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'''AlloMap Molecular Expression Testing''', developed and commercialized by XDx, is a gene expression profiling test
▲AlloMap test results are reported as a single score, a number from 0-40, with lower scores indicating a lower probability of moderate/severe [[acute rejection|acute cellular rejection]] (ACR) at the time the test was performed. The performance characteristics of the AlloMap test make it best suited to help indicate that an acute cellar rejection is not present. The AlloMap score is based on the amount of [[RNA]] from each gene in a 20-gene panel comprising of 11 rejection-related genes and 9 genes used for normalization and quality control. Many of the rejection-related genes are associated with biological pathways involved in the [[immune]] response and rejection processes.<ref>Dedrick R. Understanding [[Gene Expression]] Patterns in Immune-Mediated Disorders. J Immunotox 2007 Jul;4(3):201-7. [http://www.ncbi.nlm.nih.gov/pubmed/18958729 PMID:18958729]</ref>
AlloMap has been commercially available since 2005 as a CLIA approved Laboratory Developed Test (LDT) and was cleared by the [[FDA]] in 2008 as a Class II Medical Device.<ref>http://www.accessdata.fda.gov/cdrh_docs/reviews/K073482.pdf</ref> It is available only from the XDx Reference Laboratory in Brisbane, CA.▼
▲A clinician uses the AlloMap test score, along with other standard clinical assessments, to evaluate the patient’s probability of acute cellular rejection and the need for additional [[diagnostic]] evaluations. AlloMap is not designed to be informative about other forms of heart rejections such as antibody-mediated rejection (AMR) or [[cardiac]] [[allograft]] vasculopathy (CAV).
The use of the
▲AlloMap has been commercially available since 2005 as a CLIA approved Laboratory Developed Test (LDT) and was cleared by the [[FDA]] in 2008 as a Class II Medical Device.<ref>http://www.accessdata.fda.gov/cdrh_docs/reviews/K073482.pdf</ref>
▲The use of the AlloMap test is described in the recommendations for the non-invasive monitoring of acute heart transplant rejection in the first evidence-based clinical practice guidelines for the care of heart transplant recipients issued by the International Society of Heart and Lung Transplantation.<ref>Costanzo MR et al. The International Society of Heart and Lung Transplantation Guidelines for the care of heart transplant recipients. J Heart Lung Transplant. 2010 Aug;29(8):914-56. [http://www.ncbi.nlm.nih.gov/pubmed/20643330 PMID: 20643330] http://www.ishlt.org/publications/guidelines.asp</ref>
== Development ==
The
Initial clinical experience at three medical centers was
==
=== CARGO Study ===
The development and clinical validation of the
▲Initial clinical experience at three medical centers was later published in 2006 and the data confirmed the efficacy and performance of the AlloMap test.<ref name="Starling">Starling RC, Pham M, Valantine H, et al. Molecular testing in the management of cardiac transplant recipients: initial clinical experience. J Heart Lung Transplant. 2006 Dec;25(12):1389-95. [http://www.ncbi.nlm.nih.gov/pubmed/17178330 PMID: 17178330]</ref>
=== IMAGE Study ===
A comparative effectiveness study, the Invasive Monitoring Attenuation through Gene Expression (IMAGE) Study,
== Indications for Use ==
The test is currently indicated for use in heart transplant recipients 15 years of age or older, and at least 2 months (≥55 days) post-transplant.
AlloMap is based on standard quantitative [[real-time polymerase chain reaction]] technology (qRT-PCR) using RNA isolated from peripheral blood mononuclear cells (PBMC). A blood sample is collected, PBMC are isolated, lysed and the released RNA stabilized and frozen (PBMC lysate). RNA is then purified from the PBMC lysate. After purification, RNA is converted into complementary DNA (cDNA), and mixed with gene-specific primers and probes. The expression of each gene is then measured by amplification and fluorescence detection using a qRT-PCR instrument. A mathematical classifier combines the measured expression values for each gene into a single value reported as an AlloMap score between 0 and 40.▼
== Method of use ==
Each AlloMap score is associated with a [[Negative Predictive Value|Negative Predictive Value (NPV)]] and a [[Positive predictive value|Positive Predictive Value (PPV)]]. AlloMap testing is characterized by high negative predictive values and is therefore a test used to help identify patients at low probability of rejection. The AlloMap test has a relatively low positive predictive value, meaning that even when the AlloMap score is relatively high, the risk of rejection may still be low.▼
▲
▲Each
== References==
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