Blood groups

Understanding Blood Groups in Grand Rapids, Michigan

Blood is essential for life. It carries oxygen and nutrients to every cell in your body and removes waste products like carbon dioxide. Most of your blood is a liquid called plasma. Suspended in the plasma are:

Red blood cells – carry oxygen
White blood cells – part of your immune system
Platelets – help your blood clot and stop bleeding

In Grand Rapids, knowing your blood type is important for safe medical care, especially during emergencies, surgery, pregnancy, or when donating blood at local centers such as Spectrum Health, Trinity Health Grand Rapids, Metro Health, Mercy Health, and American Red Cross donation sites.

The Main Blood Group Systems: ABO and Rh

ABO Blood Groups

The ABO system is the primary way blood is classified. There are four main ABO blood groups:

Group A
Group B
Group AB
Group O

Your blood group is determined by genes inherited from your parents. Each blood group is defined by specific antigens (molecules) on the surface of red blood cells. These antigens help your immune system recognize which blood cells belong in your body and which do not.

Rh Blood Type (Rh Factor)

The Rh system is the second major way blood is classified. It is controlled by a different pair of genes than the ABO system.

If you have the Rh antigen, you are Rh-positive (Rh+)
If you do not have the Rh antigen, you are Rh-negative (Rh−)

Your complete blood type is described by combining ABO and Rh systems, such as:

O positive (O+)
A negative (A−)
AB positive (AB+), etc.

In medical records at Grand Rapids hospitals like Spectrum Health or Trinity Health Grand Rapids, your blood type will be listed using this ABO + Rh format.

The 8 Main Blood Types

Together, the ABO and Rh systems create 8 main blood types:

A positive (A+)
A negative (A−)
B positive (B+)
B negative (B−)
AB positive (AB+)
AB negative (AB−)
O positive (O+)
O negative (O−)

According to the American Red Cross, blood type frequencies in the United States are approximately:

O positive – 40%
O negative – 9%
A positive – 31%
A negative – 7%
B positive – 8%
B negative – 2%
AB positive – 2%
AB negative – 1%

These patterns are generally similar in Michigan, including the Grand Rapids area, although exact percentages can vary with the local population’s ethnic background.

Why Blood Type Matching Matters in Grand Rapids Hospitals

When someone in Grand Rapids needs a blood transfusion—for example, after a car accident on icy winter roads, during surgery at Spectrum Health, or for treatment of anemia or cancer—the donated blood must be compatible with the patient’s blood type.

If incompatible blood is given:

The recipient’s immune system may attack the donor red blood cells
This can cause a serious, sometimes life-threatening reaction

Universal Donor and Universal Recipient

O negative (O−) red blood cells can be given to almost anyone in an emergency. This is why O− is often called the “universal donor” type and is heavily needed at local blood drives in Grand Rapids.
AB positive (AB+) individuals can receive red blood cells from any ABO type and are sometimes called “universal recipients” for red cell transfusions.

Even though O− can be used in emergencies, Grand Rapids hospitals still prefer to match the exact blood type whenever possible to reduce risks and preserve O− for critical situations.

The Safety of the Blood Supply in the United States and Michigan

The United States has one of the safest blood supplies in the world. In Michigan, blood donation and transfusion are tightly regulated and carefully tested. Local hospitals and blood centers:

Screen donors for health conditions
Test all donated blood for infections
Match ABO and Rh type before transfusion

If you donate blood in Grand Rapids—at an American Red Cross center, a local hospital drive, or a community event—your donation goes through a strict safety process before it is used for patients.

Rh Factor and Pregnancy: Why It Matters

Problems can occur during pregnancy if:

The mother is Rh-negative
The baby is Rh-positive

This situation is called Rh incompatibility.

How Rh Incompatibility Causes Problems

If Rh-positive blood cells from the baby cross the placenta and enter the mother’s bloodstream:

The mother’s immune system recognizes the Rh-positive cells as “foreign.”
Special white blood cells make antibodies to attack Rh-positive red blood cells.
The mother becomes “sensitized” to Rh-positive blood.

This usually does not harm the first Rh-positive baby. However, in a future pregnancy with another Rh-positive baby:

The mother’s immune system can quickly produce large amounts of antibodies.
These antibodies can cross the placenta and destroy the baby’s red blood cells.

This can lead to a serious condition called haemolytic disease of the newborn (HDN), which can cause:

Severe anemia in the baby
Jaundice
Organ damage
In severe cases, stillbirth or death shortly after birth

Preventing Haemolytic Disease of the Newborn (HDN)

HDN is now rare because it can be effectively prevented.

If a pregnant woman is Rh-negative, her healthcare provider in Grand Rapids (for example, at Metro Health, Mercy Health, or a local OB/GYN practice) will:

Test her blood type early in pregnancy
Monitor the baby’s risk
Give her a special injection called Rh immunoglobulin (RhIg) at recommended times

How Rh Immunoglobulin Works

Rh immunoglobulin is made from donated blood products and:

Destroys any Rh-positive baby red blood cells in the mother’s bloodstream
Prevents the mother’s immune system from becoming sensitized
Protects future pregnancies from HDN

Typically, Rh-negative mothers receive Rh immunoglobulin:

During pregnancy (often around 28 weeks)
Within 72 hours after giving birth to an Rh-positive baby
Sometimes after miscarriage, abortion, ectopic pregnancy, or certain procedures, if there is a chance of blood mixing

If you are pregnant in Grand Rapids, your OB/GYN or midwife will guide you through this testing and treatment as part of routine prenatal care.

Beyond ABO and Rh: Rare Blood Types and Variants

Blood types are more complex than just A, B, AB, and O. Scientists have identified:

More than 300 minor blood group antigens
Many additional blood group systems beyond ABO and Rh

Each antigen is a marker on the surface of red blood cells. Most people never need to know about these minor antigens, but they become important for:

Patients who need frequent transfusions (for example, people with sickle cell disease or certain anemias)
Patients who have had reactions to transfusions in the past
People with very rare blood types

In these cases, Grand Rapids hospitals may work with regional and national blood banks (including the American Red Cross and specialized reference laboratories) to find specially matched blood that is compatible not only for ABO and Rh, but also for these additional antigens.

As the ethnic and cultural diversity of Grand Rapids and West Michigan continues to grow, the need for diverse blood donors also increases. Donors from different backgrounds are often the best match for patients from similar backgrounds, especially for rare blood types.

Blood Donation in Grand Rapids, MI

Donating blood is a simple way to support your local community’s health. In Grand Rapids, blood is needed year-round, but especially:

During winter months, when icy roads increase accident risk
During flu season, when some regular donors are temporarily unable to give
During summer, when donation rates often drop but medical needs remain steady

Where You Can Donate or Get Help

If you want to learn your blood type, donate blood, or have questions about transfusions or pregnancy and Rh factor, you can contact:

Your primary care provider (GP/doctor) – at Spectrum Health, Trinity Health Grand Rapids, Metro Health, or other local clinics
American Red Cross – for blood donation sites and drives in the Grand Rapids area
Kent County Health Department – for community health resources and information
Grand Rapids Public Health and local community clinics – for screenings, education, and referrals

When to Talk to a Healthcare Provider

Consider speaking with a healthcare professional in Grand Rapids if:

You are pregnant or planning pregnancy and do not know your blood type
You have had a reaction to a blood transfusion in the past
You have a chronic condition (such as anemia, sickle cell disease, or cancer) that may require transfusions
You are interested in donating blood and want to know if you are eligible

Understanding your blood group—and how it affects your health—helps you make informed decisions and supports safer care in Grand Rapids hospitals, clinics, and emergency rooms.