Why do my results have different reference ranges?

Reference ranges are set by the laboratory that analyses your sample, so they can differ between tests. We work with two main laboratories, and each sets ranges based on the testing methods and equipment it uses, and often on results from a large group of healthy people. Labs also update their ranges from time to time, for example when they introduce new equipment or follow updated clinical guidance. Some markers use ranges set by national guidelines rather than lab-specific ones.

This means a change in reference range doesn’t mean your previous result was wrong. Always read each result against the range shown alongside it. If you’re comparing results over time, look at where each one sits within its range, and check the units are the same.