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Aborhbldfather

Published: August 9, 2026Updated: August 10, 2026

This test determines the father's blood type (ABO group) and Rh factor to assess potential risks during pregnancy.

Quick summary

{"The test identifies the father's ABO blood type (A, B, AB, or O) and Rh factor (positive or negative)","Results help predict the risk of blood type incompatibility between mother and baby","Rh-negative fathers with Rh-positive partners may need additional monitoring during pregnancy","The test is performed on a simple blood sample","Knowing the father's blood type helps healthcare providers plan appropriate prenatal care"}

Medically reviewed by WellAlly Editorial TeamLast reviewed August 10, 2026Editorial policy

Key facts at a glance

LOINC
90906-9
Short code
ABO/Rh
Synonyms
ABO + Rh Bld Father
Category
chemistry
Sample
serum
Container
Red top serum separator tube (SST) or plain red top tube; alternatively EDTA tube (lavender top) acceptable
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
0–150 years
Method
Serum agglutination (tube, gel card, or slide method) with anti-A, anti-B, anti-AB, and anti-D reagents
CPT
86900 (ABO blood typing), 86901 (Rh blood typing)
SNOMED
365689006 (Blood group typing), 168713003 (ABO blood group), 79899005 (Rh blood group)
Specimen volume
2-5 mL of venous blood
Stability
Room temperature: 24-72 hours; Refrigerated (2-8°C): 5-7 days; Frozen (-20°C or below): not recommended for serum
Hemolysis max
50
Lipemia max
300
Icterus max
20
TAT
1–24 hours
Order
routine

What is this test?

The Father's ABO and Rh Group Type test is a blood test that determines the father's blood type classification. It identifies two important characteristics: the ABO blood group (A, B, AB, or O) and the Rh factor (either Rh-positive or Rh-negative). This information is primarily used during pregnancy to assess potential compatibility issues between the father's blood type and that of the mother and developing baby.

Why is this test important during pregnancy?

Understanding the father's blood type helps healthcare providers predict and prevent complications that may arise from blood type incompatibility. The most significant concerns include Rh incompatibility, which can cause hemolytic disease of the newborn (HDN), and ABO incompatibility, which may lead to jaundice in newborns. If the father is Rh-positive and the mother is Rh-negative, special precautions may be needed to protect the baby.

How is the test performed?

A healthcare professional will draw a small blood sample from a vein in the father's arm. The sample is then sent to a laboratory where it is analyzed to determine the ABO blood group and Rh factor. No special preparation is required before the test, and it is generally quick and low-risk.

What do the results mean?

The test results will show whether the father's blood type is A, B, AB, or O, and whether it is Rh-positive or Rh-negative. If the father is Rh-negative and the mother is Rh-positive, there is generally no concern about Rh incompatibility. However, if the father is Rh-positive and the mother is Rh-negative, healthcare providers may recommend Rh immunoglobulin injections to prevent complications in the baby.

Reference range

Qualitative result: ABO group (A, B, AB, or O) and Rh type (positive or negative). Reference range is not applicable as this is a categorical blood typing test.N/A

Specimen: serum

No fasting required. No special preparation needed. Inform laboratory of recent blood transfusions (within last 3 months) as this may affect results. Provide accurate patient identification and demographic information.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Frequently asked questions

Does this test hurt?
The test involves a simple blood draw, which may cause brief discomfort or a slight pinch. The procedure is quick and typically well-tolerated.
How long does it take to get results?
Results are usually available within a few days, though this may vary depending on the laboratory. Your healthcare provider will inform you when the results are ready.
What happens if the father is Rh-negative and the mother is Rh-positive?
This combination generally does not pose a risk for Rh incompatibility. The baby is likely to be Rh-negative like the father, so no special treatment is typically required.
Can the father's blood type change over time?
No, a person's ABO and Rh blood type is determined at birth and remains constant throughout life. It cannot change naturally.
Is this test only done during pregnancy?
While commonly performed as part of prenatal care, blood typing may be done for various reasons, including before surgery, blood donation, or to determine transfusion compatibility.
  1. 1
    American College of Obstetricians and Gynecologists - Blood Type and RhSource
  2. 2
    Mayo Clinic - Blood typingSource
  3. 3
    National Institutes of Health - Rh IncompatibilitySource

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 10, 2026. · Read our editorial policy