Arsenic (As)
Trace elements can be essential or toxic. Trace element toxicity can occur as a result of occupational exposure, environmental exposure or iatrogenic toxicity. Any organ can be affected: the central nervous system, liver, kidneys, muscles or circulatory system. All elements can be toxic in excess.
Those most commonly associated with toxicity include: aluminium, lead, arsenic, cadmium, mercury, and thallium.
Arsenic poisoning is generally caused by ingestion and can lead to the onset of gastrointestinal pain, vomiting, shock, diarrhoea, neuropathy and renal failure.
Ingestion of seafoods (fish, shellfish, seaweed) will cause an increase in blood and urine arsenic due to the presence of non-toxic organic forms of arsenic compounds. These foods should be excluded from the diet for several days before sampling.
| Blood |
| 14 – 95 nmol/L |
| Urine |
| 160 – 213 nmol/L |
| <12.9 nmol/mmol creatinine |
| <6.1 µmol/24hr |
Diets rich in seafood give misleading results (several thousand nmol/L have been reported) due to presence of non-toxic organo-arsenic compounds.
Exclude seafood from diet for five days prior to sampling.
Record last updated
September 3, 2025
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6ml Trace Metal Silica (Navy blue top with purple band on label)
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4ml EDTA Vacutainers (Lavender top)
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6ml Lithium Heparin (Green top)
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24hr Urine Bottle (Plain label)
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Test Results
Yes, we have a Pathology User Guide
Yes. Please email your request to Imperial.nwlpcustomerservice@nhs.net
Results are communicated to clinical staff and are normally not communicated direct to patients either on telephone requests or in written report. If you need to contact us please click here to view the contact details page
Please contact the Customer Service Team Monday to Friday from 8:30am – 6:00pm on 0203 313 5353. Alternatively, see the Pathology User Guide for how to contact the relevant department. If advice is not urgent you can also email your query to Imperial.nwlpcustomerservice@nhs.net
Additional tests may be added by discussion with the relevant laboratory. The time limit for adding additional tests to a sample already received in the laboratory will depend on the type of sample and the department it was sent to.
Information on the repertoire of tests performed by pathology, including reference ranges, turnaround times and specimen requirements, can be found in the test directory.
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Imperial College Healthcare Trust Phlebotomy services
Chelsea and Westminster Hospital NHS Foundation Trust Phlebotomy services
NWLP operates UKAS accredited medical laboratories as per the references below. The current scope of accreditation for all NWLP’s laboratories can be found on the UKAS website.
See the following UKAS ref numbers:
- Clinical Biochemistry Ref: 8673
- Haematology and Blood Transfusion Ref: 8674
- Infection & Immunity Sciences (Including Immunology, Virology, Microbiology and Histocompatibility and Immunogenetics ) Ref: 8659
- Cellular Pathology (Including Histopathology, Cytology and Molecular Pathology) Ref: 9615
If you require copies of our certificate of accreditation and associated documentation please contact Imperial.nwlpcustomerservice@nhs.net.
UKAS requires the laboratories to be accredited for a particular repertoire/scope (ISO15189), any changes or additions to repertoire require assessment by UKAS (extension to scope).
The BD Hospital Tube Guide, BD GP Tube Guide and BD Paediatric Tube Guide provide visual references to the correct tube types and collection instructions.
Home testing
INSTRUCTION SHEET FOR BLOOD SAMPLE COLLECTION
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Our accreditations
Upholding excellence in diagnostic standards
Our laboratories are accredited by the UK Accreditation Service (UKAS) against the international standard ISO15189:2022. UKAS is the accreditation body for the UK that assesses medical laboratories.
Find out more about our accreditations on the UKAS website.
UKAS website