Normal Is a Population, Not an Athlete: The Blood Panel, Line by Line

Every week someone asks what supplements I take. The answer is nothing. Nothing until blood work tells me what is missing. Ferritin and iron, B12, D3, then decide. I said it in this video: you could look great from the outside, so can a Ferrari, but the engine could be shit. Recovery is food. Recovery is sleep. Recovery is knowing what is going on inside you.

Testing changed two things. I stopped buying supplements on a hunch. I stopped blaming training for problems that were fuel. I know my resting metabolic rate and my expenditure and I eat to cover both. That is how 70 mile weeks became 100 to 120. That is how 8:15 pace at 154 beats became 8:09 at 129. Those numbers look like fitness. Fitness was not what changed. Food was. Underfueling is what I blame for most stress fractures and most stalled progress.

I am a coach, not a doctor. A blood panel is not a way to self-prescribe. It is a way to ask a physician better questions.

Getting the blood drawn is the easy part

Two routes. Your doctor is cheapest if you are insured, but you have to bring symptoms. Fatigue. Slipping paces at the same effort. Missed periods. A stress fracture. Then the request gets made directly. "I am a high-mileage runner. I want a CBC, ferritin, serum iron, TIBC, transferrin saturation, and 25-hydroxy vitamin D. Ferritin specifically, because hemoglobin can be normal while iron stores are empty." Route two is direct to consumer. Quest Health, Labcorp OnDemand, and Ulta Lab Tests all sell it. A network physician signs the requisition and you pick a draw site. Some states restrict it, and checkout will tell you.

Timing is the step people get wrong. Ferritin climbs with inflammation, peaking around 24 hours after hard exercise and staying up for 72. A draw two days after a long run turns a true ferritin of 25 into a 45. The deficient runner goes home happy. No hard session for 48 to 72 hours. 7 to 14 days clear of a race. Nothing within two weeks of illness. A fasted morning slot. 12 hours since the last iron pill. Same point in the training week every time.

The draw is nothing. A few tubes, ten minutes, results in one to five business days. I download every PDF. My own trend line is worth more than any single result. Once a year recreationally. Twice if you race ultras on 40-plus mile weeks. Every 8 to 12 weeks while correcting something. And 6 to 8 weeks before altitude.

Normal is a population, not an athlete

Reference ranges are descriptive, not prescriptive. They are the middle 95 percent of a mostly sedentary population, plenty of whom have marginal iron. Inside the range means unremarkable among non-athletes. It does not mean optimal at 100 miles a week.

That is why I test.

Ferritin is the highest-yield number a runner has. Under 15 is frank deficiency and a doctor visit. 15 to 20 is depleted and the lab still prints normal. 20 to 30 is functionally low at high volume, the quiet reason a block stops working. 40 to 90 is the band commonly cited for athletes. DellaValle and Haas screened one hundred sixty five collegiate rowers. Those under 20 ng/mL were about 21 seconds slower over 2,000 meters. Rowers at 30 and above showed no decrement. A meta-analysis of 17 trials found iron treatment improves iron status and aerobic capacity in deficient athletes who are not anemic.

Not anemic is the point. Ferritin falls first. Transport iron falls second. Hemoglobin falls last. The early stages are invisible on a CBC. Thirty percent of those rowers had low ferritin with normal hemoglobin. Runners drain it faster than anyone. Red cells rupture in the foot from footstrike hemolysis. Then hepcidin spikes about three hours after exercise and blocks the iron you just ate. Hard running causes gut bleeding. In women, heavy periods are the biggest driver of all.

If you are repleting, the biology matters. Absorption is best at breakfast after a morning run and drops 36 percent two hours post-exercise. Alternate days at 40 to 80 mg beats twice daily, with vitamin C, coffee and calcium an hour away. I would never start iron on a hunch. The lines also read together. Low ferritin plus transferrin saturation under 20 percent plus normal hemoglobin is the classic runner picture. A ferritin of 60 next to a CRP of 8 means the ferritin is inflated and unknown. hs-CRP belongs on the same order.

Vitamin D has four bands. Under 20 is deficient. 20 to 29 is insufficient. 30 and up is sufficient. 30 to 50 is the athlete band. Bone is why runners care. Female Navy recruits under 20 carried roughly double the stress fracture risk of recruits at 40 and above, and 74 percent of trainees with lower-leg stress fractures were under 30. February or March is when a draw shows your real floor. Correction is usually 2,000 to 5,000 IU a day, rechecked at three months.

B12 between 200 and 400 pg/mL is often symptomatic while reading normal, and if you are vegan that is your marker. Thyroid has two stories. High TSH with low free T4 is hypothyroidism. That needs a doctor. The other is free T3 falling while TSH stays in range, your metabolism turning down because you are not eating enough. That is REDs, and the fix is food.

CK I ignore unless something is wrong. The range is useless in runners, where values run 2 to 10 times the upper limit after normal work. The exception is real. CK in the thousands with dark urine, severe pain, or reduced urine output is possible rhabdomyolysis, and that is the emergency room today. Same for hemoglobin below range, ferritin under 15 or over 300, absent periods, or repeat stress fractures. Physician, not supplement store.

The version that costs nothing

If you will not pay anyone, the log is free. Heart rate at a fixed pace on a fixed route. Resting HR and HRV drifting across weeks. Cold hands, craving ice, hair shedding, and restless legs are classic low-iron tells. For women, menstrual regularity is the most informative free biomarker there is. Losing your cycle is a red flag by itself. Then three days of food logged against your training load, because most bad panels trace back to not eating enough.

Free blood work exists too. Employer wellness screenings often include a CBC and will add ferritin and vitamin D if you ask. Collegiate athletic departments run free iron screening, and the trainer knows. Donating blood is not a testing strategy. A donation costs you 200 to 250 mg of iron. I am careful with $40 to $120 fingerprick kits. Dried blood spot ferritin is one of the least reliable analytes, about 1 in 4 samples fail versus 1 in 33 for a venous draw. Venous ferritin is about $30.

What it costs and where to go

Cheapest is your doctor. $0 to $50 with a documented complaint, since ferritin is only about $16 on the Medicare fee schedule. On a high-deductible plan the hospital rate can run three to five times the cash price. Cash pricing is worth asking for. Next cheapest is assembling it yourself. CBC with differential, ferritin, iron with TIBC and saturation, 25-hydroxy vitamin D, and hs-CRP runs $110 to $150. Ferritin alone is $25 to $59. The same assay is worth comparing at FindLabTest first. Prices vary two to three times across resellers. HSA and FSA eligible.

Platforms sell the interpretation layer. WHOOP Advanced Labs is $199 to $599 a year. Function Health is $365 to $499. InsideTracker is a $149 membership plus $340 a panel. The extra money buys interpretation and adherence. It does not buy better data.

Booking one this week takes a ZIP code. Quest and Labcorp will show which network has a closer draw site. That storefront is where I buy. For a physician who already believes a ferritin of 22 matters in a runner, there is the AMSSM directory, and a sports dietitian at SportsRD. No lab nearby, Getlabs draws at your house for $35 to $99. The free step with the highest yield is asking your run club who takes runner iron seriously. The KEEP test finder at /testing puts the blood panel next to sweat, lactate, and metabolic testing.

And that brings me back to where this started. Every week someone asks what supplements I take. The answer is nothing. Nothing until blood work tells me what is missing. But more than that, the panel gave me a way to stop guessing. Patience, honesty, and evidence changed my training, not a shelf of bottles. I book the draw, then I go eat.