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Abogroupphsctbld

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

This test determines your blood type after a hematopoietic stem cell transplant, which is crucial for safe blood transfusions and monitoring transplant success.

Quick summary

{"Stem cell transplants can change your blood type permanently","Regular testing helps ensure safe blood transfusions","Mixed blood types (chimerism) may occur during the transition period","The test monitors how well the new stem cells are producing blood cells","Results help your healthcare team provide the correct blood products"}

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

Key facts at a glance

LOINC
93931-4
Short code
ABO-POSTHSCT
Synonyms
ABO Group p HSCT Bld
Category
chemistry
Sample
whole-blood
Container
EDTA purple-top tube (K2-EDTA) or ACD (yellow-top) tube
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
0–120 years
Method
Column agglutination technique (gel card) or tube agglutination with forward (cell) and reverse (serum) typing
CPT
86900
SNOMED
365761006
Specimen volume
3-5 mL whole blood
Stability
Room temperature (20-25°C): 72 hours; Refrigerated (2-8°C): 7 days. Do not freeze.
Hemolysis max
0
Lipemia max
0
Icterus max
0
TAT
4–24 hours
Order
routine

What is this test?

The ABO blood type test after hematopoietic stem cell transplant is a laboratory test that determines your blood group (A, B, AB, or O) after receiving stem cells from a donor. This test is different from a routine blood type test because it specifically monitors the blood type produced by the donor's stem cells that have engrafted in your body.

Why is this test important after a stem cell transplant?

When you receive a hematopoietic stem cell transplant, the donor's stem cells gradually take over the job of producing new blood cells. Over time, the blood type you produce will match the donor's blood type rather than your original type. This test tracks this transition and helps your medical team provide the correct blood type for any transfusions you may need.

How is the test performed?

A healthcare professional will draw a small blood sample from a vein in your arm. The sample is then tested in a laboratory to determine your current ABO blood type. The test looks for specific antigens (proteins) on the surface of your red blood cells and antibodies in your blood plasma.

What is blood type chimerism?

During the transition period after transplant, you may have both your original blood cells and donor blood cells circulating in your body. This is called chimerism. Your test results might show a mixed pattern during this time. Your healthcare team will monitor this to ensure the donor cells are successfully engrafting.

How often will I need this test?

The frequency of testing varies depending on your specific situation. Typically, your blood type will be tested regularly in the months following your transplant until it stabilizes to the donor's blood type. Your transplant team will determine the appropriate testing schedule for you.

Reference range

Result reported as blood type A, B, AB, or O with Rh status. Post-transplant, may show donor type, recipient type, or mixed field (chimerism). Reference range is qualitative (correctly typed) not numerical.N/A

Specimen: whole-blood

No fasting required. Inform laboratory of recent transfusion (within 3 months) as this may affect results. Provide complete transfusion history and HSCT date.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Frequently asked questions

Will my blood type change after the transplant?
Yes, eventually your blood type will change to match your donor's blood type. This process can take several months to a year or more. During this transition period, your blood type may show as a mixed type.
Why do I need to know my new blood type?
Knowing your new blood type is critical for receiving safe blood transfusions. If you need blood products after your transplant, your medical team must give you blood that matches your current blood type—the donor's type—not your original type.
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 generally well-tolerated.
What if my blood type doesn't change?
If your blood type doesn't change to match the donor's type over time, it may indicate that the stem cells are not engrafting properly. Your transplant team will investigate and discuss options with you.
Can I still donate blood after my transplant?
Generally, transplant recipients cannot donate blood for a period of time after transplantation due to safety concerns and the need to monitor their recovery. Your healthcare team will advise you on when and if blood donation becomes possible.
  1. 1
    American Red Cross - Blood TypesSource
  2. 2
    National Cancer Institute - Stem Cell TransplantsSource
  3. 3
    LOINC Code ReferenceSource

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