How Long Does DNA Last On A Swab?

How long can DNA samples last? And how to properly collect them

Before we look at how long the DNA samples can last, let’s look at a little background regarding the life of DNA. DNA can last for many years, depending on the storage conditions and the storage media. Researchers have recently estimated that DNA has a half-life of 521 years, meaning that this is the duration it can take for the DNA molecule to be broken.

When put under the ideal conditions, the DNA can last for approximately 6.8 million years. After this period, all the bonds would be broken down. However, it is difficult to read the DNA after a period of 1.5 million years, according to the recent findings by researchers. The oldest known DNA to be ever recorded was found in the Greenland ice and is estimated to be in the range of 450 000 and 800 000 years of age.

So, how long can DNA samples last? Well, if you collect your DNA samples correctly using a swab it can last for up to 6 months. The duration is not limited to 6 months because it can be extended to a year.

However, the right stabilizing fluid ought to be included. But there is no guarantee for the exact duration that a DNA sample will last because different samples present unique features. As such, it is recommended that you test the samples at the nearest convenience following the collection.

Buccal Cheek Swabs for DNA Collection

The first thing a DNA sample collector will do at the time of your sample collection appointment is, complete your chain of custody form. Below is the name of the fields, you can expect to see on your chain of custody form.

• client’s name
• Birthdate
• Address client’s address
• Date and time of collection
• The initials of the collector

The procedure

1. Ask the patient to rinse their mouth with clean water before you start collecting the samples.
2. Wear the gloves throughout the rest of the procedure
3. Take the swab from its packaging without allowing it to touch any surface or object.
4. Hold the swab between the thumb and the forefinger and insert the brush into one side of your mouth between the upper gum and the inside of the cheek. Twirl the cheek brush against the inner cheek while pressing firmly.
5. Use an upward and a downward motion in the front and backward direction and then back to the front. Time each collection to be about 30 seconds for every swab. Sample collection is recommended at the points bearing the maximum mucosal areas.
6. Do not saturate the swabs with an unnecessary amount of saliva, although you can moisten an area with saline using a swab is allowed.
7. Remove the swab out of the patient’s mouth and leave it to air dry by placing it on a sterile surface for the next five minutes.
8. Put the swab back to its original container and seal the lid.
9. Repeat this collection procedure about for more times to give you five samples on average.
10. Place the swabs into the labeled envelope.
11. Forward the samples for processing to the laboratory. Please note, the average turnaround for paternity testing results to be completed in 2 to 3 business days.

How long can I leave the swabs out before they become unusable?

Leaving the swabs out for more than 15 minutes is dangerous because it can render them unusable. As such, it is recommended that you put them back in their protective sleeves soon after you notice that they have started air-drying, usually in about five minutes.

However, you can still subject them to extended drying time if necessary. But you’ll increase the possibility of contaminating the swabs by when you leave them exposed for a long duration, making them unusable. Importantly, avoid resealing the sleeves because doing so can increase the possibility of bacterial growth.

How long does saliva DNA last on an object?

The length of time DNA lasts in your mouth depends on several factors, including:

• The type of DNA: Studies have shown that male DNA, specifically from the Y chromosome, can persist in female saliva for at least an hour after a passionate kiss . This is because the Y chromosome is present in much higher quantities than other chromosomes in male cells.
• The amount of DNA transferred: The more DNA transferred, the longer it is likely to last.
• The environment in your mouth: Factors like eating, drinking, and brushing your teeth can all break down DNA.

Overall, while DNA can be detectable in your mouth for a short period of time, it is constantly being broken down and eventually won’t be recoverable.

How long does saliva DNA last outside the body?

The lifespan of salivary DNA outside the body heavily depends on various environmental factors:

• Temperature:
• Warm temperatures: Accelerate the breakdown of DNA.
• Cold temperatures: Can significantly preserve DNA, even for years.
• Sunlight: Ultraviolet radiation directly damages DNA, leading to faster degradation.
• Humidity: High humidity promotes microbial growth, which can break down DNA.
• Surface:
• Porous surfaces: Like fabric, absorb and retain saliva, potentially preserving DNA for longer periods.
• Non-porous surfaces: Like glass or metal, allow drying, which accelerates DNA degradation.

Therefore, it’s impossible to provide a single, definitive answer about how long salivary DNA lasts outside the body. However, here’s a general time-frame based on different conditions:

• Favorable conditions (cold, dry, dark): Weeks to months.
• Room temperature with moderate humidity: Days to weeks.
• Direct sunlight and hot temperatures: Hours to days.

Important to remember: These are just estimates, and the actual time-frame can vary significantly depending on the specific circumstances.

Conclusion:

In summary, we have addressed several key aspects related to DNA collection and testing using cheek swabs:

• DNA can persist on a swab for up to 15 minutes before drying out. Leaving swabs exposed longer than this can lead to contamination or make them unusable.
• Under proper storage conditions, DNA on a swab can last for 6 months to 1 year. The right stabilizing fluid is important for extending duration.
• The cheek swab collection procedure involves using sterile technique to rub the inside of the cheek to collect saliva and epithelial cells. Multiple swabs are taken to ensure sufficient sample.
• Swabs should be air dried for 5 minutes before sealing to avoid bacterial growth. They are then sent to a lab for analysis.
• Test results are usually available within 2-3 business days. The DNA is compared to reference samples to determine relationships or identify individuals.
• Both swab and blood collection methods can effectively provide DNA for testing purposes. Following the enclosed instructions carefully is important for accurate results.

In closing, cheek swab kits allow easy self-collection of DNA samples which can then be analyzed to accomplish various genetic testing goals when done properly. Understanding how long DNA lasts, the collection process, and how the testing is performed helps ensure reliable outcome.

If you are in need of DNA paternity testing services. Call 877-680-5800 to schedule an appointment today.