How to prepare
No fasting is required for this test. Drink water as normal beforehand.
If you take selenium supplements, let your practitioner know. You may be advised to pause supplementation before the test to get an accurate baseline. High-dose selenium supplements can push levels into a toxic range, so this test is worth doing before and during supplementation. A healthcare professional will take a blood sample from a vein in your arm.
After the test
Share your results with your GP, endocrinologist, or a practitioner familiar with thyroid or nutritional health. If selenium is low and you have a thyroid condition, your practitioner may discuss whether selenium supplementation is appropriate for your situation and at what dose.
If you are currently supplementing selenium, use this test to confirm your levels are within a safe and optimal range. Selenium has a narrow therapeutic window, so regular monitoring during supplementation is sensible.
Your test results will be available in your private dashboard. If there are any urgent issues, we'll let you know so you can follow up with your health professional.
Understanding results
Results are reported in micromoles per litre (umol/L). Reference ranges vary between laboratories; your result report will include the applicable range.
Low serum selenium can be associated with poor thyroid hormone conversion, reduced antioxidant activity, impaired immune function, and muscle weakness. Australian soils are variably selenium-depleted in some regions, which can result in lower dietary selenium intake depending on where food is grown and sourced.
High serum selenium, usually from excess supplementation, can cause selenosis — a condition characterised by hair loss, nail changes, fatigue, and in severe cases, neurological effects. This test helps ensure supplementation remains within a safe and useful range.
Your practitioner will interpret your result alongside thyroid markers, dietary history, and any other relevant investigations.
