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The journal · Newborn basics

The Newborn Heel Prick: What the Newborn Screening Test Looks For

October 14, 2026 · 13 min read · 6 sources cited

In short

Somewhere in your baby's first day or two, a nurse pricks their heel and collects a few drops of blood onto a filter-paper card. That is newborn screening, and it checks for dozens of rare but treatable conditions before any symptom shows up. The timing is deliberate: 24 to 48 hours old, after your baby has fed. Results usually reach your provider by five to seven days. An out-of-range result is not a diagnosis — it means one more test, and the follow-up is the part that matters.

Somewhere in the first day or two of your baby's life, someone comes in with a small card, a tiny lancet, and an apologetic look. They prick your newborn's heel, press a few drops of blood onto a row of circles on filter paper, and take the card away. The whole thing lasts about a minute. Your baby will probably cry. And if nobody explains what just happened, it lands as one more unexplained thing in a hospital stay already full of them.

That minute is the newborn screening blood test — the heel prick, the heel stick, the blood spot card, depending on who is talking. It is checking for dozens of rare conditions that are very treatable when caught early and much harder to treat once symptoms appear. Here is what it is, when it happens, why the timing is so specific, and what to do if a result comes back out of range — with every claim traced to the source it came from.

01Newborn screening is not one test but three

The heel prick is the part parents remember, but it is one leg of a three-part screen. The AAP describes newborn screening as a blood test, a hearing test, and a heart screening. MedlinePlus, the NIH's consumer health library, lists the same three.

The reason all three exist comes down to timing. MedlinePlus puts the case plainly: "If not treated, some of these conditions can cause lifelong health problems. Others can cause early death. With early diagnosis, treatment can begin right away, before serious problems can occur or become permanent." The CDC sums up the whole program in one line — "newborn screening identifies conditions that can affect a child's long-term health or survival."

02When it happens, and why the window is so narrow

The AAP says newborn screening tests "usually are performed when babies are one to two days old." Baby's First Test, the newborn screening clearinghouse funded through the federal government, is more precise: "the blood test is generally performed when a baby is 24 to 48 hours old." The Cleveland Clinic gives the same 24-to-48-hour window.

That is not a scheduling convenience. Baby's First Test explains both edges of the window: a sample drawn before 24 hours can miss certain conditions, and waiting past 48 hours risks delaying treatment for a baby who needs it. Some of the markers the lab is looking for simply have not had time to build up in the first few hours of life.

There is one more piece of the timing that parents rarely hear in advance. "Ideally your infant should be fed prior to the test," Dr. Phelps tells the Cleveland Clinic. Baby's First Test gives the reason from the other direction: one of the ordinary, harmless explanations for an out-of-range result is that the sample was collected too early or the baby had not fed enough beforehand. So a feed before the heel prick is not just comfort — it makes the result cleaner.

03What the heel prick is actually looking for

There is no single national list, which is why two honest sources can give you two different numbers. MedlinePlus says "all states test for at least 30 of these conditions." The AAP is more specific: most states screen for "at least 31 of the 35 conditions recommended by the Advisory Committee on Heritable Disorders in Newborns and Children," the federal advisory committee that maintains the recommended panel. Your state's exact list is set by your state.

The AAP groups what is being checked into a handful of systems: hearing, heart function, metabolism, hormones, and hemoglobin. In practice, the named conditions you are most likely to hear about include these, drawn from the Cleveland Clinic and MedlinePlus.

What those conditions have in common is the whole argument for the test. "Knowing whether your baby has one of these conditions before symptoms appear can make a huge difference," Dr. Phelps tells the Cleveland Clinic, and "early treatment, which can sometimes involve something as simple as a change in diet, can prevent how the disease affects your child." A healthy-looking newborn is exactly who this test is designed for — by the time something is visible, the easy window has often closed.

04What actually happens in the room

It helps to know the sequence, because the whole thing is over before you have worked out what you are watching. The heel prick usually shares the first day or two with a couple of other routine procedures, including the vitamin K shot.

The heel prick, start to finish

  • Your baby gets fed first, if the timing allows — the Cleveland Clinic's advice is that ideally your infant should be fed prior to the test.
  • A card comes out. Baby's First Test describes it in two halves: "one part of this card is the filter paper to collect the baby's blood sample. The other part is for important information for the lab" — your baby's name, weight, time of birth, and your contact details.
  • The heel is pricked. "During the blood test, which is sometimes called a heel stick, the baby's heel will be pricked to collect a small sample of blood" (Baby's First Test). A few drops, pressed into the circles on the filter paper.
  • You can hold your baby while it happens. Both the AAP and Baby's First Test say so directly, and note that babies who are being comforted are less likely to cry.
  • The card dries and travels. "The newborn screening card is then sent to the state laboratory for analysis" (Baby's First Test).
  • The hearing screen and the heart screen happen separately, usually also before you go home (AAP).

