How Does DNA Testing Work? (A Quick Guide)
Updated on March 18, 2024
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DNA Testing
How Does DNA Testing Work? (A Quick Guide)

DNA or genetic testing involves several steps. It starts with getting DNA samples, usually via saliva or blood. The sample is then sent to a lab for analysis. Results are sent back, and, with the help of a genetic counselor, the results can be better interpreted so you can understand any steps you have to take next based on your results.1

If you plan on getting a DNA test, read this complete guide.

How Does DNA Testing Work? (A Quick Guide) 3

How to Take a DNA Test?

Depending on the information you’re after, you can take a DNA test at a laboratory, in your doctor’s office, or at home. 

A medical provider may arrange the details of your genetic testing. You may also opt for an at-home test kit.

At-Home DNA Testing

The instructions for at-home DNA test kits may vary for each provider. But generally, this is how the procedure goes.

  1. Order DNA testing kits online — Most companies where you can purchase DNA testing kits will ask you to sign up to an online portal with a dashboard that will keep your results and raw DNA data.
  2. Secure your DNA sample — The company’s method of DNA collection varies, but most at-home DNA test kits require swabbing your inner cheek or spitting into a tube.
  3. Mail your DNA samples back to the lab — Use the prepaid return label in your test kit. Most companies include this with your test kit.
  4. Receive your test results — Your DNA sample will be tested across the company’s database, giving you information depending on your choice of test kit type.

Your chosen provider will also determine the turnaround time for your DNA results. However, results are typically available within three to five days.

Professional DNA Testing

Once you’ve decided on genetic testing, your healthcare provider may set up testing for you. Genetic testing is often included in a genetic consultation. 

Professional DNA tests analyze the same information in your DNA sample and provide results that are admissible in court.2

You can use them to resolve legal issues, like paternity, to determine the biological father, to address child support disputes, etc.

You must go to a doctor’s office, lab, or medical setting for professional genetic testing. The medical experts will collect any of the following acceptable sources of DNA samples:

  • Blood
  • Hair
  • Skin
  • Amniotic fluid for pregnant women
  • Saliva
  • Inside the cheeks

The person who collected your sample will send it to a lab. Lab technicians look for specific chromosome, DNA, or protein changes or patterns and note any that are out of the ordinary.

The lab sends written test results to your doctor or genetic counselor. They can also send the reports directly to you if you request them. 

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Who Should Undergo A DNA Test?

Genetic testing is relatively safe. It’s beneficial for anyone who is:

  • Trying to determine their biological father
  • Interested in their family history and heritage
  • Looking for missing family members 
  • Trying to prove familial relations
  • Curious about their health
  • Predisposed to genetic conditions

But before getting a DNA test, it’s essential to know the pros and cons of genetic testing and what the test could show. 

Talk to a genetic counselor for proper guidance in DNA testing, especially for health purposes.

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When Your Doctor May Recommend Genetic Testing

If you’re expecting or a parent of a young child, your doctor may recommend genetic testing based on your family history. 

Gene mutations can cause a wide range of health problems, especially in children, such as:

  • Developmental issues
  • Delays of motor, speech, or cognitive function
  • Birth defects in one or multiple organs
  • Hormone problems
  • Problems with vision or hearing
  • Movement disorders
  • Seizures
  • Chronic behavior problems
  • Immune disorders resulting in frequent illness
  • Heart rhythm problems
  • Stagnant growth

If your child has symptoms of a condition linked to a genetic disorder, your child’s doctor may suggest genetic testing. They need to confirm a diagnosis to start a treatment plan.

What Information Can You Learn From Your At-home DNA Test Results?

Your test results will give you information based on your chosen testing type. For example, most at-home DNA test kits assess your sample for genetic ancestry to know your biological father, mother, and other potential relatives.

Companies like Ancestry and 23andMe claim they can trace your family’s origin from your paternal and maternal lines. 

Other information you can learn from genetic testing include:

  • Risks of developing a genetic condition
  • Genetic diseases or chromosomal problems 
  • Carrier status or your chances of carrying a copy of the mutated gene
  • How your DNA influences your appearances or traits

How Accurate Are At-Home DNA Test Results?

