Why do lab results vary between different labs?

It’s good to note first that reference ranges vary by lab, meaning that different labs may yield different results. That is normal. Variability can occur due to differences in testing equipment, chemicals used, and analysis techniques.

Interpreting Your Results

This variability is the reason you should use the reference range supplied by the lab that analyzed your test to evaluate whether your results are within normal limits. We recommend you use the same laboratory each time you have your labs drawn, as consistency is key when it comes to identifying trends and the effectiveness of any interventions you're using.

Variability of Results

We recommend to stay consistent by testing at the same time. Here is some data that shows just how much TSH, for example, can vary just over the course of a 24-hour period:

Efficacy of Results

Every lab must demonstrate that their results meet a common standard to ensure an acceptable level of precision with their reporting.

We have ensured that all the labs we use meet and/or exceed the minimum standard for acceptable variation; though you will always see some degree of variation in results between different labs.