When you go to give blood, you’re screened for risk factors that could make the donation unsafe. Donations are also tested for bacteria, viruses, and such – tests which must all be negative before the blood can be used for a transfusion.

But if a new study is correct, some pathogens from people with advanced gum disease may still make it through, raising the question of whether periodontitis is a specific risk factor that should be screened for.

The study, published earlier this month in the journal Blood Transfusion, involved 60 healthy adults over age 50. Each had a periodontal exam with x-rays. Each provided a sample of blood, which was separated into plasma, red blood cells, and buffy coat (the part of the blood that contains the most white cells and platelets after being centrifuged). The plasma and red cells were incubated, while a system called BacT/Alert was used to screen the buffy coat for bacterial contamination.

As Dr Bicuspid reported,

In all, 48% of the blood donors had periodontitis. Of those with gum disease, 62% showed bacterial growth on at least one out of four plates inoculated with plasma or red blood cells. Only 13% of plates inoculated with plasma or red blood cells from those without periodontitis yielded bacterial growth.

“The prevalence of bacteria,” they added, “was 6.4 times higher in blood donated by people with periodontitis compared to those who didn’t experience severe gum inflammation.” More, in the words of the researchers themselves, exactly “none of the donors tested positive for bacterial contamination using BacT/ALERT.”

None.

“This,” wrote the study authors,

suggests that blood donors with periodontitis are considerably more likely to donate blood contaminated with bacteria, and that routine screening of platelets using BacT/ALERT may not be sufficient to detect contaminations that may cause TTI [transfusion-transmitted infections].

Why the contamination? As the study’s lead author explained in a recent news release,

The presence of periodontitis implies having a large infected wound from which bacteria can enter the circulation. Every time you brush your teeth or chew food, the periodontal bacteria have direct access to the circulation.

What’s unclear at this point is the clinical significance of these new findings. And the authors stress that receiving donor blood remains generally safe. For one, there’s all the testing.

Also, the immune system will protect the patient from bacteria in the transfused blood. However, not all infections are reported to the blood bank. It is therefore important to identify risk factors that can lead to bacterial contamination, e.g. periodontitis – especially because donors do not necessarily consider periodontitis a factor worth mentioning when interviewed.

‘In our experience, blood donors make sure to mention any diseases that may affect the quality of the blood. But few consider periodontitis a relevant disease; therefore, most donors probably do not mention it to the blood bank’, says [Dr.] Susanne Gjørup Sækmose and continues:

‘Our study suggests that we may have to develop new methods for efficient screening of donor blood in the future. But really, the most important point is to make sure that everyone sees the mouth as a part of our organism. Basically, diseases in the mouth may affect our overall state of health’.

We couldn’t agree more.

Image by Bryan Jones

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