First establish that it is the same measurement
Tests with similar names can differ in specimen, method, or what is measured. A result in mass per volume and one in amount of substance per volume require a substance-specific conversion; there is no universal multiplier for every laboratory test.
Do not convert a result using a formula found for a different analyte.
The reference interval belongs with the result
Laboratories may use different methods and reference intervals. Age, pregnancy, and other factors may also affect which interval applies. Copying only the number into a spreadsheet can strip away information needed to interpret it.
MedlinePlus emphasizes that lab results are considered alongside history, symptoms, and other findings. Being outside a reference interval is not the same as establishing a disease, and being inside it does not settle every health question.
A useful comparison record
Keep the test name, value, unit, reference range, collection date, and laboratory together. If you are discussing a trend, note changes in preparation or testing conditions when relevant.
A portal graph can make two points look directly comparable even when the underlying methods differ. When the change matters clinically, the care team can help determine whether the comparison is valid before any treatment decision follows.
