Whether or not saliva can replace blood for DNA collection in analysis was a huge question, back in 2012. However, nothing has really changed. At DNA Testing Atlanta, we usually get asked whether blood or saliva is more accurate for our tests.
We know blood collection will always be a necessary practice in healthcare. Our blood contains some biomarkers that may not be present in saliva: proteins, antibodies and metabolites. However, when the purpose of collection is strictly for genomic DNA analysis, saliva makes a lot of sense.
It’s saliva a viable option for DNA testing in Atlanta?
Saliva (your spit) is a fluid from inside your body just like blood. Your body creates your spit just as your body creates your blood. Ergo, your saliva is unique to you just like your blood is unique to you.
Saliva is also a faster resource to use in DNA tests. When we perform a DNA test with blood samples, our technicians at DNA Testing Atlanta verify the collector tube, do the procedure to get the blood by your arm and get the samples in order to perform an affordable blood DNA test.
With a saliva sample, our technicians just open up a sterile swab, rub it inside your cheek, and it’s all over. It also take them less time to break down the DNA inside the saliva than it does with the blood; making your results available at a fast rate.
When we take the sample form your mouth, we also grab some cells from the mucosal lining of the cheek with that tiny swab. That it is what provides the DNA needed to perform the test. It is so simple and quick that you do not even feel it.
DNA saliva quality in Atlanta tests
Saliva DNA must perform equivalently in downstream applications to that of blood to merit a change from blood. This means the quality and quantity of DNA extracted from saliva must meet the standards set and achieve by blood.
Up to 74% of the DNA in your saliva comes from white blood cells, the same source of DNA as in blood. However, the major issue with saliva DNA arises when naturally degrading enzymes and bacteria within the sample attack DNA integrity and decrease quality very quickly.
In order to maintain the integrity of DNA in saliva, DNA Testing San Jose’s licensed staff uses the Oragene self-collections kits. Those kits contents reagents that preserves the high molecular weight DNA by inhibiting degradation and preventing bacterial contamination.
Multiple studies confirms that the DNA extracted from Oragene/saliva samples, results in DNA of the highest integrity, performing equivalently to blood for applications such as PCR, SNP, genotyping, microarrays and next-generation sequencing.
5 facts you probably don’t know about saliva
1. DNA in saliva derived from both buccal epithelial cells and white blood cells.
It might surprise you to know that much confusion surrounds the real source of genomic DNA in saliva. Surprisingly, most people assume the source of DNA in saliva is strictly buccal epithelial cells. However, studies show that up to 74% of the DNA in saliva comes from white blood cells, which are an excellent source of large amounts of high quality genomic. This means, saliva can be considered equivalent to blood for genetic applications.
2. The vast majority of DNA from saliva is of human origin.
While most scientists prefer large amounts of DNA, technological advances in downstream platforms now enable testing on even small amounts of DNA with the caveat that the DNA is of sufficient quality. As stated previously, the majority of DNA in saliva comes from white blood cells. However, human saliva also contains bacteria.
When extracting DNA from saliva, bacterial DNA is recovered along with the human DNA. When compared to other oral sampling methods, such as buccal swabs or mouthwash, a 2mL saliva sample collected with Oragene yields approximately 11% bacterial DNA, substantially lower than mouthwash at 66% and cytobrushes at over 88% bacterial DNA.
3. Saliva can reliably replace blood for DNA analysis.
Blood collection is considered the golden standard for DNA quality and it is an established practice across hospitals, clinics, and labs worldwide. However, many people don’t know that replacing blood with saliva is a proven option for genomic DNA analysis.
Saliva collection kits (Oragene) are designed to stabilize high molecular weight DNA by inhibiting degradation and preventing bacterial growth. Multiple studies confirms that DNA extracted from saliva samples, results in DNA of the highest integrity. Wich means that the results could be perform equivalently to blood for the most demanding applications.
4. Collecting DNA from saliva is less expensive than DNA from blood.
The price associated with blood collection may be perceived to be free for many institutions that have established labs/service centers; however, there are real costs to sample collection even within these environments. Phlebotomists, medical supplies and shipping requirements (dry ice, containers, and overnight delivery) add an estimated $40 per sample, not including freezer storage.
DNA from saliva, in comparison, comes in a variety of formats with differing yield and stability capabilities which cost between 48% – 80% less.
Overall, saliva is less expensive than blood for DNA collection when factoring in all costs associated with the sample collection procedure.
5. DNA saliva sample collection methods are NOT all equal.
There are 3 methods for collecting oral DNA samples – dry, wet and non-invasive procedures.
Dry procedures require the donor to insert a cytobrush, buccal swab or other collection device into the mouth. The tissue is scraped from the gum and cheek surfaces. These methods collect primarily buccal cells and a high proportion of bacteria which stick to the gumline.
However, DNA samples collected from saliva where the donor spits into a collection device are quite different and offer higher yields than other oral DNA sample collection methods.
All the DNA saliva methods are different. You can be confident when choosing an option like Oragene, which optimizes both quality and quantity of DNA.
As leaders in costumer services, DNA Testing Atlanta we want to make the DNA testing process as simple as we can. We want to give you up-to-date information about DNA tests.
Blood seems like the best route and we understand when our patients prefer a blood test for their DNA needs. It is good to note that perform a blood test does not make more accurate the results. In fact, could be a more expensive, more invasive and more frightening for the child. However, we are here to assists you and support you on whether you decide.
We hope this helps clear up much of the misinformation that continues to circulate about DNA from saliva. If you haven’t chosen DNA from saliva in the past, you should now feel confident in making that choice for any DNA analysis.
Thousands of researchers and clinicians around the world are already working with saliva due to its high quality performance coupled with quick and easy collection and efficient transport.