lipid panel.
If you accidentally eat before a draw, do not cancel the whole panel. CBC, hormones, and most enzymes are not affected by food. Only lipids and glucose are. If you ate, reschedule the lipid test for another day, but you can still run the rest. Some labs accept a six hour fast, but eight to twelve is ideal. The key is consistency: always test fasted, first thing in the morning, with the same hydration status. If you are on a protocol that requires trough levels, like testosterone injections, also keep the injection schedule consistent. A non-fasted lipid panel is not just slightly off, it is useless for decision making.
Mid-cycle vs. post-cycle confusion. Users often test mid-cycle and then worry about lipid values that are expected to be suppressed. Low HDL and elevated LDL on 500 mg testosterone per week are pharmacological effects, not emergency signals. Conversely, testing post-cycle without waiting 6-8 weeks for recovery gives a misleading picture of your natural baseline.
When to Test
4. Not Establishing a Baseline
A single blood draw tells you where you are, not where you are going. Without a pre-cycle baseline, you cannot distinguish between:
- A marker that was always outside the standard range for you, and some people naturally run creatinine at 1.2.
- That marker shifted because of your cycle, plain and simple. When you're running compounds, your bloodwork reflects exactly what you put in, and this one is no exception. It moved off your baseline, and that's the direct result of what you're taking.
- A marker that drifted over time independent of compound use is a classic trap. You see a value shift on the lab report and your first instinct is to blame the gear, but the reality is that some biomarkers just wander on their own. They respond to stress, sleep, training load, or plain old biological noise, and none of that has anything to do with what you pinned that week. When you spot a change like that, you have to ask whether the compound actually caused it or whether the marker was already moving before you touched anything.
A large share of new users submit their first panel already on cycle, with no baseline to compare against. This is understandable: most people discover GearCheck after they've already started. But if you're planning your first cycle, the single most valuable blood draw is the one you take before you pin anything.
If you are already on cycle, you can still get useful information. Compare your current values to the reference ranges, but also look at trends over time. If you have any previous panels, even from before you started, you can see how your markers respond. For your next cycle, take a baseline four to six weeks before you start, and a post-cycle panel eight weeks after your last dose. That gives you three data points: baseline, on-cycle, and recovery. Without a baseline, a creatinine of 1.3 might be normal for you, or it might be a sign of kidney stress. The only way to know is to have a reference point.
5. Comparing Against Standard Ranges
This is not a mistake you make, but a mistake the lab makes for you. Standard reference ranges are calibrated on the general population: sedentary individuals, mixed ages, mixed health statuses. They are not designed for strength athletes.
Every lab in the country flags a creatinine of 1.3 mg/dL as high, but for a 200-pound lifter with 170 pounds of lean mass, that's perfectly normal. An AST of 55 U/L gets a red flag, yet for someone who trains five days a week, it's expected.
Athletic-adjusted ranges aren't printed on a standard lab report, but the pattern is well documented in sports and exercise medicine: creatinine, AST, and ALT all run measurably higher in trained, muscular individuals than in the sedentary reference population without that reflecting disease. The key is to look at trends: if your creatinine goes from 1.0 to 1.3 over a cycle, that is a change worth investigating, even if 1.3 is within the athletic range. Also, always check eGFR with cystatin C if you have high muscle mass. The standard eGFR formula will flag you as having stage 2 kidney disease when your kidneys are perfectly fine.
Lab flags are a distraction, plain and simple. They're calibrated for the general population, not for someone running supraphysiological doses or training like a professional. What you need to do instead is compare yourself against athletic reference ranges, and more importantly, against your own personal baseline. That baseline is the only number that actually tells you what's happening in your body. Track it over time, watch the trends, and let those guide your decisions.
6. Ignoring Blood Pressure
Blood work misses plenty. Blood pressure is arguably the single most important health metric for AAS users, and it never shows up on any lab requisition form.
Users will obsess over a slightly elevated LDL, yet their blood pressure sits at 140/90 and goes unaddressed. High blood pressure does more cardiovascular damage than any lipid value, and it's fully within your control. A home cuff costs 30 euros and takes 30 seconds per day.
Between blood draws, if you track nothing else, track your blood pressure. It's more responsive to interventions than almost any lab value, easier to measure, and more predictive of outcomes than nearly any laboratory marker.