How to read a blood test

The range printed beside your result is the interval that covers roughly the middle 95% of a reference population — usually generally healthy adults, sometimes adjusted for sex, age, or pregnancy. Two consequences follow, and they explain most lab-report anxiety.

One: about 1 in 20 healthy people fall outside a given range by definition. On a 20-marker panel, having one flagged value is the statistically expected outcome, not a warning. Two: "in range" is not the same as "optimal for you." A result that has drifted from the bottom of your personal range to the top over three years can matter even though every draw was technically normal.

Ranges also differ between labs because they use different instruments and calibrations. Comparing a value from one lab to another lab's range is a common way to scare yourself over nothing.

The same biomarker is reported in different units in different countries — glucose in mg/dL in the US and mmol/L in much of Europe, for example. Before you look anything up, check the unit on your own report matches the unit in whatever source you are reading.

Then check the conditions. Fasted or not, morning or afternoon, hydrated or not, before or after a hard training block, and which medications and supplements you took — all of these move real results. A blood draw is a photograph of one moment under one set of conditions.

Counts your red cells, white cells, and platelets. Haemoglobin and haematocrit describe how well your blood carries oxygen — low values are the usual first clue to anaemia. White cell count reflects immune activity and rises during infection. Platelets relate to clotting. A mildly high white count a few days after an illness is common and usually resolves; the useful question is whether it stays high on a recheck.

Total cholesterol, LDL, HDL, and triglycerides. LDL is the number most cardiovascular risk guidance keys on, and it is interpreted alongside your age, blood pressure, and family history rather than as a pass/fail line. Triglycerides move sharply with what you ate and drank in the previous day or two, so an isolated high triglyceride on a non-fasting draw is weak evidence on its own.

Fasting glucose is a snapshot; HbA1c estimates your average glucose over roughly the last three months, which makes it far more stable. Because HbA1c reflects red cell lifespan, conditions that shorten it (such as anaemia) can distort the result. Trending both together over time tells you more than either single value.

Creatinine is a waste product cleared by the kidneys, and eGFR is a calculation based on it that estimates filtering capacity. Creatinine tracks with muscle mass and hydration, so heavy training or a dehydrated morning draw can nudge it up without any kidney problem. Persistent change across repeat draws is what matters.

ALT and AST are enzymes released when liver cells are stressed. Intense exercise, alcohol, and some supplements and medications can raise them temporarily. Mildly elevated enzymes are one of the most common incidental findings on routine panels and often normalise on a recheck weeks later.

TSH is the pituitary signal telling the thyroid to work harder, so it moves in the opposite direction to thyroid output: high TSH suggests an underactive thyroid. TSH also varies with time of day and recent illness, which is why clinicians rarely act on one borderline value alone.

Ferritin reflects stored iron and is often the earliest marker to fall before haemoglobin does — but it rises during inflammation, which can mask a real deficiency. Vitamin D and B12 sit behind a lot of vague fatigue complaints and are worth reading alongside how you actually feel, not in isolation.

CRP is a general marker of inflammation anywhere in the body, so it is sensitive but not specific. High-sensitivity CRP is used in cardiovascular risk discussion. A recent cold, a dental infection, or a hard workout can all lift it, which is why a repeat draw when you are well is usually more informative.

The single most useful habit when reading labs is to stop asking "is this number bad?" and start asking "which direction is this number moving, and how fast?" A borderline result that has been stable across three years is a different situation from the same result arriving after two years of steady drift, even though the printed flag looks identical.

This is also how clinicians think. A one-off abnormal value on an otherwise unremarkable panel very often gets the same response: repeat it in six to twelve weeks under similar conditions and see what it does.

Self-education has limits. Contact a clinician promptly — do not wait for a trend — if a result is flagged critical or well outside its range, if you have symptoms alongside it (chest pain, breathlessness, unexplained weight loss, persistent fever, jaundice, blood in stool or urine), if you are pregnant, or if you take medications that require lab monitoring such as anticoagulants, lithium, methotrexate, or thyroid replacement.

Nothing on this page diagnoses anything or tells you to change a medication. Its purpose is to help you arrive at an appointment with better questions.

Which of these results, if any, would you actually act on? Is this value a change from my previous draws or has it always looked like this? Could a medication, supplement, or my training explain it? When should I repeat this, and under what conditions? What would make you concerned enough to investigate further?

Everything above is manual work: finding your old PDFs, matching units, lining values up by date, and separating drift from noise. That is what Ankra automates. You upload your lab reports, connect your wearable, and Ankra reads them together over time — surfacing a short weekly list of what actually moved, with a confidence level and a suggested recheck window rather than a wall of colour-coded numbers.

Ankra is not a medical device and does not diagnose or treat conditions. See how it works or the beta FAQ for accuracy and privacy details.