Bcellxmbldql
A laboratory test that checks if you have pre-formed antibodies that might react against a donor's B cells before organ transplantation.
{"Evaluates compatibility between donor and recipient before transplantation","Detects pre-formed antibodies that could cause transplant rejection","A positive result means the transplant may not be safe to proceed","Performed on a blood sample from both donor and recipient","Critical test for determining kidney and other organ transplant eligibility"}
Key facts at a glance
- LOINC
- 46715-9
- Short code
- BCXM
- Synonyms
- B Cell XM Bld Ql
- Category
- chemistry
- Sample
- whole-blood
- Container
- ACD (acid citrate dextrose) tube (yellow top) preferred; EDTA (lavender top) or sodium heparin (green top) tubes also acceptable
- Units
- N/A
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- ≥ 0 years
- Method
- Flow cytometry using fluorescently labeled anti-human immunoglobulin reagents to detect donor-specific antibodies binding to recipient B lymphocytes
- CPT
- 86825
- SNOMED
- 3163007
- Specimen volume
- 10 mL whole blood (minimum 5 mL for pediatric patients)
- Stability
- Room temperature: 24 hours; Refrigerated (2-8°C): 48 hours; Do not freeze. Specimen should be processed within 24 hours of collection for optimal lymphocyte viability.
- Hemolysis max
- 0
- Lipemia max
- 0
- Icterus max
- 0
- TAT
- 4–24 hours
- Order
- routine
What is this test?
The B cell crossmatch test is a critical pre-transplant compatibility test that checks whether your immune system has pre-formed antibodies that could attack a potential donor's B cells. B cells are a type of white blood cell that produces antibodies. If you have been exposed to certain antigens through previous transplants, blood transfusions, pregnancies, or infections, you may have developed antibodies that could recognize and attack the donor's cells. This test mixes your blood serum with the donor's B cells to see if a reaction occurs.
How is the test performed?
A blood sample will be drawn from you (the recipient) and also from the potential donor. Your serum is mixed with the donor's B cells in a laboratory. Technicians then look for signs of reaction, such as cell damage or death, which would indicate the presence of donor-specific antibodies. The test result is reported as either positive (antibodies present and reactive) or negative (no detectable reactive antibodies).
What do the results mean?
A negative crossmatch means no detectable antibodies against the donor's cells were found, suggesting the transplant may proceed safely. A positive crossmatch indicates that antibodies against the donor were detected, which significantly increases the risk of acute rejection. In most cases, a positive crossmatch means the transplant should NOT proceed, as it could lead to immediate and severe rejection of the organ.
Reference range
Negative (No donor-specific antibodies detected on B lymphocytes). Positive crossmatch indicates presence of donor-reactive antibodies and is generally a contraindication to transplantation.N/A
No fasting required. Patients should inform the laboratory of all medications, particularly immunosuppressants, rituximab, or recent blood transfusions (within 14 days) which may affect results. Recent plasmapheresis or IVIG administration should be documented.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
◆Associated findings1
Frequently asked questions
Why is the B cell crossmatch important before a transplant?
Does a positive crossmatch mean I can never receive a transplant?
How long does it take to get crossmatch results?
Will I need this test repeated if I'm on a transplant waiting list?
Is this test different from a blood type matching test?
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