Markers · Reading your results
Every result flagged normal, and you still feel off. How to read your blood test results.
The portal says normal. Forty-one results, a column of them with nothing flagged, and a note from the office that reads “labs look good.” You're still dragging yourself through every afternoon, you're cold in rooms nobody else minds, and your cycle's moved by a week.
Both things can be true at once. A blood test result is a number read against a range, and a flag only tells you which side of that range it landed on. It doesn't tell you what the number means beside the other forty, whether it's moving, or whether it was drawn under conditions that change what it says.
Reading your own results well comes down to four questions, asked of every marker:
- Which range is it being read against?
- Which other markers check it?
- Which way has it been moving?
- What was going on when it was drawn?
Ask all four. One flag answers none of them.
Read it against two ranges, not one
The range printed beside your number is a reference range. A lab builds it from the middle 95% of the people it tests, so it describes who walked in the door, not what a body runs best on. When most of the people tested are tired, insulin resistant and short on iron, the range quietly makes room for all three.
A functional target is narrower. It's the band where the system the marker reports on tends to work well, read the way a functional and integrative medicine clinician would. Here's the gap for four markers people ask about most:
| Marker | Lab reference range | Functional target |
|---|---|---|
| TSH | 0.45-4.5 mIU/L | 1.0-3.0 mIU/L |
| Fasting insulin | 2-25 µIU/mL | 2-5 µIU/mL, with 10 as the ceiling |
| HbA1c | Under 5.7% | 4.6-5.3% |
| Homocysteine | 5-15 µmol/L | Under 12 µmol/L |
A fasting insulin of 14 µIU/mL clears the lab's range with room to spare and sits nearly three times the top of the target. That's the same number read two ways, and only one of them takes your 3 p.m. crash seriously.
The reference range is still the one a diagnosis is made against, and it should be. The functional target doesn't replace it; it tells you where inside “normal” you're standing.
Read every marker against both. Then read it beside the others.
Read each marker beside the ones that check it
No marker on a panel stands alone. Each one has a few others that confirm it, contradict it or explain it, and those are the ones to read it with.
Thyroid: TSH, free T4, free T3, TPO antibodies.
TSH is the pituitary's signal to the thyroid, so it reports how hard the brain is asking, not how much active hormone reaches your cells. A TSH of 2.8 looks settled until free T3 comes back at 2.4 pg/mL, under the 3.0-4.5 target, beside TPO antibodies at 30 IU/mL: inside the lab's under-35 cutoff, and well above the 0-6.8 target. That's an immune process working on the gland while the signal still reads calm. Biotin, the main ingredient in most hair, skin and nails formulas, can make TSH read low and free T4 and free T3 read high on some assays. When the numbers disagree with how you feel and your resting heart rate, stop the biotin and redraw. Read it all with the Thyroid & Adrenal guide.
Testosterone: total testosterone, SHBG, albumin, free testosterone.
Total testosterone counts all of it, and most of it rides bound to SHBG (sex hormone binding globulin) or albumin. The SHBG-bound share isn't available to tissue. A man's total of 540 ng/dL looks settled against the 500-900 target until SHBG comes back high and free testosterone comes back low. Measured free testosterone and the free testosterone calculated from total testosterone, SHBG and albumin should agree. When they don't, check the units first - pg/mL and ng/dL sit a factor of ten apart - and then the assay. Read it with the Low T guide.
Blood sugar: fasting insulin, fasting glucose, HbA1c, triglycerides.
Fasting insulin can climb for years while fasting glucose still looks normal, because the pancreas is working harder to hold glucose where it is. Read a glucose of 92 mg/dL beside an insulin of 14 µIU/mL and triglycerides of 160 mg/dL, and the panel is describing insulin resistance that glucose alone hides. HbA1c needs its own cross-check: it rides on how long red blood cells live, so anemia or recent blood loss can move it away from your real average. Read it beside a complete blood count and fructosamine, which tracks the last two to three weeks and doesn't depend on red cells. Then read the Metabolic Derailment guide.
