The PlexABMR test measures the risk of rejection in which B-cells play a major role by producing antibodies against the transplanted organ. Antibody-mediated rejection (ABMR) is a less common form of rejection compared with cellular rejection. However, it has been linked to accelerated graft loss. ABMR often accompanies acute cellular rejection and other types of injury on a biopsy.
Information about the risk of ABMR can facilitate early preventive measures and improve graft health and longevity.
For details on the clinical trials conducted, please check this link.
The PlexABMRTM blood test measures the likelihood of antibody-mediated rejection by measuring whether recipient lymphocytes called B-cells show increased anti-donor activity. This activity is measured after stimulating lymphocytes from the recipient with donor or donor-like cells. To determine whether anti-donor activity is increased or decreased, it is compared with activity toward non-donor (reference) cells.
Knowledge about the likelihood of antibody-mediated rejection can be combined with clinical information to develop a treatment plan by:
- Assessing whether elevated serum creatinine indicates an increased likelihood of antobody-mediated rejection.
- Assessing the adequacy of immunosuppression with serial use.
- Optimizing the frequency of surveillance biopsies.
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1 |
Assay Category |
Lab-developed test, antigen-specific B-cell function. |
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2 |
Intended Use |
To measure the likelihood of Antibody-mediated rejection after Renal Transplantation. |
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3 |
Methodology |
Stimulation of peripheral blood leukocytes with donor and non-donor cells, flow cytometry. |
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4 |
Test Report |
Available within 30 hours of receiving a blood sample. |
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5 |
Test Readout |
Index of Rejection (IR), the IR is the ratio of the recipient B-cell activity toward donor or donor-like cells and reference cells. |
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6 |
Reference Range |
The IR is an absolute number with a range of less than 1.35 to 1.35 or greater. |
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7 |
Test Interpretation |
An IR of 1.35 or more indicates an increased likelihood of acute cellular rejection. |
Purpose
T-cell mediated rejection and antibody-mediated rejection differ in immune pathways and immune cells by which they cause injury to the transplanted organ. The PlexABMRTM blood test is the first cell-based test to measure the risk of antibody-mediated rejection.
Knowledge about the risk of antibody-mediated rejection can be combined with available clinical data to plan additional treatment for your patient.
Rationale
- Renal transplant rejection is usually suspected because of elevated serum creatinine. Elevated creatinine is also seen with infection and mechanical blockage. Elevated creatinine does not distinguish between T-cell-mediated and antibody-mediated rejection. A “for-cause” biopsy is needed to confirm rejection and the type of rejection. Up to half of “for-cause” biopsies do not show rejection.
- Rejection can also occur without affecting serum creatinine, especially if immunosuppression is suboptimal. Surveillance biopsies are performed at predetermined intervals to detect ‘silent’ rejection and assess immunosuppression.
- The PlexABMRTM blood test measures the likelihood of rejection. This knowledge can be combined with clinical information to develop a treatment plan. Benefits include:
- Enhancing the diagnostic yield of "for-cause" biopsies.
- Optimizing the frequency of surveillance biopsies.
- Improving the long-term management of immunosuppression directed toward antibody-mediated rejection with serial use.
Intended Use
To assess the likelihood of antibody-mediated rejection after renal transplantation.
Procedure
- PlexABMRTM is a functional cell-based blood test which measures the immune response of recipient lymphocytes to donor lymphocytes in cell culture. The immune response is measured as B-cells that express an inflammatory marker, CD154.
- The test requires whole blood in sodium heparin tubes to be shipped at ambient temperature for overnight delivery to Plexision’s laboratory. Eight-10 mL whole blood samples are needed from adults, and five-8 mL samples are needed from children.
- Results are expressed as an index of rejection, which is a measure of the likelihood of antibody-mediated rejection.