You are allowed to hold your baby for this

This is the single most useful thing to know in advance, and nobody tends to offer it. The AAP is explicit: "When parents or health professionals comfort babies during the procedure, they are less likely to cry. You can hold your baby during the procedure and even feed or nurse to keep them comfortable." Baby's First Test says the same. You do not have to hand your newborn over and stand to one side — you can be the one holding them, and feeding them, while it happens.

05When the results come back

The AAP says results are usually ready "by the time your baby is five to seven days old." The Cleveland Clinic says typically within a week. In most cases you will simply never hear anything specific, because a normal screen is not news — which is why it is worth asking your baby's provider at the first visit whether the screen came back clear, rather than assuming silence means it did.

If something does turn up, MedlinePlus describes how you find out: "If a screening shows that your baby might have a condition, the health care provider or the state health department will call you. It is important to follow up quickly. Further testing can verify whether your baby has the condition." That phone call is the reason the lab card asks for your contact details, and the reason it is worth making sure the number on it is one you will actually answer in your first week home.

Out of range is not a diagnosis

This is the part worth reading twice, because an unexpected call about a newborn is terrifying and the wording is easy to misread. The AAP states it outright: "If your baby's test results fall outside the normal range, this doesn't automatically mean they have a health condition." Baby's First Test explains that an out-of-range result means the screen "did show signs that the baby may be at higher risk of having one or more of the conditions" — and that it can also come from the sample being collected too early or the baby not having fed enough beforehand. The next step is a confirmatory test. "If anything shows up as abnormal, the test will be repeated to confirm," Dr. Phelps tells the Cleveland Clinic, and only after that does a specialist "set up a care plan for treatment and close follow up." A screen flags; it does not decide.

06Why some babies get a second heel prick

A second screen a week or two later is often routine rather than a warning sign. The AAP notes that "some states require a second round of tests about one to two weeks after the first tests are taken," and Baby's First Test says the same — "some states require babies to undergo a second newborn screen when they are two weeks old" — to improve accuracy. If you are told to come back for another heel prick, it is worth asking plainly whether it is your state's standard second screen or a follow-up on a specific result, because those two conversations are very different.

07Who checks that the test itself is accurate

A screening test is only as good as the lab running it, and there is an entire program behind that. The CDC runs the Newborn Screening Quality Assurance Program, which "provides quality assurance services to more than 670 newborn screening laboratories around the world" and exists to help those labs "ensure that testing accurately detects disorders, does not delay diagnosis, minimizes false positive reports, and sustains high-quality performance."

The mechanics are oddly satisfying. CDC staff manufacture dried blood spot samples that imitate real newborn specimens carrying real conditions, then send them out — "nearly 1 million dried blood spot reference materials are sent to participating laboratories each year." State laboratories "then use these materials to check their testing methods and results," a process that, in the CDC's words, "helps ensure tests are accurate so that affected babies can be diagnosed and treated as early as possible." In other words, somebody is checking the checkers.

08Is the heel prick required?

Close to it. The AAP says "newborn screening is required by law in all 50 states," while noting that parents may refuse the testing in writing, most often on religious grounds. If you have questions or reservations about any part of it, the useful move is to raise them with your baby's provider before the birth rather than in the hour it is being offered — and if you have not picked that provider yet, our guide to newborn basics covers the first-week decisions in the order they actually arrive.

This is general information, not medical advice

Which conditions your state screens for, how your results are reported, and what any individual result means for your baby are all questions for your own pediatrician, family doctor, or midwife — they have your baby's chart and your state's panel, and you should not have to guess at either. If you get a call about a screening result, call them back the same day. That is exactly what they are there for.

09One minute, dozens of answers

There is not much in new parenthood with a return like this one: one minute, one small card, and a check on dozens of conditions you would otherwise have no way of knowing about until they announced themselves. Knowing the shape of it in advance turns it from an alarming surprise into a thing you can be calm about — you fed your baby, you held them, it took a minute, and the result goes to your provider by the end of the week.

The rest of the first-week learning curve works the same way: almost none of it is hard once somebody tells you what is coming. That is what we built this site to do. Enter your due date and you will get a free, personalized week-by-week plan, with the preparation front-loaded into the middle of pregnancy so the last stretch stays light.

Questions parents actually ask

Why do they prick a newborn's heel?

To collect a few drops of blood for newborn screening. The AAP describes it as drawing a few drops of blood from your baby's heel, which is sent to a lab to check for inherited, metabolic, hormone, and blood conditions. The point is to catch conditions before any symptom shows up, because, as the Cleveland Clinic's Dr. Phelps puts it, knowing before symptoms appear can make a huge difference.

When is the newborn heel prick test done?

Usually when your baby is 24 to 48 hours old, according to Baby's First Test and the Cleveland Clinic. The AAP says one to two days old. The window is deliberate: a sample taken before 24 hours can miss certain conditions, and waiting much past 48 hours can delay treatment for a baby who needs it.

How long do newborn screening results take?

