Metals, toxins and medication
Arseen
Arsenic in blood shows whether you have recently taken in arsenic, usually through fish, shellfish or rice.
Everything about this testWhat it measures
The analysis measures how much arsenic is in your blood. Arsenic is a metalloid that occurs naturally in soil and groundwater. You take it in through food, especially fish and shellfish, rice and rice products. Arsenic leaves the blood quickly, so the result mainly says something about the last few days.
- Very recent exposure to arsenic, usually through food
- Exposure through drinking water from a private well in areas where groundwater naturally contains a lot of arsenic
High
A raised value is usually because you ate fish, shellfish or seaweed shortly before the blood draw. These contain organic arsenic, which the body excretes unchanged and which is not harmful. The standard laboratory test usually measures the total and cannot tell the harmless form from the harmful form. Symptoms that can go with genuine arsenic poisoning are nausea, vomiting, diarrhea, tingling in the hands and feet, and skin changes.
Low
A low or unmeasurable value is normal. The body does not need arsenic, so a low result is not a deficiency. Because arsenic leaves the blood quickly, a low value does not rule out exposure weeks or months ago.
Preparation
- Do not eat fish, shellfish or seaweed in the 3 days before the sample is taken. They contain a harmless form of arsenic that raises the result.
If your result is abnormal
With a raised result, the GP first asks about eating fish, shellfish and seaweed in the days before and, if needed, has the measurement repeated after a period without these foods. If the value stays raised, a urine test that distinguishes the forms of arsenic may follow, usually through an internist (specialist in internal medicine) or the occupational physician.
Reliability
Arsenic in blood only says something about the last few days, because the substance leaves the blood quickly; urine says more about a longer period. In people without known exposure, a single value says little. The result says something about exposure, not about a build-up that you can remove with a course of treatment. Without a distinction between organic and inorganic arsenic, a raised total value usually cannot be interpreted.
Limitations
- Fish, shellfish and seaweed in the days before the blood draw strongly raise the total value, without this saying anything about risk.
- Arsenic leaves the blood within a few days; exposure from longer ago is not visible.
- Most laboratories measure total arsenic and do not distinguish the harmless organic form from the harmful inorganic form.
- There are no agreed limit values above which treatment is needed.
How common is this
Arsenic poisoning is rare in the Netherlands. Arsenic occurs naturally in soil and groundwater, especially in river clay areas. Dutch tap water meets the standard; higher levels mainly occur in private wells that are not checked.
Who is this useful for
Useful with symptoms that suggest arsenic poisoning or with known exposure, for example through work or through water from a private well. In people without symptoms and without known exposure, the measurement adds nothing. If you eat a lot of rice or rice products, you can reduce exposure better by varying your diet than by testing.
Downsides and risks
- A raised total value after a fish meal can wrongly be interpreted as poisoning.
- An abnormal result can lead to unnecessary further testing or to treatment courses whose benefit has not been proven.
Sources
Always discuss an abnormal result with your GP. If a result is strongly abnormal, we try to reach you as soon as possible. Read your result yourself as well and contact your GP if in doubt. A test does not make a diagnosis. Read more about risks and results