- Results are reported the day after the blood sample is received at the laboratory. For blood samples shipped overnight to Plexision’s laboratory, results are reported within two days of obtaining the blood sample from the patient
Performance
- The PlexABMRTM test is performed in Plexision's CLIA- approved laboratory.
- Performance has been evaluated in relationship to “for-cause” biopsies in renal transplant recipients in a multi-center study.
- The test identifies renal transplant recipients experiencing antibody-mediated rejection with positive predictive value of 81% and negative predictive value of 75%.
Benefits
Determining whether antibody-mediated rejection is likely is important in deciding:
- Whether immunosuppression aimed at this type of rejection is sufficient.
- Whether anti-rejection medications can be decreased or not.
- Whether additional tests are needed to confirm rejection.
Knowledge about the likelihood of antibody-mediated rejection from the PlexABMRTM test can be combined with other clinical data by your healthcare provider to make clinical decisions.
Insurance Coverage
Plexision will bill the patient's insurance plan and work directly with the insurer for payment. Plexision will assist with the cost of PlexABMR™ if there is no insurance coverage. For additional information, call 1.855.753.9474 or email info@plexision.com
Sample & Shipping
| # | CATEGORY | DETAILS |
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1 |
Sample Type |
Whole blood collected in a sodium heparin (green-top) tube. |
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2 |
Volume |
8-10 mL in adults and 5-8 mL in children. |
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3 |
Transport Conditions |
Ship priority overnight, at room temperature. The sample must get to Plexision within 30 hours of the phlebotomy. |
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4 |
Specimen Stability |
30 hours at room temperature from the time of the phlebotomy. |
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5 |
Sample Discard Criteria |
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How to order
| # | CATEGORY | DETAILS |
|---|---|---|
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1 |
Test Brochure | View and download the product brochure here. |
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2 |
Ordering Tests |
Please complete this form, print, and fax it to 412-224-2776. |
PlexABMRTM is a blood test that helps your healthcare provider determine whether antibody-mediated rejection is likely after renal transplantation.
Kidney transplant recipients of any age can benefit from the PlexABMRTM test.
The PlexABMRTM test must be ordered by your healthcare provider. The test requires a sample of blood of two teaspoons. This sample is to be shipped overnight to Plexision’s laboratory for analysis. Results are sent to your healthcare provider within a day of your sample arriving at the laboratory. Your healthcare provider will help you understand the results.
Results are ready within 30 hours after the laboratory receives the blood sample.
The PlexABMRTM test determines whether the recipient's B-cells that makes antibodies to the transplanted organ is reacting excessively toward the transplanted organ. This type of immune response occurs during antibody-mediated rejection, and can be measured in a type of white blood cell called the B-cell or B-lymphocyte. When present, this increased immune response tells your healthcare provider whether transplant rejection is likely or not.
The results are reported as an Index of Rejection (IR). An index less than 1.35 implies a decreased likelihood of antibody-mediated rejection. An index of 1.35 or greater implies an increased likelihood of antibody-mediated rejection.
Determining whether antibody-mediated rejection is likely is important in deciding whether the amount of anti-rejection medications that is being used to manage antibody-mediated rejection is enough, whether these anti-rejection medications can be decreased further, or whether additional tests are needed to confirm whether antibody-mediated rejection is already present or not. Knowledge about the likelihood of antibody-mediated rejection can be combined with other clinical data by your healthcare provider to make clinical decisions.
The PlexABMRTM test must be ordered by your healthcare provider. The test requisition form is provided here. The completed form can be faxed to 412-224-2776. If there are any questions, please contact (855) PLE.XISION (753.9474) or 412-224-2504.
Plexision will bill your healthcare facility or your insurance plan as indicated on the requisition form. Plexision’s patient assistance plans will assist you with the cost of PlexABMRTM if there is no insurance coverage.
- https://clinicaltrials.gov/study/NCT03916822
- Transplantation. 2010 Dec 15;90(11):1226-31. PMID: 20881665.
PlexABMRTM is a lab-developed test and is not FDA-approved.