# If a droplet of blood disperses in water you have HIV? **URL:** \ **Category:** Factual Questions\ **Created:** [December 8, 2005, 9:43pm UTC](https://boards.straightdope.com/t/if-a-droplet-of-blood-disperses-in-water-you-have-hiv/334760 "2005-12-08T21:43:41Z")\ **Posts on this page:** 7\ **Page:** 1
**Author:** ![riot8ap](https://avatars.discourse-cdn.com/v4/letter/r/ecccb3/32.png) [@riot8ap](https://boards.straightdope.com/u/riot8ap)\ **Post date:** [December 8, 2005, 9:43pm UTC](https://boards.straightdope.com/t/if-a-droplet-of-blood-disperses-in-water-you-have-hiv/334760/1 "2005-12-08T21:43:41Z")
OK, I’m sure this is a bunch of hokie-pokie but I told my brother you guys know it all. Situation: My brother in construction was working with some people from Honduras and the issue wase raised somehow of a low-tech test for HIV. Basically these Hondurans said if you prick your finger and drop a droplet of blood into a cup of cold water you will have either of two scenarious. Scenario 1: The droplet stays together in little balls and sinks to the bottom of the cup. This means you are not infected. Scenario 2: The droplet disperses and kinda clouds like as if it were like food coloring. This means you have HIV. My thoughts were that maybe it has to do with how hydrated you are at the moment, along with platelete count. What’s your take? ---
**Author:** ![olpeculiar](https://avatars.discourse-cdn.com/v4/letter/o/34f0e0/32.png) [@olpeculiar](https://boards.straightdope.com/u/olpeculiar)\ **Post date:** [December 8, 2005, 9:56pm UTC](https://boards.straightdope.com/t/if-a-droplet-of-blood-disperses-in-water-you-have-hiv/334760/2 "2005-12-08T21:56:28Z")
The test you describe sounds just like one of the screening procedures that are performed before you donate blood (at least 'round these parts). Prick the finger, drop of blood in the blue water, and watch the reaction. But it’s not a test for HIV - it is a display of the blood’s iron or red blood cell content (can’t remember which). Blood with a high content (like mine) stays together and drops like a stone to the bottom of the vessel. Other, less-rich blood drops will tend to disperse. Too anemic (or iron-poor or whatever), and you’re not allowed to donate. I’m not a medical type, but I’ve never heard of blood with higher water-solubility being a sign of HIV infection. Of course, my ignorance doesn’t rule out the possibility… ---
**Author:** ![Ethilrist](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/ethilrist/32/4604_2.png) [@Ethilrist](https://boards.straightdope.com/u/Ethilrist)\ **Post date:** [December 8, 2005, 10:01pm UTC](https://boards.straightdope.com/t/if-a-droplet-of-blood-disperses-in-water-you-have-hiv/334760/3 "2005-12-08T22:01:22Z")
Last I heard, the only reliable test for the presence of HIV was an HIV test, administered by a trained professional. Going about sticking oneself in the finger and putting drops of blood in water seems more than a little counterproductive. ---
**Author:** ![chrisk](https://avatars.discourse-cdn.com/v4/letter/c/6de8d8/32.png) [@chrisk](https://boards.straightdope.com/u/chrisk)\ **Post date:** [December 8, 2005, 10:12pm UTC](https://boards.straightdope.com/t/if-a-droplet-of-blood-disperses-in-water-you-have-hiv/334760/4 "2005-12-08T22:12:00Z")
I think it sounds extremely fishy on the face of it… considering how much of the virus would be in a drop of blood, it’s almost impossible that it would affect solubility very much. ---
**Author:** ![Vlad\_Igor](https://avatars.discourse-cdn.com/v4/letter/v/7feea3/32.png) [@Vlad\_Igor](https://boards.straightdope.com/u/Vlad_Igor)\ **Post date:** [December 8, 2005, 11:10pm UTC](https://boards.straightdope.com/t/if-a-droplet-of-blood-disperses-in-water-you-have-hiv/334760/5 "2005-12-08T23:10:56Z")
> [@olpeculiar](#): > > The test you describe sounds just like one of the screening procedures that are performed before you donate blood (at least 'round these parts). Prick the finger, drop of blood in the blue water I believe the solution is copper sulfate, not water. Blood in plain water will simply disperse, regardless of what’s in it. When blood hits water, the red calls, white cells and platelets in it will swell due to osmosis (i.e. water moving into the cells in an attempt to lower the salt content to match the salt content of the surrounding water - which is 0). After a few minutes, those cells will burst. If the AIDS virus was present, it would be released from the white cells and promptly fall apart. The virus is fragile, and doesn’t tolerate being outside of the blood for more than a short length of time. This explains in part why so few cases of AIDS has come from casual contact, and why the most common way the virus is spread is through direct contact with the blood, lymphatic sysytem or mucous membranes. In contrast, someone with a cold or flu can infect others through casual contact or aerosols (sneezing or coughing). The polio virus can survive in the environment (dirt, excrement) long enough to infect someone else who comes along later. Vlad/Igor ---
**Author:** ![Smeghead](https://avatars.discourse-cdn.com/v4/letter/s/f1d935/32.png) [@Smeghead](https://boards.straightdope.com/u/Smeghead)\ **Post date:** [December 8, 2005, 11:27pm UTC](https://boards.straightdope.com/t/if-a-droplet-of-blood-disperses-in-water-you-have-hiv/334760/6 "2005-12-08T23:27:19Z")
> [@riot8ap](#): > > What’s your take? NO! ---
**Author:** ![nagrom1995](https://avatars.discourse-cdn.com/v4/letter/n/41988e/32.png) [@nagrom1995](https://boards.straightdope.com/u/nagrom1995)\ **Post date:** [December 9, 2005, 8:47pm UTC](https://boards.straightdope.com/t/if-a-droplet-of-blood-disperses-in-water-you-have-hiv/334760/7 "2005-12-09T20:47:00Z")
Unless you have access to sterile nedles (wich most people don’t)you run the risk of getting tetnus or other types of infections.So i suggest you **DON’T** try it!