Article 014: Should Every Baby in America Have Their Blood Type Tested at Birth?

Every American receives a birth certificate. Nearly every child undergoes newborn screening. Hospitals collect enormous amounts of information surrounding birth, from weight and length to medical screening results. Yet one of the most fundamental characteristics of a person's blood may never be determined unless there is a specific medical reason to test it.

Many Americans reach adulthood without knowing whether they are A, B, AB, or O, or whether they are Rh-positive or Rh-negative. That raises a surprisingly simple question. Should every baby born in the United States have their ABO and Rh blood type determined at birth, recorded permanently in their medical record, and included on their birth certificate?

There are reasonable arguments against making this universal. Blood type alone cannot replace compatibility testing before a transfusion, and healthy newborns do not currently need ABO/Rh testing simply for the sake of knowing their blood type. But modern medicine has also made obtaining this information relatively straightforward, and the information can remain relevant throughout an individual's entire life. Perhaps it is time to reconsider whether blood type should be treated as something we discover only when circumstances require it.

We Already Test Some Babies at Birth

Blood typing newborns is certainly not unusual in American medicine. The American Academy of Pediatrics recommends determining an infant's blood type when the mother's prenatal antibody screen is positive or unknown. When the mother is RhD-negative, determining the infant's Rh type is important because it helps determine whether the mother needs postpartum Rh immune globulin, commonly called RhIG.

When the pregnancy presents no such indication, determining the baby's ABO and Rh type isn't necessarily required. For example, the AAP says that when the mother is O-positive and has a negative antibody screen, determining the infant's blood type may be optional when appropriate bilirubin surveillance and follow-up are provided. 

Consequently, some Americans have known their blood type essentially since birth, while others may not discover it until they donate blood, become pregnant, undergo surgery, or encounter another situation requiring blood-group testing. Universal testing would change that.

The Umbilical Cord Makes the Idea More Practical

One obvious objection to universal newborn blood typing would be the idea of performing another blood draw on every baby merely to determine information that may not immediately be medically necessary. But there is an interesting alternative. Blood remaining in the umbilical cord after birth belongs to the infant and can be used for laboratory testing. In a 2025 clinical report, the American Academy of Pediatrics described postnatal cord blood sampling as a painless and simple method for obtaining neonatal blood and said it can reliably be used for blood typing and crossmatching, among numerous other laboratory tests.

The evidence is particularly compelling for blood typing. The AAP report describes a study comparing postnatal cord blood with blood obtained by infant heel stick and reports 100% concordance for ABO and Rh typing.

That changes the discussion considerably. A universal blood-typing program would not necessarily require sticking every newborn with another needle merely to discover their blood type. In hospitals equipped to collect an appropriate cord sample, the information could potentially be obtained from blood remaining in the cord after delivery.

Give Every Person Knowledge of Their Own Blood Type

The most obvious benefit would simply be knowledge. A child's ABO and RhD type could be determined at birth, entered into the electronic medical record, given to the parents, and eventually made available to the child themselves.

Blood type is a lifelong biological characteristic under ordinary circumstances. Unlike weight, blood pressure, address, or telephone number, someone's inherited ABO type does not normally change as they grow older. There are rare medical circumstances that can complicate apparent blood-group status, such as hematopoietic stem-cell transplantation, which is another reason a historical result should never replace current testing when transfusion decisions are being made.

As a piece of baseline medical information, a properly obtained blood type can remain useful for decades.

Rh-Negative Status Makes the Question Particularly Interesting

RhD provides another argument for knowing blood type early. An RhD-negative individual lacks conventional expression of the D antigen. Exposure to D-positive red cells can cause some D-negative individuals to produce anti-D antibodies. This becomes particularly important in transfusion medicine and pregnancy.

Knowing from childhood that someone is Rh-negative would not eliminate the need for future testing. It would, however, mean that this medically important characteristic had already been identified and documented long before pregnancy, surgery, blood donation, or an emergency ever occurred.

There is another benefit that has become clearer through modern genetics. As we discussed in our article about full RHD deletion, weak D, partial D and DEL, RhD is considerably more complicated than a simple positive-or-negative genetic switch. An unusual or discrepant Rh result discovered early could potentially become part of the person's permanent medical history rather than being rediscovered years later.

Would It Help in an Emergency?

Yes, but probably not in the way people initially imagine. Imagine an unconscious trauma patient arriving at an emergency department with a birth certificate saying: O-Negative 

It might seem obvious that doctors could simply trust that information and immediately select blood accordingly. Modern transfusion medicine is deliberately more cautious. Before routine transfusion, laboratories perform pretransfusion testing that includes patient identification, determination of the patient's current ABO and Rh type, antibody screening, and appropriate compatibility testing. AABB standards also call for reviewing historical ABO/Rh information and comparing it with current results.

That distinction is important. A historical blood type can be valuable information, but it isn't normally a substitute for properly identifying and testing the patient when circumstances permit. In a life-threatening hemorrhage, doctors may not have enough time to wait for every laboratory result. Emergency transfusion protocols exist specifically for those situations, including the use of group O blood or other emergency blood strategies until appropriate testing can be completed. A person's birth certificate therefore would not replace the emergency transfusion system.

But Historical Blood-Type Records Still Have Value

The fact that hospitals would retest the patient doesn't mean an old result is useless. In fact, modern transfusion standards specifically recognize the value of historical records. AABB standards require a process for reviewing previous ABO group, Rh type, blood-typing difficulties, clinically significant antibodies, transfusion reactions, and special transfusion requirements and comparing relevant historical information with current testing.

