Reading your blood results

Every blood result follows the same pattern. For each test you see three things: the measured value, the unit in which that value is expressed, and the laboratory's reference values. Those reference values indicate which outcomes are found in most healthy people, often broken down by age or sex.

If your value falls outside them, the report usually marks this with a flag, for example an 'H' for high or an 'L' for low. At Bloodworks, a personal explanation from a doctor sits alongside the lab values. There you read what the result means in your situation and whether a next step makes sense. Always start with that explanation; it gives the individual numbers their meaning.

A flag next to a value is a signal, not a verdict. Reference values describe what is found in most healthy people. That also means a small share of healthy people naturally fall just outside them. A slightly abnormal value can therefore be perfectly normal for you, especially if you have no symptoms.

The reverse also holds. A result in which all values fall within the limits does not rule out every condition. Not everything is measurable in blood, and some conditions only show abnormal values at a late stage. So never look at the flags alone, but at the whole picture: your symptoms, your history and the doctor's explanation.

Reference values differ per laboratory and measurement method; the values of the laboratory that tested your blood are leading. Laboratories use different equipment and techniques, and set their reference values accordingly. The same test can therefore give a slightly different outcome and a different range at one lab than at another, without either being wrong.

So only compare a value with the reference of the lab that performed the measurement. Do not simply place your result next to one from years ago at a different lab, or next to tables you find online. What is called 'normal' there may not apply to your measurement.

A single measurement is a snapshot. Blood values naturally fluctuate, for example with the time of day, what you ate shortly before, exercise, stress or an illness you have just been through. A value that falls just outside the range today can be within the limits again next week.

A repeat measurement therefore often says more than one isolated deviation. If a value remains abnormal on a second measurement, or clearly moves in one direction, that is more informative than a single number. If you re-test, do so under comparable circumstances and at the same laboratory.

First read the doctor's explanation with your result. It tells you what the deviation means in your situation and which next step is logical, from a repeat measurement to a visit to your GP. For significantly abnormal values, Bloodworks proactively contacts you.