How Long Does a DNA Test Take?

Michelle Wilson - February 7, 2024

A DNA test determines parental lineage, ancestry, and other genetic factors that influence our makeup. These tests are available through a medical professional or as a direct-to-consumer product. The three most common types of DNA tests are autosomal, mitochondrial, and Y-DNA. Turnaround times for DNA testing will vary according to the requested test. Most tests are finalized within two to five days, although some genetic testing can take several weeks.

What is DNA?

DNA or deoxyribonucleic acid is the molecule containing the unique genetic code of an individual. This code acts as an instruction manual for proteins within our body, telling them how to help the body thrive. Information within DNA is hereditary, passing from parent to child in a unique sequence.

How Does Someone Perform a DNA Test?

Anyone wanting a DNA test can start the process with a medical professional. Genetic testing, including DNA tests, uses saliva, skin, amniotic fluid, or hair to determine the results. Most commonly, buccal smears collect cells within a person’s cheek to collect a sample. Samples are sent to the lab, where specialized technicians will review proteins, chromosomes, or DNA changes. After finalization, a report is mailed to the individual, counselor, or doctor.

What is Genetic Ancestry Testing?

Genetic ancestry testing offers interested individuals the ability to learn about relatives through genetic makeup. DNA variations provide clues to an individual’s ancestors and the relationships held between families. Some patterns of genetic variation are common within particular backgrounds. The more closely related two people are, the more patterns of expression and variation they will share.

What is Autosomal DNA Testing?

Autosomal DNA testing will evaluate the DNA from parents, including the 22 pairs of chromosomes that comprise an individual’s autosomes. The details within the chromosomes will help identify recent and distant relatives, including where ancestors lived 500 to 1000 years ago. Autosomal DNA testing offers far more information than the other types of DNA testing, as it reveals more about ethnicity and ancestry.

What is Mitochondrial DNA Testing?

Mitochondrial DNA testing traces an individual’s genetic makeup through the maternal ancestry. This testing method will use the individual’s mitochondria to assess the genetic coding. Mitochondria is the powerhouse of a cell, which passes exclusively from the mother’s genetic makeup. This testing method is limited as it only traces the mother’s lineage. It can trace back thousands of years but only offers evidence that someone is related to an individual.

What is Y-DNA Testing?

Individuals with a Y chromosome use Y-DNA testing to determine patrilineal ancestry. This method is standard for infant paternity tests, using the biological male. The Y chromosome passes through the person’s father, inheriting it throughout the generations. This testing offers support that a genetic match exists. This method of DNA testing can trace genetics back thousands of years but can only determine the genetic male portion of ancestry.

Can DNA Tests Determine Paternity During Pregnancy?

There are currently three ways to determine paternity before a baby is born. These tests remain as accurate as DNA samples after birth. These three methods include:

Non-Invasive Prenatal Paternity Test (NIPP)

This test will use fetal DNA found within a pregnant woman’s blood to determine DNA during the first trimester. Lab specialists will compare the fetal DNA with the potential father’s cell sample.

Chorionic Villus Sampling (CVS)

Healthcare providers will take a small sample of tissue from the placenta while the fetus is still inside the mother. The process occurs through the mother’s cervix or abdomen, typically 10 to 13 weeks after a woman’s last menstrual period. The lab then compares the sample with the mother and father’s DNA to determine paternity. This method of testing does pose a slight risk of pregnancy loss or miscarriage.

Amniocentesis

An amniocentesis is an invasive procedure that involves a healthcare provider drawing out a small amount of amniotic fluid. The test inserts a needle into the mother’s abdomen and requires the use of ultrasound equipment to monitor the fetus and its positioning. The lab then compares fluid samples with DNA samples from the mother and father. An amniocentesis will typically occur between the 15^th and 20^th week of pregnancy. This method of DNA testing poses a higher risk of premature labor and miscarriage.

How Accurate is Paternity Testing?

DNA tests may differ in testing methods, but most will use saliva samples for paternity results. Paternity tests help assess a person’s probability of fathering a child. These tests are highly accurate, with a 99.99% accuracy rate. For accurate results, individuals should use medical professionals to administer the test and determine the results.

After the paternity test runs, a report will include a “probability of parentage.” The results may indicate a 0% probability, indicating the alleged individual is not the child’s biological parent. Alternatively, the results may indicate 99.99%, confirming the biological relation.

What is Direct-to-Consumer Genetic Testing?

Direct-to-consumer testing offers consumers detailed information about their health, ancestry, and traits. The results aren’t always clear cut, suggesting the individual may have a higher probability of developing specific characteristics or conditions, but they aren’t guaranteed.

As such, many direct-to-consumer genetic tests will indicate the tests serve as information, education, and research only.

DNA Testing for Health and Disease Risk

This genetic test will examine specific information that increases the chance of developing certain diseases. It also evaluates the probability of having particular traits. These tests offer users insight into the possibility of reacting to certain medications and other medical factors.

A health and disease assessment doesn’t offer individuals a yes or no answer. These tests fail to consider environmental factors, lifestyle choices, or other aspects that may influence the probability.

DNA Testing for Genealogy or Ancestry

These tests will offer major geographic areas relating to family origins. Results use genetic variations commonly found within some regions to determine origins. Occasionally, these tests will reveal differences between genetic locations and the known family history. As everyone holds an individual genetic makeup, these results may vary slightly among siblings or immediate family.

DNA Testing for Kinship

A DNA test will offer information about individuals most likely related to a person according to their genetic makeup. These individuals must undergo testing, and the predictions are based on genetic similarities among DNA sequences. Tests can uncover biological relationships, including parents, grandparents, aunts, uncles, or cousins.

Conclusion

DNA testing serves several purposes within the medical community and as a consumer product. Individuals ordering a DNA test should understand the limitations of the process, particularly as it relates to genetics or ancestry. While paternity tests are 99.99% accurate, other results will use statistics and sequencing to determine the results, which may hold slight errors. Most DNA test results return within two to five business days, although some genetic testing can take several weeks to review.