If a lab says that creatinine is 1.10, it may or may not be elevated based on the reference range. Why are labs like this?
In: Biology
Are you asking why different analytes (like creatinine, or everything from liver enzymes to CRP to specific antibodies) have different reference ranges? Or are you asking about variation in testing results between different laboratories?
The answer to the former is because different analytes are present in different amounts in healthy people who were tested to establish those reference ranges.
The answer to the latter is that there is always some random noise inherent in biochemical tests, and small factors in different labs’ procedures may nudge it in a particular direction. Good lab practices and standardized testing materials can minimize that.
E: creatinine at 1.1 (assuming mg/dL) is just about on the high side of its usual reference range. Given some random noise in the measurement, you could think of that as “possibly normal, possibly slightly above normal”.
different people have different baselines. this can be for defined medical reasons, or because we’re complicated meat machines that all run a little different.
a fairly common example is body temperature. 99F is above the norm, but isn’t usually regarded as a fever. but for a patient that naturally runs cooler than average, a persistent temperature of 99 could mean an infection.
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