Selenium (Serum)
Selenium is an essential trace mineral that plays a critical role in antioxidant defence, immune regulation, thyroid hormone metabolism, and cellular protection. Although required only in small amounts, selenium is vital for the proper functioning of multiple biological systems. It forms an integral component of selenoproteins, including glutathione peroxidase and iodothyronine deiodinases, which protect cells from oxidative stress and support thyroid hormone conversion. Serum selenium testing measures circulating levels of this micronutrient to assess adequacy or detect deficiency or excess. Because selenium status can vary depending on dietary intake, geographical soil content, and underlying health conditions, laboratory assessment provides objective insight into nutritional balance.
- Price: £97
- Code: SEL
- TAT: 3 Working Days
- Sample Type: Blood
Clinical Significance
Selenium contributes to antioxidant protection by helping neutralise harmful free radicals that can damage cell membranes, DNA, and proteins. Low selenium levels may impair immune response, reduce antioxidant capacity, and influence thyroid function due to its involvement in the conversion of thyroxine (T4) to triiodothyronine (T3). Deficiency has been associated with fatigue, weakened immunity, cognitive changes, and in rare cases, cardiomyopathy such as Keshan disease. Suboptimal selenium may also impact fertility and reproductive health. Conversely, excessive selenium intake may lead to toxicity (selenosis), characterised by hair thinning, nail changes, gastrointestinal disturbance, and neurological symptoms. Because both deficiency and excess can have clinical consequences, accurate measurement is important when supplementation is being considered.
Who Might Benefit From This Test?
This test may be appropriate for individuals with suspected micronutrient deficiency, thyroid dysfunction, chronic inflammatory conditions, or unexplained fatigue. It may also be useful in patients following restricted diets, those with malabsorption disorders, or individuals taking long-term nutritional supplements. Clinicians may request selenium testing as part of a broader nutritional assessment or thyroid evaluation, particularly where symptoms persist despite normal standard thyroid markers.
Sample Collection
A blood sample is collected by a trained healthcare professional in a clinical setting. The procedure is quick and minimally invasive. Samples are processed in accredited laboratories using validated trace element analysis techniques to ensure accurate quantification.
Understanding Your Results
Results are interpreted within the context of dietary intake, clinical symptoms, and related laboratory findings. Low levels may prompt dietary modification or supplementation guidance, while elevated levels may require review of supplement use. Because selenium interacts with other micronutrients and thyroid hormones, interpretation considers the broader metabolic picture. Follow-up testing may occasionally be recommended to monitor correction or ensure safe supplementation.
FAQs
When will I receive my results?
Results are usually available within the stated turnaround time.
Should I discuss my results with a doctor?
Yes, results should always be reviewed with a qualified healthcare professional.
Why Choose Marylebone Diagnostic Centre?
Marylebone Diagnostic Centre offers comprehensive micronutrient and endocrine testing in a professional and discreet environment. With a turnaround time of 3 days, this test provides reliable assessment of selenium status to support personalised nutritional and metabolic care.
Book Now
Book the Selenium (Serum) (SEL) test today to support optimal nutritional balance and thyroid health.
