View Full Version : What's the fastest I can realistically have paternity results?

04-19-2016, 11:23 AM
Hello, all.

One of my characters wants to have a discreet paternity test done. For story purposes, I'd like this to happen as fast as possible -- ideally, within 24 hours or less.

The characters will be providing a cheek swab (potential father) and a toothbrush (teenage boy) sample.

In looking around online, most places in Australia are quoting a turnaround of 2-3 days as the fastest option. Could it be done faster if one of my other characters is a doctor and has a friend who works at a (private, if necessary) lab? If so, what kind of a lab would it be? Assume the characters have enough money and motivation to pay whatever's necessary.

One other question: The potential father is in fact the boy's uncle. Would the probability of paternity still be 0%? Or would the test show that there's a familial relationship?

Many thanks!

04-19-2016, 12:36 PM
There's same-day service in the US, so you should be able to do it in 24 hours.

I'm not an expert (at all!), but I'm fairly handy with Google. Until an expert turns up, hopefully, this will give you somewhere to start, research-wise.

I think the quickest would probably be Y-DNA analysis, using STR.

My best guesses on timing: The PCR reaction (https://en.wikipedia.org/wiki/Polymerase_chain_reaction) to replicate the genetic material should take around a couple of hours, I believe. Gel Electrophoresis (https://en.wikipedia.org/wiki/Gel_electrophoresis), somewhere around an hour.

Info on STR, here (http://www.biotechniques.com/multimedia/archive/00003/BTN_A_000112582_O_3268a.pdf). Standard Kit and instructions to do the test, here (https://www3.appliedbiosystems.com/cms/groups/applied_markets_support/documents/generaldocuments/cms_041201.pdf). The Lab's going to need a thermal cycler, a genetic analyzer and several chemicals (see page 15 of that last link).

As far as I'm aware -- if the man being tested is his uncle, then the result will show with a fairly high degree of confidence that they're related, as the STR markers rarely change from father to son.

04-21-2016, 07:14 PM
On CSI (my main source of knowledge about DNA tests, so take this with a huge grain of salt), DNA can show if someone is a "first degree relative" (50% shared genes: parent, offspring, full sibling) or a "second degree relative" (25% shared genes: grandparent, grandchild, aunt, uncle, niece, nephew, half sibling).

Dennis E. Taylor
04-21-2016, 09:00 PM
If you need it quickly and are concerned about plausibility, just have the protagonist "know someone" who can rush it through on the QT.

04-22-2016, 08:03 AM
The actual test (DNA extraction from the cheek cells, PCR, and a gel to look at it) would take a few couple hours at most, so any extra time is going to depend on how much the company can "rush job" it.

04-22-2016, 02:20 PM
Not specific to DNA tests, but as a physician I can tell you that the turn around times that are quoted by labs are to allow for having to redo the test if there's a software or hardware glitch (those are obvious) or a wetware glitch (user error, mislabeled tubes etc) and also to allow time for the physician who ordered the test to have time to review the labs, so generally there's about 3 days tacked on at the end for quoted turn around. So, yes, knowing someone in the lab will make a difference assuming that someone isn't risking their job by telling your character.

05-04-2016, 08:10 AM
Turn around time in my lab for something like this would be considered non-stat so would be about one to two weeks. Paternity labs advertise 2 days turnaround time.
If you knew a friend that could do it for you after hours, say in a research type lab it would be about 3-4 hours, depending on the technique used.
Type of labs include research labs, paternity labs, medical labs and HLA labs (think kidney and bone marrow transplants) can do it but in a pinch, but it is out of vogue because it is less accurate.
I believe the most common type of test used for accuracy is the STR (short Tandem Repeat)
There is a probable chance that an uncle would show as a relation but 0.0000something% chance of being the parent.
My creds are I used to work in an HLA lab.
Hope this helps!

05-04-2016, 08:16 AM
Oh, forgot to add that in an old-school HLA lab a Terasaki tray can be done in under an hour.