What is the Thallium Blood Test?

The Thallium Blood Test measures the concentration of thallium, a highly toxic heavy metal, in the bloodstream. Thallium has no biological role in the body and even small amounts can cause significant health effects.

Exposure may occur through contaminated food or water, industrial environments, or accidental or intentional ingestion. Because thallium is rapidly absorbed and distributed throughout the body, blood testing is useful for identifying recent or ongoing exposure.

This test is typically requested as part of a toxicology or heavy metal exposure assessment.

Why do I need a Thallium Blood Test?

Thallium poisoning can present with vague or non-specific symptoms that may initially be mistaken for other conditions. Early identification is important due to the metal’s high toxicity and potential for serious complications.

You may need this test if you experience:

• Unexplained gastrointestinal symptoms (nausea, vomiting, abdominal pain)
• Hair loss or thinning
• Peripheral neuropathy (tingling, numbness, burning pain)
• Fatigue or weakness
• Cognitive or mood changes
• Skin or nail changes
• Suspected environmental or occupational exposure
• Unexplained neurological symptoms

Testing helps confirm or exclude thallium exposure as a cause of symptoms.

Benefits of the test

1. Detects toxic metal exposure
   Identifies thallium, a highly toxic heavy metal.
2. Supports investigation of unexplained symptoms
   Useful when neurological or systemic symptoms lack a clear cause.
3. Assesses environmental or occupational risk
   Relevant for industrial or contamination exposure.
4. Objective toxicology assessment
   Provides measurable blood concentration levels.
5. Helps guide further medical evaluation
   Supports decisions on additional investigations.
6. Useful in acute and subacute exposure
   Detects recent or ongoing exposure.
7. Complements other heavy metal tests
   Often assessed alongside mercury, lead, or arsenic.
8. Blood-based and reliable
   Requires a single blood sample.

Step-by-step: How we offer testing

Clinic-based testing (UK-wide)

• Choose your nearest UK clinic
• Attend your appointment
• A clinician draws a blood sample
• Sample is sent to the laboratory
• Results are issued once analysis is complete

Home or hotel visit (+£60, UK-wide)

• Book a mobile phlebotomist
• Blood sample taken at your home or hotel
• No need to attend a clinic
• Sample securely transported to the laboratory

Your results explained

Normal (no significant exposure)

• Thallium level within reference range
• UK standard: <2 µg/L
• Suggests no evidence of toxic exposure

Elevated (possible exposure)

• Thallium above reference range
• UK standard: ≥2 µg/L
• Indicates exposure requiring clinical correlation

High (toxic level)

• Significantly elevated thallium concentration
• UK standard: Markedly above 2 µg/L
• Suggests significant exposure with potential health risk