Inflammation: hs-CRP, white cell count, and the calendar.
hs-CRP is made by the liver in response to inflammation anywhere in the body, so a high one says something is inflamed, not where or for how long. An hs-CRP of 4.2 mg/L the week after a cold is the immune system doing its job. The same 4.2 on three draws a year apart, against a target under 0.8, beside a white cell count that never moved, is a low-grade process that hasn't let up. Read the date, the white cell count and what you were recovering from, then read the Immune Resilience guide.
Methylation: homocysteine, vitamin B12, folate, MMA.
Homocysteine rises when the methylation pathways that clear it fall behind, often from low B vitamins. Serum B12 alone can miss a functional deficiency, which is why it's read beside homocysteine and methylmalonic acid (MMA). A B12 of 380 pg/mL is in range and below the 545-1100 target. Beside a homocysteine of 13 µmol/L, over the under-12 target, it's describing a shortfall the B12 number alone won't show.
Read the direction, not just the draw
One panel is a photograph. Three panels over three years are a film, and the film is where most of the story is.
A TSH of 1.9, then 2.6, then 3.4 never trips a flag. Each one is normal. The direction isn't: the pituitary is asking a little harder every year, and the fourth draw is the one that finally crosses 4.5. An hs-CRP that goes 0.6, 1.1, 1.9 mg/L is the same shape. So is an HbA1c that steps from 5.2% to 5.5% to 5.7%.
Three habits make a trend worth trusting:
- Pull every panel you have, from every office and every lab, back as far as they go. Old results are data, not clutter.
- Match the conditions. Same time of day, same fasting state, same lab where you can. A morning fasting draw and an afternoon one after lunch aren't measuring the same body.
- Ignore the wobble. Every marker moves a little from day to day on its own. A change smaller than that natural swing isn't a change, and two draws in the same direction carry more weight than one big jump.
If you're on a medication meant to move a marker and the number isn't where it's expected to be, bring both to your prescriber: the dose, how long you've been on it, and the trend.
Read it in the conditions it was drawn in
A number carries the day it was drawn on. Before you read one, write down what was going on, then check it against this:
| Before the draw | What it moves | What settles it |
|---|---|---|
| A meal, or a short fast | Triglycerides and insulin read higher | Redraw after an overnight fast |
| An afternoon draw | Total testosterone reads lower than its morning peak | Redraw before 10 a.m. |
| The day of your cycle | Estradiol and progesterone swing several-fold across a cycle | Note the cycle day; read progesterone about a week before your period |
| Breastfeeding | Estradiol sits low on purpose | Read it beside prolactin, LH, FSH and how often you're feeding |
| Creatine | Creatinine climbs, and kidney function looks worse than it is | Check cystatin C, SDMA, urine microalbumin and blood pressure |
| Biotin | Some thyroid and hormone tests read falsely high or low | Stop it and redraw |
| A hard workout in the last few days | Liver enzymes, CK and hs-CRP rise | Redraw after a few easier days |
| A cold, an infection or an injury | hs-CRP and white cell count rise | Redraw once you've recovered |
A creatinine of 1.3 mg/dL in someone taking creatine every day, beside a normal cystatin C, a clean urine microalbumin and a blood pressure of 118/76, isn't a kidney problem. The creatinine is reporting the creatine. The other three are reporting the kidneys.
What to do with yours
- Gather every panel you have, from every office and every lab.
- Write down what was going on before each draw.
- Read each marker against its lab range and its functional target.
- Read it beside the markers that check it.
- Line the draws up by date and read the direction.
- Bring what doesn't add up to your clinician, with the cross-checks you'd want run.
Educational context for your conversations with your licensed healthcare provider, not a diagnosis or a treatment plan. Merlin thinks clinically and never diagnoses.
Merlin does the reading for you. Bring every panel you have, from anywhere. Merlin reads each marker against both ranges and beside the ones that check it, across every system and every year, then starts you where it matters most.
If you don't feel the value of Merlin after paying for your first month, tell us and we'll refund you in full. Monthly Core, once per person, by email within 30 days. The terms
Want to see one first? Watch a real record go from the first read to the Grimoire.