The AAP says results are usually ready by the time your baby is five to seven days old, and the Cleveland Clinic says typically within a week. If something is out of range, MedlinePlus says your health care provider or the state health department will call you, and it is important to follow up quickly.

What does an out-of-range newborn screening result mean?

It means more testing, not a diagnosis. The AAP says results falling outside the normal range do not automatically mean your baby has a health condition. Baby's First Test explains it can also happen if the sample was collected too early or the baby had not fed enough beforehand. The Cleveland Clinic notes the test is repeated to confirm, and only then does a specialist set up a care plan.

How many conditions does newborn screening check for?

It depends on your state. MedlinePlus says all states test for at least 30 conditions. The AAP says most states screen for at least 31 of the 35 conditions recommended by the Advisory Committee on Heritable Disorders in Newborns and Children. Your baby's provider can tell you your state's exact panel.

Can I hold my baby during the heel prick?

Yes. The AAP says you can hold your baby during the procedure and even feed or nurse to keep them comfortable, and that babies who are comforted by parents or health professionals are less likely to cry. Baby's First Test also encourages parents to hold their baby for it.

Why does my baby need a second heel prick?

Often because your state requires it. The AAP says some states require a second round of tests about one to two weeks after the first, and Baby's First Test says some states screen again at two weeks old for accuracy. It is worth asking whether yours is the standard second screen or a follow-up on a specific result.

Sources

  1. HealthyChildren.org (AAP) — Newborn Screening Tests — Newborn screening has three parts — blood test, hearing test, and heart screening by pulse oximetry for critical congenital heart defects; tests usually performed when babies are one to two days old; a few drops of blood drawn from the heel and sent to a lab; results usually ready by five to seven days old; most states screen for at least 31 of the 35 conditions recommended by the Advisory Committee on Heritable Disorders in Newborns and Children; screening covers hearing, heart function, metabolism, hormones, and hemoglobin; babies comforted by parents or health professionals are less likely to cry, and parents can hold, feed, or nurse during the procedure; results outside the normal range do not automatically mean the baby has a condition, and a confirmatory test follows; some states require a second round of tests about one to two weeks later; newborn screening is required by law in all 50 states, with written refusal possible, typically on religious grounds.
  2. Baby's First Test — Newborn Screening Procedures — The blood test is generally performed when a baby is 24 to 48 hours old; samples drawn before 24 hours may miss certain conditions and delays beyond 48 hours risk delaying treatment; the heel is pricked to collect a small sample of blood, sometimes called a heel stick; the card has a filter-paper half for the blood sample and an information half for the baby's name, weight, time of birth, and parental contact details; the card is sent to the state laboratory for analysis; parents can hold their baby during the procedure, which reduces crying; an out-of-range result means the screen showed signs the baby may be at higher risk of one or more conditions, and can also result from early collection or inadequate feeding before the test; some states require a second newborn screen at two weeks old.
  3. MedlinePlus (NIH / National Library of Medicine) — Newborn Screening — Screening tests happen before the newborn leaves the hospital; three types of tests — blood tests on a few drops of blood from pricking the baby's heel, a hearing test measuring response to sound, and a skin test measuring blood oxygen that can indicate a congenital heart defect; all states test for at least 30 inherited conditions; untreated, some conditions cause lifelong health problems and others early death, while early diagnosis allows treatment before problems become permanent; if a screening suggests a condition, the provider or state health department will call and it is important to follow up quickly, with further testing to verify.
  4. Cleveland Clinic — Why Do They Prick Your Newborn Baby's Heel? — Testing occurs 24 to 48 hours after birth and results typically arrive within a week; Dr. Phelps advises that ideally the infant should be fed prior to the test, and that knowing whether a baby has one of these conditions before symptoms appear can make a huge difference; named examples include PKU (about 1 in 10,000 to 15,000 births), primary congenital hypothyroidism, maple syrup urine disease, cystic fibrosis, and sickle cell anemia; the number of conditions varies by state; if anything is abnormal the test is repeated to confirm, after which a specialist sets up a care plan and close follow-up; early treatment can sometimes be as simple as a change in diet.
  5. CDC — Newborn Screening Quality Assurance Program — Newborn screening identifies conditions that can affect a child's long-term health or survival; the program provides quality assurance services to more than 670 newborn screening laboratories around the world; it helps labs ensure testing accurately detects disorders, does not delay diagnosis, minimizes false positive reports, and sustains high-quality performance; it supplies dried blood spot reference materials that mimic newborn specimens, with nearly 1 million sent to participating laboratories each year.
  6. CDC — About Newborn Screening Laboratories — Newborn screening identifies conditions that can affect a child's long-term health and survival; CDC staff create dried blood spot quality assurance materials that closely mimic these conditions, and state laboratories then use these materials to check their testing methods and results, which helps ensure tests are accurate so affected babies can be diagnosed and treated as early as possible.

Newborn Weeks is planning help, not medical advice — always follow your own doctor, midwife, or pediatrician.

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