How soon after you draw blood from someone will it spoil?

Define "spoil"? I have heard they can obtain DNA from bones. I would think as long as it was sealed tight, whatever was in there would be there.

Probably need to tell our medical experts what drug you need to be involved. I think some may deteriorate quicker than others.<But I have no medical knowledge.>

Plot Device said:

A forensic assistant needs to draw blood from a living man to test it for drugs. He lets her. She then sticks the vial in her purse so she can bring it back to her lab for analysis. She's then fired for mishandling evidence and being a big 'ol dingdong.

How long before it spoils?

I'm assuming room temperature. And it's September in New York (not the deserts of the Sahara).

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That's just not how it'd work, so I don't think 'spoilage' is your issue. I also think the accuracy is what your issue would be and that'd largely depend on what you're testing for, afaik.

Plot Device said:

I knew a guy a few years ago who got a job as a courier for a lab. He had to drive around to dozens of medical practices every night to pick up all the little vials and jars that got placed into those funny little specimen boxes you see down on the hallway floor outside your doctor's office. He said he was absolutely not allowed to be late because if he was late, and the building got locked for the night, then the specimens would all go bad before morning. And then the patients would need to get called back to the doctor's office all over again to hand over yet another specimen.

I want to know how long that window of time is.

Any specimen couriers in the house?

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I'm not positive, but I think that's probably different, and also about what's being tested, same as the drug thing.

There are doctors about, maybe one would know?

Also, that's funny they're in buildings some places - here, they're usually outside, probably for that reason (so they don't get locked in).

It's not so much how long the blood will be testable as for how long the drugs will be detectable.

There are two complications; first is that there is no single blood draw tube, but many. And each has a different set of additives that do things to the blood in order to make the blood is preserved in the right way for the kind of testing that needs to be done (preserving this and that, clotting, or preventing clotting, separating, etc.).

If your MC doesn't have or use the right kind of tube, that can cause trouble. Does she regularly draw blood? If she's doesn't have that history, she could screw it up. And the type of tube she needs, and the amount of refrigeration and processing it wants will depend on the drugs she's searching for. She might actually need multiple samples.

Second, if your character wants to use the blood samples for official evidence, then she'd want to get it on ice right away. If it's just for her information, that's a different matter.

As to your actual question--I found some suggestion that the type of tube with the additive used for toxicology should only sit out at room temperature for 4 hours (though that's using the blood for a different kind of test). Note that's probably the being careful so they don't screw up guidelines. But I've also found something that blood samples in a police car's trunk could sit for 7 days at or above room temperature while having only a minor affect on BAC.

So you're probably fine, but it really depends on what she wants to use it for.

Does it actually have to be in her purse? If she takes it in the hospital, I'd assume there are better ways to transport it to elsewhere in the hospital? I might even guess that someone could deliver it to the lab and put it in the refrigerator for her. If there are plot reasons that it needs to be in the purse, then okay. But it would seem really odd to me that some sort of medical professional, in a hospital, would take a vial of blood and put it in her purse.

If it does need to be in the purse for some reason, she could still refrigerate it. A hospital is going to have some icepacks--though those wouldn't stay cool the whole time, they should at least extend viability.

I think you need to know which drugs you want to use in your story, then check out their decay rates. But if they were detectable in the dead guy, then you have at least the same amount of time as elapsed between him being drugged and him being autopsied.

Why do you need the specificity you seem to ask for? Can't a brief paragraph that she drew the blood and took it to the lab work? Then find whatever you need for your story.

Or do you need the sample to get tainted for your story so it doesn't match?

Jeff

They use a red top tube and the blood is supposed to clot. Don't worry about blood "spoiling" in a couple of hours, they can still do toxicology. How else would they be able to do toxicology on the dead?

Your problem will be the type of drug. What is the drug? (And don't say succinylcholine aka "Sux".)

Simple answer to your question, blood Will clot in 2-5 minutes, depending on volume on e removed from a vessel. My problem with what you described, is if he is in a hospital, she would never be allowed to simply take blood from him. As someone said many different tubes with different preservatives would make a difference. Does she have all the equipment in her purse to draw blood? Catheter, syringes, tubes, torniquet? If she wants to prove he has the same drug in his,system as your victim, why not just ask the hospital to draw the specimen?

I too wondered if she was just stealing hospital supplies and how she thought she'd get away with finding, stealing and using them without anyone noticing.

I also wonder if she knows how to draw blood.

I prefer to drink it while it's still warm, but it should stay good for a couple days in the fridge. I'd suggest re-heating it in the microwave for about 2 minutes at 50%.

Hey,

I am new round these parts.

Perhaps your MC is on good terms with a doctor at the hospital. If satisfied of patient consent, he might do the deed for her and handle submission of the sample for testing.

Tidy