Why we ask such a question? We may unconsiously touch a dried blood whether we know or not  whose blood is that. Especially if we know that is blood of a patient who has certain diseases. The real anxiety is coming from the general knowledge that a disease can be spread through blood. That is true. But the question is does the dry one also carry diseases?

We know several diseases which may spread through blood or body fluids. The most common, also the most scary ones are HIV, hepatitis B and C. Let’s find out the possibility of these disease of being spread through the dried blood.

Dried blood and HIV

It is true that in certain conditions viruses can survive for a few days to weeks outside our human body. But it is affected by some factors such as volume of body fluid, concentration of virus in the fluid, the temperature, acidity and the sun exposure.

It is important to bear in mind that although HIV is transmitted through blood, it needs all of these conditions :

• The blood or other body fluids (include semen, vaginal secretions, cerebrospinal, synovial, pericardinal, peritoneal etc.) containing high level  of HIV.
• An activity with a high risk such as sharing the same needles.
• No exposure of air, since HIV is a weak virus which dies if it is exposed to the air.

In addition, to be in contact with dry blood which contains HIV is not enough to spread the virus because :

1. The virus may have die.
2. If the quantity of dried blood is in a small amount, it is almost useless to be worried for.
3. HIV spread through blood only if the blood contains HIV has a direct access to the bloodstream. So a touch or even a small cut in your finger when touching the dry blood will not make something occur. Unless you have a very deep cut or it is heavily bleeding when the cut has a contact with the dry blood.

Dried blood and Hepatitis B and C 

Let’s start with the facts that hepatitis  B virus can survive in a dried blood for up to  a week, and hepatitis C virus can survive no more than 4 days.

Although there are such possibility, again, other conditions are still needed. The volume of body fluid (in this case died blood), concentration of virus in the fluid, the temperature, acidity and the sun exposure.

In addition, have contact with dry blood which contains hepatitis B or  C  is not enough to spread the virus, unless there is a blood to blood contact such as a deep injury which result heavy bleeding in contact with the virus within the dried blood (if it still survives).

But it does not mean you can ignore all of dried blood around you. You can do these things to lessen the risk of being infected :

• Using a glove and disinfect surfaces that have been in contact with dried blood.
• If you live or take care of a hepatitis B or C patient, use gloves anytime you have to do something.
• Toss the gloves after you clean the dried blood or another fluid from a patient of hepatitis B or C.

So the answer to the question on the title is : yes, dry blood does carry disease since some virus can survive outside the body. But, there is one thing to be kept in mind : the disease, or more specific, the virus within the dried blood also needs some conditions to be transmitted to another person who is in contact with the blood. Most of viruses need a blood to blood contact, not simply blood to skin contact. In the case of HIV, the blood to blood contact means that the dried blood has to have a direct access to the bloodstream of a person.

It means that the risk of being infected by a virus through the contact with dried blood is almost zero, but still, you have to be aware. If you still in doubt whether you are get infected or not, you are highly recommended to consult with the professionals and take some examination to make sure yourself.