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Aborhinfantbld

Published: August 9, 2026Updated: August 16, 2026

A blood test that determines your baby's blood type (A, B, AB, or O) and Rh factor (positive or negative).

Quick summary

{"This test identifies your baby's blood type and Rh factor","It helps check for blood compatibility issues between mother and baby","Results are important for safe blood transfusions if needed","Rh-negative mothers may need special care during pregnancy","The test uses a small blood sample from your baby"}

Medically reviewed by WellAlly Editorial TeamLast reviewed August 16, 2026Editorial policy

Key facts at a glance

LOINC
93906-6
Short code
ABO-Rh Infant
Synonyms
ABO + Rh infant Bld
Category
chemistry
Sample
whole-blood
Container
EDTA tube (lavender top/purple cap) - K2-EDTA or K3-EDTA
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
0–2 years
Method
Serum/plasma agglutination with anti-A, anti-B, anti-AB, anti-D (Rh) reagents; column agglutination technology (CAT) or tube method
CPT
86900 (ABO blood typing); 86901 (Rh blood typing)
SNOMED
365679006 (ABO blood group); 127778009 (Rh blood group); 169992004 (Blood typing during infancy)
Specimen volume
3-5 mL whole blood (minimum 1 mL for pediatric tubes)
Stability
Room temperature (20-25°C): 72 hours; Refrigerated (2-8°C): up to 7 days. Do not freeze.
Hemolysis max
0
Lipemia max
0
Icterus max
0
TAT
1–24 hours
Order
routine

What is this test?

The ABO and Rh blood type test is a simple blood test that determines two important things about your baby's blood: (1) the ABO blood group (A, B, AB, or O) and (2) the Rh factor (Rh-positive or Rh-negative). This test is performed specifically during infancy to help identify potential blood type incompatibilities between the mother and baby that could cause health problems.

Why is this test done for babies?

During infancy, this test is important for several reasons: (1) To check for ABO or Rh incompatibility between the mother and baby, which can cause jaundice or anemia in newborns; (2) To determine if a Rh-negative mother needs Rh immunoglobulin injections to prevent complications in future pregnancies; (3) To establish the baby's blood type for medical records; (4) To ensure safe blood transfusion if the baby ever needs one.

How is the test performed?

A healthcare provider will collect a small blood sample from your baby's heel (heel stick) or from a vein in the arm. The blood is then sent to a laboratory where it is mixed with special antibodies to determine how the red blood cells react. This helps identify the exact blood type and Rh factor. The procedure only takes a few minutes and is generally well-tolerated by infants.

Are there any risks?

The risks are minimal and include slight pain during the blood draw, possible bruising or swelling at the puncture site, and rarely, infection. The benefits of knowing your baby's blood type far outweigh these minor risks. Your healthcare provider will ensure the procedure is done safely and comfortably for your little one.

Reference range

Expected result: A, B, AB, or O; Rh: Positive or Negative. Reference range is not applicable as this is a qualitative test determining blood group phenotype.N/A

Specimen: whole-blood

No special preparation required. For infant testing, ensure proper patient identification and maternal blood group documentation if available. No fasting required.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Frequently asked questions

Does this test hurt my baby?
Your baby may feel a brief pinch or discomfort during the blood draw, similar to a vaccination. The procedure is quick and healthcare providers are experienced in making infants as comfortable as possible. The discomfort is temporary and subsides quickly.
How long does it take to get results?
Results are typically available within a few hours to one day, depending on the laboratory. Your healthcare provider will discuss the results with you during a follow-up appointment or phone call.
What if my baby has a different blood type than me?
This is normal and not a cause for concern. Your baby inherited their blood type from both parents. Different blood types do not cause health problems unless there is a specific incompatibility that your healthcare team will monitor.
Does my baby need to fast before this test?
No fasting is required for a blood type test. Babies can eat normally before and after the test. This makes the process easier for both you and your little one.
Will my baby need more tests after this?
Based on the results, your doctor may recommend additional tests if there are concerns about blood type incompatibility. This might include monitoring bilirubin levels for jaundice or antibody tests in certain situations. Your healthcare provider will explain any follow-up testing if needed.
  1. 1
    American Red Cross - Blood TypingSource
  2. 2
    Mayo Clinic - Blood TypeSource

Click any link to access the full source. PubMed Central (PMC) links provide free full-text access.

This information is for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment.

Medical Disclaimer

This content is for general informational and educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the guidance of a qualified healthcare provider with any questions you have about a medical condition, and never disregard professional medical advice or delay seeking it because of something you read here.

If you think you may have a medical emergency, call your local emergency number or go to the nearest emergency department immediately.

Medically reviewed by WellAlly Editorial Team Last reviewed August 16, 2026. · Read our editorial policy