Metals, toxins and medication
Lood
The amount of lead in your blood; a measure of exposure to lead through water, work, hobbies or the environment.
Everything about this testWhat it measures
This test measures how much lead there is in your blood, in micrograms per liter. Lead is a heavy metal that occurs everywhere in the environment in small amounts and is toxic to the body. Of the lead you take in through food or drink, an adult absorbs about a tenth, a child up to 6 years old much more. The absorbed lead spreads over the blood, the organs and especially the bones, where it can stay for years and later be slowly released again.
- Increased exposure to lead, for example from old lead water pipes, work or a hobby
- Lead poisoning with symptoms that fit it
- Monitoring the effect of measures or treatment after too high an exposure
High
A raised value means you have been exposed to lead recently or for a long time. Stricter limits apply to children and pregnant women than to other adults. The higher the value, the more important it is to remove the source of exposure; with a strongly raised value, urgent treatment is needed. Symptoms that can go with a high lead burden are tiredness, headache, abdominal pain, nausea, weight loss and anemia; in young children it is mainly about effects on development. Common sources are lead water pipes in buildings from before 1960, work with batteries, demolition or old paint, and hobbies such as stained glass, shooting or casting lead objects.
Low
Almost everyone has a small amount of lead in their blood; it mainly comes from food. A low value means that exposure is small at present. According to the RIVM (Dutch National Institute for Public Health and the Environment) and the EFSA, there is no value below which lead certainly has no effect, but at the average exposure in the Netherlands, the risk for adults is considered low to negligible. A low value in the blood does not rule out that there is still lead in the bones from an earlier period of high exposure.
If your result is abnormal
With a raised value, the main thing is to find and remove the source, for example by replacing lead pipes or making changes at work. The GP can repeat the measurement with blood from a vein and, if needed, consult the occupational physician or the environmental health department of the GGD (municipal public health service). With very high values, you are referred to an internist (specialist in internal medicine), because treatment with medicines that bind lead may then be needed.
Reliability
Lead in blood is the usual measure of exposure and can be measured well, but it is a snapshot: the value mainly follows exposure over the past weeks to months. Lead stored in the bones is not measured by it. According to the Dutch Society for Clinical Chemistry (NVKC), a raised result from a finger prick must always be repeated with blood from a vein, because lead from the skin can get into the sample. When lead poisoning is suspected, zinc protoporphyrin is sometimes also measured, because lead disturbs the production of hemoglobin.
Limitations
- A finger prick can give a result that is too high due to lead on the skin; confirmation with blood from a vein is needed.
- The value says little about exposure years ago, because the lead is then in the bones.
- Children absorb much more lead from food than adults; lower limits apply to them and to pregnant women.
- Reference values and measuring methods differ by laboratory.
How common is this
Exposure to lead in the Netherlands has fallen sharply since lead disappeared from petrol and paint and lead water pipes were replaced. In children, blood lead levels have more than halved since 1979; in a study among 250 children in Rotterdam, the median value was 18 micrograms per liter, with outliers up to 103. Buildings from before 1960 may still have lead pipes, which can bring the lead content of tap water above the standard of 5 micrograms per liter.
Who is this useful for
Useful if you suspect you take in more lead than average: with lead water pipes in an old house, with work involving lead or a hobby that releases lead, and with symptoms that fit a high lead burden. Also useful for risk groups in such a situation: young children and pregnant women are the most sensitive. Without a sign of exposure, measuring yields little, because virtually everyone has a low, normal value.
Downsides and risks
- A slightly raised result from a finger prick can be caused by contamination of the sample and, without a check measurement, cause unnecessary worry.
- A normal value does not rule out an earlier high exposure, because lead accumulates in the bones.
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