Most DNA test results are accurate. Genetic testing labs follow CLIA regulations—the standard quality framework across clinical laboratory testing. CLIA ensures that test results remain accurate and reliable.5

What Should You Do After Getting Your At-home DNA Test Results?

Once you’ve received your test results, you can do a few things with them:

Protect Your Raw DNA Data

Your DNA is your blueprint, and you should do everything you can to protect it. Almost every provider lets you download your raw DNA data. Once you’ve done this, consider deleting it from their system.

Review Your Shared Genetic Matches

Your DNA test results can be used to confirm suspected relations or explore your family tree. It’s rare, but DNA testing could reveal long-lost relatives or notable ancestors.

Seek Help From a Health Professional

At-home testing is not meant to be diagnostic. If you learn about a health concern, don’t panic.

Share your results with your doctor and discuss your options. It would help if you didn’t use at-home DNA testing alone to make important health decisions.

It’s also important to remember that DNA tests like 23andMe don’t consider your lifestyle. You might already be managing your genetic risk for certain diseases, so there’s no need to worry.

View your DNA test results as a starting point for improving things, but don’t see it as the end-all-be-all for informing your decisions.

What Is DNA?

Deoxyribonucleic acid, or DNA, is a long molecule with unique genetic codes. It has instructions essential for development and functions.3

For instance, it contains different codes for making all the proteins in your body. 

All cells in your body have DNA—mostly found in the nucleus. They’re called nuclear DNA. However, your cells’ mitochondria also hold bits of DNA. This is called mitochondrial DNA.

The DNA molecule is encased into thread-like structures called chromosomes. Chromosomes carry DNA in your cells. Each cell has 23 pairs of chromosomes, or 46 in total.4

Half of your chromosomes come from your mother’s genetic material. The remaining half is from your father.

DNA Structure

A nucleotide is one of the building blocks of DNA. A DNA molecule consists of two long polynucleotide chains totaling four nucleotides.5

Each nucleotide has three parts: a nitrogen base, a molecule of sugar, and phosphate groups.5

The sugar molecule found in DNA is called deoxyribose. It alternates with the phosphate group to form the backbone of the DNA strand.5

Each deoxyribose is attached to a nitrogen base. DNA has four different nitrogen bases:

  • Adenine (A)
  • Cytosine (C)
  • Guanine (G)
  • Thymine (T)

DNA has two strands that form a 3D shape called a double helix. On a closer look, the strands look like spiral, twisting ladders. The base pairs are the rung, while the sugar-phosphate backbone is the legs.

How Does DNA Testing Work? (A Quick Guide) 4

DNA can make copies of itself. Each DNA strand in the double helix becomes a pattern for replicating the bases’ sequence.

Sometimes, errors happen in DNA replication while making new cells or cell division. It can lead to genetic mutations.6

Genetic mutations are any changes that occur to your DNA sequence. They can help you better adapt to your environment or cause genetic conditions like cancer.7

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Updated on March 18, 2024
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7 sources cited
Updated on March 18, 2024
  1. Genetic Testing.” Centers for Disease Control and Prevention.

  2. Use of DNA Information in the Legal System.” National Library of Medicine.

  3. Deoxyribonucleic Acid (DNA) Fact Sheet.” National Human Genome Research Institute.

  4. Chromosomes Fact Sheet.” National Human Genome Research Institute.

  5. Nucleotide.” National Human Genome Research Institute.

  6. Genetic Mutation.” Nature Education.

  7. Genomes.” National Library of Medicine.

Dr. Dhingra
Dr. Harshi Dhingra
Medical Reviewer
Dr Harshi Dhingra is a licensed medical doctor with a specialization in Pathology. Dr. Dhingra has of over a decade in diagnostic, clinical, research and teaching work, including managing all sections of Pathology laboratory including histopathology, cytology, hematology and clinical Pathology.
Kelly Brown
Kelly Brown
Content Contributor
Kelly has experience working with clients in a variety of industries, including legal, medical, marketing, and travel. Her goal is to share important information that people can use to make decisions about their health and the health of their loved ones. From choosing the best treatment programs to improving dental and vision health to finding the best method for helping anyone who is struggling with health issues, she hopes to share what she learns through informative content.