What are reference intervals?
When you have been for a test (for example a blood test), your sample will be taken to a laboratory to be processed to find out the results. The results that come back will have been measured against a reference interval, which is a guide. Usually this will be stated along with your test result so it’s easy for your doctor (and any other health professional) to interpret the result.
It’s important to know about reference intervals because they can vary from country to country, region to region and even between individual laboratories. Test results may also be affected by more specific factors such as time of day, fasting or non-fasting, rest or activity, gender, age, pregnancy, menopause, supplements or medications. Some hormones have very narrow reference intervals, and some have very wide. If you want to understand more about your results, speak with your endocrinologist, endocrine nurse, or general practitioner.
You can find out more about how reference intervals are worked out here.