I thought it took weeks.
But in this front page case the suspect was just found yesterday.Police: DNA Matches in Judge Kin Killings
It’s pretty quick, actually. You could do everything in a matter of hours.
If it takes weeks in some places, that’s because there’s a backlog of other jobs to be done in the lab. Or there’s been a screw-up, so someone needs a new sample, or something. But I assume that the second case is really pretty rare.
If CSI is any guide; one commercial break.
You have to transfer the evidentiary sample and the reference sample from each collecting agent to the main evidence custodian, then to the laboratory’s custody agent, then to the laboratory technician, all while maintaining legally defined chain of custody. Then you have to do the test in a process that separates it from all other tests in a legally defendable standard method that is documented by every participant. Then you have to send back your results in a similar chain of custody. That is ideally supposed to happen to two separate samples from each source whenever possible, and include two different laboratories. In addition, a complete separate set of both samples are supposed to be maintained by the central evidence custodian, in case the tests need to be repeated, and all those samples have to be referenced as to location, and agents who had custody during the chain.
Then there are government holidays, weekends, and lawyer’s hours to consider. Tomorrow is next week. Next week is about a month from now, and next month could be in a year, or two.
Oh, yeah, and the test takes half a day, too. Sometimes more.
Tris
When one was run on me, it took six weeks, but then it had to go back to the States. On the other hand, Saddam H (and his sons) were done in a couple of hours. A matter of priorities I suppose.
Yeah, the actual sciency part of it should only take less than an hour to a few hours, depending on what equipment and procedures their using.
Be careful. Three lights on a DNA match is bad luck.
They’re. Ye gads. I’ll go punish myself.
Smeghead - I’m glad you cleared that up, I was kwite cornfused byt the tipo. 
When I first did DNA fingerprinting (a simplified version for an advanced high-school lab, but still based on VNTRs), I was surprised by how little time the procedure took. I had also always heard of fingerprinting taking weeks, but it was done in a few hours. This is true of other fingerprinting techniques, too. It takes an hour to a few hours, at the most, to amplify the sample using PCR (a technology that makes copies of DNA by varying the temperature of a mixture of the sample, an enzyme that copies DNA, and the raw materials needed for making DNA). Then, it takes about an hour or two to process the sample with restriction enzymes that cut up the DNA in specific ways and to separate the resulting DNA fragments by weight or size using a electrically-charged gel (electrophoresis).
DNA fingerprinting takes weeks for the same reason it takes weeks to get a tax return or the results of a medical lab test. Crime labs have a lot of samples to analyze, and Triskadecamus has explained the details of the bureaucratic and legal factors that slow down the process. When it’s urgent, though, as it was for Saddam Hussein (where it was deemed unwise to release the news to the world before a DNA match was made), it’s possible to obtain results in a few hours.
Also, there is the fact that doing police DNA testing is the bottom of the economic barrel as far as commercial lab use goes. The same personnel and equipment can make you a lot more money if you use it to provide Medicaid approved health testing in the open market. As a result, Virginia recently got its second laboratory, state wide that is authorized to do forensic DNA testing.
Tris