baseline
Meaning of baseline: A baseline is an initial measurement recorded before a condition or treatment begins, providing a reference point for detecting change over time.
Definition of baseline
A baseline is an initial measurement or observation recorded at an early point, typically before a treatment begins or before a condition is expected to change, so that later measurements can be compared against it. Establishing a baseline provides a clear reference point for judging whether a meaningful change has occurred.
Baseline measurements are used throughout medicine, including baseline vital signs and laboratory values recorded before a procedure, and baseline imaging of a tumor recorded before treatment begins, against which later scans are compared to judge whether the tumor has grown, shrunk, or stayed the same.
Because interpreting change depends on having an accurate starting point, a baseline measurement is generally recorded using the same method later used for comparison, since a difference in how a measurement is taken can itself produce an apparent change that does not reflect any real difference in the underlying condition.
Used in a sentence
Baseline laboratory values were recorded before the treatment began.
Good to know
A meaningful comparison to baseline depends on using the same measurement method both times, since a change in technique between the baseline and a later measurement can create an apparent difference that is not a genuine change.