To get a paternity test in Illinois, you have three practical routes: buy an at-home DNA kit for personal knowledge, schedule a legal test at an accredited lab, or get one ordered through the Illinois Department of Healthcare and Family Services (HFS) or a court. Which route fits depends on whether you just want to know or whether you need results a judge will accept.
At-Home Kits vs. Legal Tests
The first thing to sort out is what you plan to do with the result. At-home “peace of mind” kits let you collect cheek swabs yourself and mail them to a lab. They run roughly $80 to $200. Because no one verifies who provided the samples, these results are not admissible in court.
A legal paternity test costs more, typically $300 to $500, and looks different from the moment you walk in. A trained collector swabs each person’s cheek under supervised conditions, checks identification, and documents a chain of custody so the results hold up as evidence. If there’s any chance you’ll use the results for child support, custody, benefits, or a birth certificate correction, pay for the legal version.
Either way, use a lab accredited by a nationally recognized body. Illinois courts generally require accreditation from the Association for the Advancement of Blood and Biotherapies (AABB), which has set relationship-testing standards since 1982.1Association for the Advancement of Blood and Biotherapies. AABB-Accredited Relationship Testing Facilities Results typically come back within a few business days after the lab has all samples.
Getting a Test Through HFS
If you have a child support case open with HFS and paternity hasn’t been settled, the agency can order genetic testing without going to court. After you meet with a child support specialist, HFS issues an administrative order for testing, which the alleged father receives in person or by certified mail.
Before the test, HFS asks the alleged father to sign an “Agreement to be Bound,” committing him to accept the results. A confirming test leads HFS to enter an administrative parentage order. An alleged father who wants to contest the outcome can ask that the case move to court. Skipping the testing appointment entirely lets HFS declare paternity by default.2Illinois Department of Healthcare and Family Services. Parentage Information You Should Know
Getting a Court-Ordered Test
When there’s no HFS case and the parents don’t agree, you can ask a judge to order testing as part of a parentage petition. Any interested party can file, including either parent, the child, a person whose parentage is to be determined, or a government agency. The petition goes in the circuit court of the county where the child lives.3Illinois General Assembly. Illinois Code 750 ILCS 46/401 – Proceeding Authorized
You’ll need to serve the other parent with the petition and a summons. The summons must include a plain-language warning that failing to appear could result in a support obligation lasting until the child turns 18, plus liability for pregnancy and delivery costs.4Illinois General Assembly. Illinois Code 750 ILCS 46/606 – Summons
Once the judge orders testing, the mother, child, and alleged father submit samples at an accredited lab under supervised collection. Refusing the test doesn’t end the case. A court can resolve the parentage question against the person who refuses, meaning an alleged father who dodges court-ordered testing may be declared the legal father by default, with the financial obligations that follow.
Who Pays for a Court-Ordered Test
The party requesting genetic testing pays upfront, though the judge has discretion to split the cost. If the person seeking to establish paternity can’t afford it and a public agency represents them, the agency covers the expense. Where no agency is involved and the requesting party or the alleged father is found indigent, the county where the case was filed pays. After the case wraps up, the court can reassign the testing cost as part of the final judgment.5Illinois General Assembly. Illinois Code 750 ILCS 46/405 – Cost of Genetic Testing
Court filing fees vary by county. If you can’t afford them, Illinois courts offer a fee waiver application for civil cases; you’ll need to show financial hardship, but approval eliminates the upfront filing cost.
Skipping the Test With a Voluntary Acknowledgment
If both parents agree the alleged father is the biological father, you don’t need a DNA test at all. Both parents sign a Voluntary Acknowledgment of Parentage (VAP), and once it’s filed with HFS, the father’s name goes on the birth certificate without a hearing or child support case.6Illinois Department of Healthcare and Family Services. Voluntary Acknowledgment of Parentage Frequently Asked Questions
The easiest time to sign is at the hospital right after birth, where staff witness the signatures and submit them electronically. If you miss that window, each parent can sign later in front of a witness who is at least 18 and not named on the form, then mail the form to HFS. The form asks for each signer’s Social Security or tax identification number, but leaving those blank doesn’t invalidate the acknowledgment.7Illinois General Assembly. Illinois Code 750 ILCS 46/301 – Voluntary Acknowledgment of Parentage
Testing Before the Baby Is Born
You don’t have to wait until birth. Non-invasive prenatal paternity testing (NIPP) can identify the biological father as early as seven weeks into pregnancy. The procedure requires a blood draw from the mother and a cheek swab from the alleged father. Fetal DNA circulating in the mother’s blood is compared against the father’s sample, and the test is over 99.9% accurate.
Prenatal tests done through an AABB-accredited lab with proper chain-of-custody procedures can be used as legal evidence. Confirm gestational age with an ultrasound before testing, since going too early reduces reliability. Expect to pay $1,000 or more; the lab work is more complex than a standard postnatal test.
Reading the Results
A paternity report comes back with one of two conclusions. An “exclusion” means the tested man is not the biological father; the DNA comparison found enough mismatches to rule him out, showing a 0% probability of paternity.
A “not excluded” result means the tested man is considered the biological father. The report includes a probability of paternity, which in credible tests nearly always exceeds 99.9%. It also gives a Combined Paternity Index (CPI), showing how many times more likely it is that the tested man is the father than a random unrelated person. You won’t see 100% on any report, because statistical models account for theoretical uncertainty, but a probability of 99% or higher creates a strong presumption of parentage for legal purposes.
In rare cases, genetic mutations can produce a mismatch at one or two markers even when the tested man is the real father. Accredited labs run additional testing when they see this pattern rather than issuing a false exclusion. If a result looks inconsistent with what you expected, ask whether mutation analysis was performed.
What a Confirmed Result Unlocks
Establishing paternity has real consequences for the child and both parents. A child with legally established paternity can receive Social Security survivor or disability benefits if the father dies or becomes disabled. The Social Security Administration determines eligibility based on whether the child could inherit under state law, whether the father acknowledged the child in writing, or whether a court established parentage. For a deceased father, the acknowledgment or court order generally must be in place before his death, though SSA won’t enforce state deadlines requiring paternity actions within a specific time after the father’s death or the child’s birth.8Social Security Administration. 20 CFR 404.355 – Who Is the Insured’s Natural Child
If the father is a military veteran, the child may qualify as a dependent for VA disability, pension, or survivor benefits, added through VA Form 21-686c.9U.S. Department of Veterans Affairs. Manage Dependents for Disability, Pension, or DIC Benefits The child also gains inheritance rights and access to the father’s medical history, which can matter for identifying hereditary conditions.
For the parents, a legal paternity determination is the doorway to custody, visitation, and child support. The father gains standing to seek parenting time. The mother, or the state, can enforce a support obligation. Without it, a father has no enforceable right to see his child, and a mother has no mechanism to compel financial support.