- PlexAPRTM test is a lab-developed blood test for the RAPID measurement of the risk of rejection of transplanted abdominal organs. This rejection may be due to recipient T-cells which injure the transplanted organ directly, or anti-donor antibodies, which are produced by B-cells of the recipient.
- Rejection is diagnosed with biopsies. Biopsies are performed when dysfunction of the transplanted organ is suspected from clinical symptoms and blood tests.
- Biopsies are invasive, take some time to arrange and do not clearly distinguish between some types of viral infection which may co-exist with rejection.
- Rapid non-invasive measurement of the risk of rejection within a few hours can permit the clinician to react sooner and improve management of transplanted organs experiencing organ dysfunction, while confirmatory biopsies are being arranged.
- The principles of this test system are described here. The test measures the ability of B-cells, a type of blood lymphocyte, to present donor antigen, relative to presentation of non-donor (reference) antigen.
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To order tests or ask any questions, please reach us via email info@plexision.com or call us at +1 (855) 753-9474.
The PlexAPR test is a rapid test that measures the risk of any type of rejection of transplanted abdominal organs. This rejection may be due to T-cells which injure the transplanted organ directly, or B-cells, which produce antibodies against the transplanted organ.
- PlexAPRTM is a lab-developed blood test for RAPID measurement of the risk of rejection of transplanted abdominal organs. Test results are available on the day blood samples are received at Plexision's reference laboratory. The test measures the ability of B-cells, a type of blood lymphocyte, to present donor antigen, relative to presentation of non-donor (reference) antigen.
- Knowledge about rejection-risk can be combined with clinical information to develop a treatment plan by the transplant physician.:
- Assessing whether dysfunction of the transplanted liver or intestine indicates increased risk of acute cellular rejection
| # | CATEGORY | DETAILS |
|---|---|---|
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1 |
Assay Category |
Lab-developed test, presentation of donor antigen by B-cells. |
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2 |
Intended Use |
To RAPIDLY measure the risk of rejection of transplanted abdominal organs. |
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3 |
Methodology |
Presentation of donor antigen by B-cells. |
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4 |
Test Report |
Available within 6 hours of receiving the blood sample. |
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5 |
Test Readout |
Antigen Presenting Index (API), is the ratio of B-cell frequencies that present donor antigen and B-cell frequencies that present reference antigen. |
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6 |
Reference Range |
The API is an absolute number with a range less than 1.1 to 1.1 or greater. |
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7 |
Test Interpretation |
An API of 1.1 or greater indicates increased risk of rejection. |
Purpose
Knowledge about the risk of rejection can be combined with available clinical data to plan additional treatment for the transplanted subject.
Rationale
- Rejection of transplanted abdominal organs is usually suspected because the recipient's clinical condition and/or laboratory tests which measure organ function are abnormal. These changes can also occur with infection and mechanical blockage. A "for cause" biopsy is needed to confirm rejection. Up to half of all "for cause" biopsies do not show rejection. Biopsies results can sometimes take longer that 24 hours.
- Rejection can also occur without changes in clinical condition or laboratory tests, especially if anti-rejection drug doses are not sufficient. To detect this type of 'silent' rejection, biopsies are performed several times, at pre-determined intervals.
- The PlexAPRTM blood test measures the risk of rejection. This knowledge can be combined with clinical information to develop a treatment plan.
- Benefits: Rapid non-invasive measurement of the risk of rejection within a few hours can allow the clinician to react expeditiously, and develop a management plan, while confirmatory biopsies are being arranged.
Intended Use
To RAPIDLY assess the risk rejection of transplanted abdominal organs.
Procedure
- PlexAPRTM is a functional cell-based blood test, which rapidly measures presentation of donor antigen by recipient B-cells in cell culture.
- The test requires whole blood in sodium heparin tubes to be shipped at ambient temperature for overnight delivery to Plexision's laboratory. A five mL (3 mL minimum) whole blood sample is needed.
- Recipient B-cells, which present donor antigen and recipient B-cells which present reference antigen are measured with flow cytometry.
- Results are expressed as an antigen presenting index or API, which is a measure of the risk of rejection.
- Results are reported on the same day that the blood sample is received at the laboratory.
- The PlexAPRTM test has been evaluated in over 130 children and young adults with abdominal transplants.
Performance
The PlexAPRTM test is performed in Plexision's CLIA- approved, CAP-accredited laboratory and
- Has been evaluated during routine clinical monitoring, in relation to for-cause biopsies and in relation to surveillance biopsies, which are performed at pre-determined intervals.
- Identifies liver or intestine transplant recipients experiencing rejection with sensitivity and specificity approaching or exceeding 80%, respectively, in post-transplant samples.
Benefits
Rapid non-invasive measurement of the risk of rejection within a few hours must be combined with all available clinical and laboratory data to make clinical decisions. This information can allow clinicians to react expeditiously to develop a management plan for abdominal transplant recipients with organ dysfunction, while confirmatory biopsies are being arranged.
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 PlexAPRTM, if there is no insurance coverage. For additional information, call 1.855.753.9474 or email info@plexision.com
Samples & Handling
| # | CATEGORY | DETAILS |
|---|---|---|
|
1 |
Sample Type |
Whole blood collected in a sodium heparin (green-top) tube. |
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2 |
Volume |
3-5 mL. |
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3 |
Transport Conditions |
Ship priority overnight, at room temperature. Sample must get to Plexision within 30 hours of phlebotomy. |
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4 |
Specimen Stability |
30 hours at room temperature from the time of phlebotomy. |
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5 |
Sample Discard Criteria |
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How to Order
| # | CATEGORY | DETAILS |
|---|---|---|
|
1 |
Test Brochure | View and download the product brochure here. |
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2 |
Ordering Tests | Please complete this form, print, and fax to 412-224-2776. |
PlexAPRTM is a lab-developed blood test that helps your healthcare provider determine the risk of rejection af transplanted abdominal organs.
Abdominal organ transplant recipients can benefit from the PlexAPRTM test.
The PlexAPRTM must be ordered by your healthcare provider. The test requires a teaspoon of blood sample. This sample is to be shipped overnight to Plexision's laboratory for analysis. Results are reported to your healthcare provider on the same day that your sample arrives at the laboratory. Your healthcare provider will help you understand the results.
Results are ready within 6 hours after the laboratory receives the blood sample.
The PlexAPRTM test determines whether the recipient's immune cells are processing excessive amounts of donor antigen derived from the transplanted organ. This response occurs during transplant rejection and can be measured by a type of white blood cell called the B-cell. When present, this increased immune response tells your healthcare provider whether transplant rejection is likely.
The results are reported as an Antigen Presenting Index or API. An API less than 1.1 implies a decreased risk of rejection. An API of 1.1 or greater implies an increased risk of rejection.
When combined with available clinical information and laboratory test results, RAPID detection of the risk of rejection can help the clinician determine whether additional tests are needed to confirm rejection, whether anti-rejection medications need adjusted, or whether other testing is needed.
The PlexAPRTM 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. If there is no insurance coverage, Plexision patient assistance plans will assist with the cost of PlexAPRTM.
1. Patent 10222374
2. Biorxiv https://www.biorxiv.org/content/10.1101/2022.10.17.511155v1
3. Am J Transplant. Feb;16(2):497-508. 2016. PMID: 26663361
4. Gastroenterology. Sep;135(3):830-9, 2008. PMID: 18639552
5. CLIA ID: 39D2042664