Understanding Your Medical Lab Test: A Patient Guide to Testing, Reasons, and Results
This test identifies the ABO and Rh blood type of a blood product unit after a patient experiences a transfusion reaction to determine if a blood type mismatch occurred.
{"Tests the blood type (ABO/Rh) of the blood product unit, not the patient","Performed when a patient has an adverse reaction during or after blood transfusion","Helps identify if the wrong blood type was transfused","Results guide treatment of the transfusion reaction","Essential for patient safety and preventing future errors"}
Key facts at a glance
- LOINC
- 46268-9
- Short code
- ABO/Rh Type Post-Transfusion Reaction
- Synonyms
- ABO + Rh p transf rx Bld BPU
- Category
- chemistry
- Sample
- whole-blood
- Container
- EDTA tube (lavender/purple top) or dedicated blood bank sample tube
- Units
- N/A
- Ref low
- 0.8
- Ref high
- 1.2
- Critical range
- — – 5 N/A
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- 18–65 years
- Method
- Blood bank serology using tube agglutination or gel column technique with anti-A, anti-B, anti-D (Rh) reagents and reverse grouping with A1 and B cells
- CPT
- 86900
- SNOMED
- 302497004
- Specimen volume
- 2-3 mL of whole blood from the blood product segment or unit
- Stability
- Room temperature: 72 hours; Refrigerated (2-8°C): 7 days; Do not freeze
- Hemolysis max
- 0
- Lipemia max
- 0
- Icterus max
- 0
- TAT
- 1–4 hours
- Order
- routine
This test involves collecting a small sample from your body, such as blood, urine, or tissue, which is then analyzed in a laboratory to measure specific substances, cells, or markers. It gives your healthcare provider objective information about how your body is working and helps detect changes that may not be noticeable during a physical exam alone.
This test determines the ABO and Rh blood type of a blood product unit (such as red blood cells, platelets, or plasma) after a patient experiences a transfusion reaction. A transfusion reaction occurs when a patient's immune system reacts negatively to the transfused blood product. This test is performed on the remaining blood product in the bag, not on the patient's own blood.
Your doctor may order this test to help diagnose a medical condition, monitor an illness you already have, check how well a current treatment is working, or screen for potential health problems before symptoms appear. The results guide decisions about your ongoing care and any additional testing that may be needed.
When a patient has symptoms during or after a blood transfusion—such as fever, chills, rash, difficulty breathing, or dark urine—the healthcare team must determine if the reaction was caused by a blood type incompatibility. This test verifies that the correct blood type was given to the patient. If the blood product's type doesn't match the patient's type, it could cause a serious or life-threatening reaction.
Your results show whether your measurements fall within the normal reference range for the laboratory. Values outside that range do not automatically mean you have a serious disease, since factors such as diet, medications, hydration, and stress can affect them. Your provider will interpret the numbers together with your symptoms, medical history, and other tests, then explain what they mean and discuss any follow-up steps with you.
The test will show the blood type of the blood product unit, such as A+, A-, B+, B-, AB+, AB-, O+, or O-. Your healthcare provider will compare this result with your own blood type (which was determined before the transfusion) to see if they are compatible. If there is a mismatch, this explains the transfusion reaction and helps guide treatment.
Reference range
INR: 0.8-1.2 (warfarin: 2.0-3.0)N/A
No fasting required. Test is performed on the transfused blood product unit, not patient specimen. Verify product identification and expiration before testing.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
This test is critical for investigating transfusion reactions. If a blood type mismatch is found, it indicates a serious error in blood banking or administration that must be reported and corrected. The results also help healthcare providers treat the reaction appropriately and ensure the patient receives correct blood products in the future. This test is part of a comprehensive investigation that may also include testing the patient's blood and the pre-transfusion sample.
Frequently asked questions
Why is the blood product tested, not my own blood?
How long does it take to get results?
What happens if a mismatch is found?
Is this test painful?
Sources
- 1
- 2
- 3
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.
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