Infections
Difterie antitoxinen
Antibodies against the diphtheria toxin; show how well vaccination protects you, not whether you have diphtheria.
Everything about this testWhat it measures
Diphtheria is an infection with the bacterium Corynebacterium diphtheriae or a related species, which can make a poison (toxin) that damages the throat, heart and nerves. Vaccination teaches the body to make antibodies against this poison, called antitoxin. In the Netherlands, the vaccination has been part of the National Immunization Program since 1957, as part of the DTaP-IPV shot (DKTP). The test measures the amount of antitoxin in the blood in international units per milliliter (IU/ml) and so says something about protection, not about an infection.
- The level of protection against diphtheria after vaccination
- Insufficient protection, where an extra vaccination may be useful
High
According to the LCI guideline (RIVM) on diphtheria, a value of 0.1 IU/ml or higher counts as fully protective. A high value fits a vaccination given not long ago; after a booster shot the amount of antitoxin rises sharply. A high value is not a sign of disease and causes no symptoms. Over the years the value gradually falls again.
Low
According to the LCI guideline (RIVM), a value below 0.01 IU/ml counts as not protective; between 0.01 and 0.1 IU/ml there is some protection. A low value mainly occurs if the last vaccination was long ago, in older people who received fewer vaccinations as children and in people who are not or incompletely vaccinated, for example because they grew up in another country. A low value does not mean you have diphtheria; it is a sign that a booster shot may be useful, especially before traveling to an area where diphtheria occurs.
If your result is abnormal
With a value below the cut-off for protection, a booster vaccination can be given, through the GP, the GGD (municipal public health service) or a travel vaccination clinic; sometimes the value is measured again a few weeks after the shot. If diphtheria itself is suspected, other tests are needed; diphtheria is notifiable (group B1).
Reliability
The LCI guideline (RIVM) on diphtheria gives cut-off values for protection: below 0.01 IU/ml not protective, from 0.01 IU/ml some protection and from 0.1 IU/ml fully protective. The test measures antibodies in blood and, according to the guideline, is not suitable for showing a diphtheria infection; that requires a culture or PCR of the throat or wound. The result is a snapshot and says the most when there is doubt about the vaccination history.
Limitations
- Laboratories use different measurement methods; especially around the cut-off values, results can differ between methods.
- The test says nothing about a current diphtheria infection.
- After a blood transfusion or treatment with immunoglobulins, antibodies from donors may temporarily be measured as well.
- With reduced immunity, the amount of antibodies says less about the actual protection.
How common is this
Diphtheria is rare in the Netherlands thanks to vaccination in the National Immunization Program. Between 2011 and 2021, 18 cases were reported, 0 to 4 per year, almost all of them a skin infection. In 2022 there were 7 cases and in 2023 there were 14, mainly in people who had recently come to the Netherlands.
Who is this useful for
The result says the most when you are unsure about your own vaccination history, for example in people who grew up in another country or whose last shot was long ago, before traveling to an area where diphtheria occurs, and with work involving people from such areas. For those who have fully followed the National Immunization Program and have no special exposure, the result changes little. The test is not meant to assess whether symptoms are caused by diphtheria.
Downsides and risks
- A low value can cause worry, while diphtheria is very rare in the Netherlands and a booster shot is simple.
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