That suggests an important distinction. The purpose of recording someone's blood type from birth wouldn't be to tell future doctors, "Never test this person again." It would tell them, "This is an established historical result that can be compared with today's testing." If today's result disagrees with the historical record, that discrepancy itself becomes something worth investigating.

What About Putting Blood Type on the Birth Certificate?

This part of the proposal is more debatable. A medical record is designed to contain medical information. A birth certificate is primarily a government vital record establishing facts surrounding a person's birth and identity. There are therefore legitimate questions about whether blood type belongs on the legal certificate itself.

Privacy is one consideration. Although ABO/Rh type isn't remotely comparable to publishing someone's entire genome, it is still biological information. Another concern is accuracy. A typographical error on a legal document could follow someone for decades if people incorrectly assumed the certificate was authoritative for transfusion purposes.

Neither problem makes the idea impossible. A birth certificate could contain a clearly labeled field such as, ABO/Rh Blood Type at Birth: O Negative. Along with language making clear that the entry represents a historical laboratory result and must not substitute for required pretransfusion testing. Alternatively, states could place the information on a companion medical birth record rather than the legal certificate.

Why Put It in Both Places?

There is nevertheless an argument for doing both. Electronic medical records are not perfectly universal. People change physicians. Families move between states. Hospitals merge and close. Health systems use different electronic platforms. Records can become difficult to locate decades later.

A birth certificate, on the other hand, is one of the few records intended to follow someone throughout life. Recording the blood type both in the medical record and on a durable personal document would create redundancy. The electronic record would provide the clinical history, while the birth certificate or accompanying official record would give the individual a permanent personal reference.

Again, neither should authorize transfusion without appropriate testing. Their value would be knowledge and historical documentation.

There Would Be Costs

Universal programs aren't free merely because the underlying test is relatively simple. Testing millions of newborns every year would require reagents, laboratory personnel, information systems, quality-control procedures, documentation, and procedures for handling unusual or inconclusive results.

Even cord blood collection requires proper procedures. The AAP emphasizes that cord samples need appropriate collection methods and quality controls. Policymakers would therefore need to answer an important question. Does the lifetime value of universally documented ABO/Rh type justify the additional cost of testing babies who have no immediate clinical indication for it?

That question deserves an actual health-economic analysis rather than an assumption in either direction.

There Is Another Limitation: ABO/Rh Is Only Part of the Story

Knowing that someone is O-negative does not tell physicians everything necessary for safe transfusion. Human red cells carry hundreds of recognized blood-group antigens. Patients can develop clinically significant antibodies against antigens outside the familiar ABO and RhD systems, particularly following transfusions or pregnancies.

That is why pretransfusion testing includes an antibody screen in addition to determining ABO and RhD. A birth certificate saying O-negative therefore cannot mean, "This person can automatically receive any O-negative unit for the rest of their life." It means something much narrower. "At birth, laboratory testing determined this person's ABO group to be O and their RhD type to be negative." That is still useful information. It simply isn't the whole transfusion picture.

Blood Donation Could Benefit Too

There may also be a public-health benefit that is harder to quantify. People don't understand the importance of their blood type until they donate blood. Blood centers determine the ABO and Rh type of donated blood as part of routine testing. 

Imagine instead that every American grew up knowing their blood type. People with particularly important donor types could learn about their potential role in the blood supply much earlier. O-negative individuals, for example, could be educated about the particular demand for their red cells, while AB donors could learn about the usefulness of their plasma.

Universal knowledge wouldn't guarantee that people donate, but it could make blood-group education part of ordinary health education rather than something many people encounter for the first time as adults.

The Case for a National Blood-Type-at-Birth Policy

A reasonable national policy could therefore be surprisingly straightforward. Every newborn could have ABO and RhD typing performed using properly collected postnatal cord blood when feasible. The laboratory-confirmed result could be entered permanently into the child's medical record and provided to the parents. States could additionally record the result on the birth certificate or an accompanying official health record, clearly identifying it as a historical blood-group result rather than authorization for transfusion without current compatibility testing.

Unusual RhD results could be handled according to appropriate laboratory standards rather than forced into an inaccurate positive-or-negative category. Such a program would not revolutionize emergency transfusion medicine. Hospitals would still need to identify patients, type their blood, screen for antibodies, and perform compatibility testing when required. Emergency protocols would still exist for situations where there isn't enough time.

The potential benefit is simpler. Every American would begin life knowing one of the most fundamental characteristics of their blood.

A Small Test With a Lifetime of Information

The strongest argument for universal blood typing at birth may ultimately be its simplicity. The technology already exists. Cord blood is already accepted as a reliable source for neonatal ABO and Rh typing when those tests are medically indicated. The information can remain relevant throughout a person's life.

The question is therefore not whether we can determine every baby's blood type. We can. The question is whether the United States believes that permanently knowing this information is valuable enough to make universal testing worthwhile.

There are legitimate questions about cost, privacy, implementation, and whether blood type belongs specifically on a legal birth certificate. There are also important safeguards that must accompany the idea, particularly the understanding that a decades-old blood-type record should never replace required pretransfusion testing.

Those limitations also do not eliminate the larger question. 

We already preserve a person's name, place of birth, date of birth, parentage, and other information from the beginning of life. Perhaps there is a reasonable argument that ABO and RhD blood type should become part of that permanent record too.