Lab results are not a verdict or a diagnosis β they are data that need to be read correctly. The same marker can fall outside its reference range for a dozen reasons, from how you prepared for the draw to the lab's own methodology. This reference covers markers one at a time: what the test measures, which values count as normal, why a result runs high or low, and which steps are worth discussing with your doctor.
The reference is growing. If the marker you need isn't here yet, browse the Analyses & Diagnostics category for in-depth guides by marker group.








